Air pollution is among the many factors that cause atmospheric destructions across the world. Air pollution leads to gaseous imbalances in the atmosphere, which cause chemical reactions amongst different gas molecules.
These chemical reactions produce intense heat in the atmosphere, hence rendering into abnormal increases in the temperatures across the world. Air pollution is rated to be the major cause of discomfort in the living creatures of the world for air is essential for the survival of every living creature. Therefore, distress in the environment due to air pollution causes discomfort in all living creatures and worst still cause deaths.
Causes of air pollution
There are various causes of air pollution, which include industrial fumes, agricultural input products, domestic, and urban effluents. Beginning with the industrial fumes, the majority of manufacturing factories emit gaseous fumes into the environment as a byproduct of fuel and chemical combustion that produces the energy necessary for the production processes.
Today’s technology does not have the ability to develop necessary measures of emitting gaseous effluents safely into the environment (Parry, 2007). Instead, there have been proposals concerning various methods of energy saving that is environmentally friendlier but cannot be used for large factories.
Some of the environmental friendlier ways of saving energy include the use of solar and wind-power energies that do not have harmful wastes as compared to other forms of energy production such as the use of diesel generators in factories.
Based on the research results of the United Nations Environmental Program, wastes from industries are the major causes of air pollution. Industries are responsible for emitting the most harmful gases such as sulfuric gases that are highly responsible for the depletion of the earth’s ozone layer.
The research recommended for safer methods of emitting gaseous effluents, which included the introduction of intoxication chambers that contain water for dissolving the gaseous wastes. Sulfuric compounds dissolve in water, thus making the gaseous effluents less harmful to the ozone layer (U.S. Environmental Protection Agency, 2012).
In addition, the research also recommended the shutting down of factories that emitted sulfuric compounds into the atmosphere as a method of trying to save the ozone layer from extreme depletion (Gillespie, 2005). The researchers found that the depletion of the ozone layer also results from human activities.
However, developed nations have contributed highly to the depletion of the ozone layer due to having many industrial activities that emit large amounts of harmful gases into the environment. Hence, the developed nations, which included the United States, the United Kingdom, Germany, France, and others leading industrialized nations were said to be the leading in the emitting of harmful gases and chemicals into the atmosphere.
Implementation of the research recommendations seemed a great challenge to the developed nations as it required the creation of novel technologies that would cut down the emission while introducing new methods of emitting such wastes.
Consequently, in the United Nations Climate Change Summit, the developed nations were reluctant of signing the agreement for the implementation of the above recommendations, which showed their resistance in participating in the efforts toward saving our world from climatic changes due to the depletion of the ozone layer.
Secondly, agricultural inputs are considered as causes of environmental pollution especially water, air, and soil pollution. The majority of farmers in today’s world use newly introduced methods of agriculture, which include the use of industrial chemicals inform of pesticides, insecticides, and fertilizers.
Those chemicals emit harmful gases into the environment that contain sulfuric compounds that are responsible for the depletion of the ozone layer. The environmental management organizations, the majority of which are non-governmental organizations have embarked on campaigns that are aimed at sensitizing farmers to adopt organic methods of farming since they are less harmful to the environment.
Various methods through which agricultural inputs deplete the earth’s atmosphere include both biological forms and chemical forms. For the biological forms of environmental depletion, plants are responsible for emitting gaseous wastes that are harmful to the environment.
Plants are normally required to emit either oxygen or carbon dioxide gases into the atmosphere, while harmful agricultural chemicals that are rich in heavy metal compounds such as sulfur compounds destabilize this process leading to the plants emitting sulfuric compounds into the atmosphere. Hence, farm chemicals that contain heavy metallic compounds are harmful, and they cause air pollution.
Domestic and urban effluents are considered to be among the major contributors of the depletion of the ozone layer. The majority of human activities contribute to the depletion of the environment and especially the earth’s atmosphere (McMichael et al., 2003). The research studies conducted by the United Nations Environmental Program showed domestic and urban effluents as the third major contributors to air pollution.
Large quantities of domestic effluents produce harmful gases after being disposed into the environment. For instance, the majority of food packages contain chemicals that are used as food preservatives and when they are disposed of, they react with oxygen and thus produce harmful gases such as ammonia and sulfuric acid gases, both of which are harmful by degrading the environment.
Other human activities that cause air pollution include the use of motor vehicles and other automobiles, which emit harmful gases due to gaseous combustions both at the domestic and urban environments.
Effects of Air Pollution on Weather Patterns and Climatic Changes
There are various harmful effects of air pollution on the lives on earth. Air pollution causes the death of both plants and animals due to discomfort and stress in the air circulation mechanisms (Tol, 2009). The effects of air pollution include weather and climatic changes that have been a major concern to the environmentalists.
Air pollutants that contain sulfuric compounds cause too much depletion of the ozone layer. The ozone layer is responsible for regulating temperatures on the earth’s surface by reducing the heat that the sunrays emit to the earth’s atmosphere.
The depletion of the ozone layer by air pollutants causes the unwanted heat emissions of the sunrays to find their way to the surface of the earth, and hence causing an unwanted rise in the temperatures on the earth’s surface. Scientists refer to that effect of air pollution as the greenhouse effect, which is a comparison to the horticultural greenhouses.
The greenhouse effect is dangerous for animal and plants survival on earth as it leads to abnormal increases in temperatures and hence changing the climatic condition of a place because of increased temperatures (McMichael et al., 2003).
For instance, Polar Regions that are well known to be cold for centuries have been experiencing a rise in temperature that often lead to the melting of icebergs. Such conditions have led to the change in the climatic conditions of the earth’s Polar Regions.
Scientists argue that temperature is the key determinant of the climatic condition of a place for temperature variations determine the movement of winds as temperature rise creates conventional currents of air movement (Johnson, 2012). A rise in the atmospheric temperature raises the temperature of the air particles near to the ground surface, and as a result, they become less dense and rise above the cold particles in the atmosphere.
On the other hand, the cold air temperatures in the atmosphere, being denser than warm air particles, falls to the ground surface to occupy the vacuum left by the warm air particles. The process continues, and hence creating convention currents of air, which in other terms is referred to like the wind. On the other hand, the wind is responsible for the movement of clouds and the direction of their movement.
In most cases, areas that experience high temperatures and are near to large water bodies capable of forming clouds experience high rainfalls due to the presence of winds, and in most cases, such areas experience conventional rainfalls. The prolonged process of temperature various, wind, and rainfall, which in a short-term can be referred to as a change in a weather pattern, leads to the change in the climatic condition of a place.
Conclusion
Natural gases, which form a crucial part of elements that support both human and plant life, are suspended in the Earth’s atmosphere. Therefore, any pollutant getting into the Earth’s atmosphere cause air pollution, which distorts the natural balance of the air components thus leading to chemical reactions in the air. These chemical reactions lead to an increase in the temperatures on the earth’s atmosphere.
Ultimately, the chemical reactions initiate changes in weather patterns across the world in a phenomenon that can explain the current global warming trends. Prolonged changes in the weather patterns lead to the change in climatic conditions of a place.
There are various causes of air pollution, which include industrial fumes, agricultural input products, domestic, and urban effluents. Finally, air pollution causes the death of both plants and animals due to discomfort and stress in the air circulation mechanisms.
Reference List
Gillespie, A. (2005). Climate change, ozone depletion and air pollution: legal commentaries within the context of science and policy. Leiden, Dutch: Brill Publishers.
Johnson, S. (2012). UNEP the first 40 years. New York, NY: United Nations Environmental Programme.
McMichael, A., Campbell-Lendrum, D., Corvalan, C., & Ebi, K. (2003), Climate Change and Human Health. Risks and Responses. Washington D.C: World Health Organization.
Parry, M. (2007). Climate change 2007: Impacts, adaptation and vulnerability: working group II contribution to the fourth assessment report of the IPCC Intergovernmental Panel on Climate Change. London, UK: Cambridge University Press.
Tol, R. (2009). The Economics Effects of Climate Change. Journal of Economic Perspectives, 23(2), 29-51.
U.S. Environmental Protection Agency. (2012). Six Common Air Pollutants. Web.
Air pollution, as the name suggests, is the condition by which the atmosphere becomes contaminated by other foreign substances thus becoming unsuitable for living things and the environment. High concentration of different pollutants in the air causes a number of adverse effects to both living things and the environment.
Some of these effects in the case of living things include discomforts, illnesses, and death. Air pollution also instills serious damages on both built environment and the natural environment, among other aspects of life.
This research paper examines at least twelve topics under the subject of air pollution in an attempt to bring valuable insight on the complex issue and its vast impacts on humans and the environment.
The Importance of Air
This topic is of great interest as far as this subject is concerned, simply because it revolves around one of the most important things which humans need to know about the air they breathe and the role it plays in their lives.
This topic is significant in that, it highlights some of the ways through which humans and other living things benefit from air as a key necessity of life.
Living things, comprising of human beings, plants and animals cannot survive without air used for breathing and photosynthesis purposes, among other processes of life (Gurjar, Molina & Ojha, 2010).
The earth’s atmosphere comprises of a mixture of various gases such as oxygen, argon, nitrogen, and carbon dioxide among others. Even though oxygen is arguably said to be the most important gas when it comes to supporting life, all these gases do play a significant role in a number of ways.
These ways include, but are not limited to, reduction of extreme temperatures, warming of the earth’s surface, and absorption of ultraviolet solar radiation.
The excessive release and accumulation of pollutants in the atmosphere over the time has contaminated the air, thus triggering complex issues on human health and the environment.
Air Pollutants
This particular topic is of interest since it raises serious concerns on the issue of air pollutants and the role they play in raising unfavorable conditions on living things and the environment.
This topic is also important in a number of ways, one of them being that it helps people understand the many aspects in life that could pass out as air pollutants.
Air pollutant is a phrase applied to refer to various substances in the atmosphere that are likely to generate harmful conditions to people and the surrounding environments. As it would be observed, air pollutants can be in the form of liquids, solids and gases.
For easy understanding, pollutants of air are grouped into primary and secondary pollutants. The first class comprises of those pollutants which result from a direct emission of a particular process.
A good example here is the burning of fossil fuels in motor vehicles, where carbon dioxide is emitted into the atmosphere as the main pollutant. Secondary pollutants on the other hand, are not produced directly, but would tend to form in the atmosphere whenever there is a reaction or interaction of primary pollutants.
As it would be observed, there are various primary pollutants that are directly associated with human activities. Examples of these include, but are not limited to, volatile organic compounds, nitrogen oxides, carbon dioxide, ammonia, persistent free radicals, particulates, sulphur dioxide, and odors.
Examples of secondary pollutants are peroxyacetyl nitrate and ground level ozone, among other harmful gaseous products. All these pollutants do play a significant role in the air pollution process.
Historical Explanation on Air pollution
This topic is of great interest in this subject in that, it gives a deeper insight on the impacts of air pollution on human health and environment based on historical observations.
The topic is also very important because it helps us understand some of the factors that have necessitated the complex issue of air pollution which has become a serious global issue in the current world.
Industrialization and globalization are two aspects of modern development that have played a key role in the advancement of high levels of air pollution witnessed in the world today (Heck, Farrauto & Gulati, 2012).
Before the wake of modern industrialization and globalization, the systems of nature would successfully maintain the cleanness of the atmosphere.
The various cycles of life taking place in the atmosphere and on the earth’s surface, ranging from evaporation and precipitation cycles, to the transpiration and photosynthesis processes took place freely.
This however, would change abruptly with heightening industrialization and urbanization, where more hazardous wastes or substances emitted from various processes of human activities started going into the atmosphere in levels that could not be controlled by the systems of nature.
Those activities, however, have led into adverse effects of air pollution.
Sources of Air Pollution
This topic is of great significance and interest as far as the issue of air pollution is concerned. There is no way we can address this particular issue affecting the global community without examining the various contributing factors that are directly linked to it.
Therefore, the importance of this topic is that it provides a further understanding on the main sources of air pollution in the current world. There are various sources associated with the issue of air pollution which has transcended into a matter of debate allover the world.
These sources of air pollution are divided into four major groups which include natural sources, stationary sources, area sources, and mobile sources. Natural sources constitutes of aspects such as volcanoes, dust, and fires.
Stationary sources are things such as factories, power plants, and oil refineries, among other industrial facilities and projects. Area sources would include smaller sources of pollution which can only be effective when combined with other players.
The last category of sources; mobile sources, would consist of all types of automobiles. As a matter of fact, these are arguably the most dominant players responsible for the excessive air pollution observed in the world today, accounting for more than half of the overall air pollution.
Health Impacts of Air Pollution
This topic is of interest to me because it touches a major area of concern on this subject. The topic is also significant in that, it examines air pollution as an important risk factor for many health conditions and behaviors affecting humans today.
Some of the adverse health effects directly associated with air pollution include issues such as heart diseases, respiratory infections, and cancer of the lungs, among other serious health complications (Haines, Kovats & Campbell-Lendrum, 2006).
These health conditions are normally characterized by excessive coughing, aggravation of cardiac and respiratory conditions, and difficult in breathing among other complications. As it would be observed, the effects of bad or poor quality air on human health are far reaching and therefore cannot be overestimated.
These health issues can always result to increased medical costs, increased medication and medical attention, and premature death.
According to a current report courtesy of the World Health Organization (WHO), the adverse effects of bad air have claimed more than 3 million human lives worldwide.
This raises concern on the increasing levels of air pollution in the world as something which calls for serious attention from global policy makers, especially those who are aligned to this field.
Environmental Impacts of Air Pollution
Just like the one addressed in the above paragraph, this topic is also of great interest to the subject matter of this research paper. This is simply because it revolves around another major area of concern as far as the complex issue of air pollution is concerned.
The most important thing with this topic is that it provides an in-depth insight on the impacts of excessive air pollution on both built and natural environments. There are various ways through which air pollution damages the environment.
For instance, crops and trees can be permanently destroyed through the effects of ground-level ozone. Excessive pollution of air also leads to ozone depletion, following the emission of harmful gases and man-made chemicals into the atmosphere.
This has led to high levels of ultraviolent radiation in the air, whose harmful effects have been realized allover the world, especially through the issue of skin cancer, which is directly linked to excessive exposure to harmful radiations.
There is also the effect of acid rain, where harmful amounts of acidic substances are released into the atmosphere and end up bringing serious effects on soil and water later on, when they come back to earth in the form of rain.
This in turn makes the environment and water bodies unsuitable for wildlife and the aquatic life, respectively. Excessive air pollution can also trigger eutrophication of water systems, thus leading to deaths of animals, fish and plants.
Aerosols and Visibility
This topic is also of significant interest to this research work based on the stand it takes in explaining the facts surrounding the subject matter. This topic introduces a very important aspect of air pollution known as aerosol, with a further focus on how these specific substances are formed in the air.
However, of great importance here is the fact that, the topic does not only introduce the concept of aerosols, but it also explains how this pollutant tends to affect human visibility in regions where they it is commonly observed. Air pollution aerosols constitutes of smoke and smog.
These substances are normally characterized with a lifetime of not less than two minutes, a duration which is enough to raise serious visibility problems on humans. Aerosols can result from either primary aerosols or from a reaction of chemicals and gases.
Among other serious health effects, aerosols are known to cause serious impacts on human visibility in places where they frequently occur.
For these reasons, the emission of aerosols in the air has become a major issue of concern allover the world and it is one of the many issues that need to be addressed and controlled as far as air pollution is concerned.
Effects of Air Pollution on Children
Like the other topics that have been addressed so far, this particular topic also revolves around the complex issue of air pollution in the world, and this makes it a subject of interest in this research paper. The topic is also important in that, it observes the impacts of this overwhelming issue on children.
Young children are said to be highly exposed to the vast effects associated with air pollution. Apart from the many health problems observed earlier that do affect humans in general, there are others which are specifically known to affect children, as a result of exposure to excessive air pollution.
Some of these health complications include pneumonia and asthma, among other serious respiratory infections. The fact that children spend much of their time outdoors makes them prone to many risks of bad air or atmosphere resulting from the effects of hazardous gases and particulates in the atmosphere.
In just another perspective, issues of low initial birth weight are observed to be common in regions where humans are highly exposed to contaminated air.
As it would be observed, many developed and developing countries have introduced strong protective measures to help protect their future generations from the heightening effects of air pollution.
The Relationship between Air pollution and global warming
This topic is of great interest in that, it tackles one of the most serious issues of the modern times arising from excessive pollution of the atmosphere.
However, the importance of this topic in this subject is that, it introduces the highly debated issue of global warming as the most serious implication of air pollution affecting the global populations.
This topic also addresses with a considerable emphasis some of the serious effects linked to this international crisis on humans. Climate change is said to have become an issue of concern allover the world, considering the damaging issues it presents on environment and living things.
Greenhouse gases, especially carbon dioxide, are major contributing factors towards the issue of global warming.
As it would be observed, the world has witnessed excessive emission of these gases over the years as a result of excessive use of automobiles, among other human activities that rely on fossil fuel as the main source of energy.
The continuous application of such activities for the last one and half centuries has produced enough greenhouse gases in the air, thus raising their levels in the atmosphere to a point which cannot be controlled by nature.
Mitigating the Effects of Air Pollution on Human Health and Environment
This topic is of great interest and importance to this subject since it explores some of the approaches that can be applied in slowing down the adverse effects of air pollution on human health and the environment.
The global air pollution is a serious issue that needs to be addressed with immediate effect and concern by all countries in the world.
This can be achieved by ensuring that effective control and mitigation measures are applied where necessary, to help lessen the intensity by which this issue is affecting living things and the environment.
One effective way which has been used in an attempt to achieve this important goal is by limiting the use of fossil fuels by industries and automobiles.
This has been achieved through the use of alternative sources of power or energy such as solar batteries and electricity in powering these machines that have previously been powered through burning of fossil fuels, which is considered to be one of the heaviest pollutants of the atmosphere today.
Another effective way of mitigating the effects of air pollution on both humans and the environment is through the use of cleaner fuels such as biodiesel and bioethanol.
Ways of controlling air pollution
This is another topic which is of great importance here for it examines the various ways that have been used by the international communities in an attempt to control air pollution and its adverse effects on human health and the environment.
I have found great interest in this topic, because it raises much concern on various potential as well as existing control measures, thus giving important information on how they are used to control air pollution.
Effective use of land and protection of environment through modern technological approaches are some of the approaches used in controlling air pollution.
Other significant approaches here would include things that can be achieved on a personal level, such as conservation of resources, recycling, and less driving or flying to minimize the extent by which fossil fuels are burned to release harmful gases into the air.
A number of physical processes aimed at removing airborne particulates and substances from airstreams are also performed in some regions using modern equipments.
This would include the use of things such as scrubbers, baghouse filters, cyclones, and electrostatic precipitators, among other modern equipment that have been designed for these specific roles.
The ultimate use of internal-combustion engines in some countries has also proved to be a satisfactory long-term solution to the complex issue of air pollution.
Legal Regulations on Air Pollution
The main significance of this topic is that, it revolves around the many legal regulations that have been introduced worldwide in an attempt to combat air pollution and its adverse effects on human health and the environment.
This topic is also important in that, it gives a concise explanation of how these regulations are enforced through the required channels in ensuring that air pollution is fully controlled and mitigated across the world.
Primary regulation, which comprises the use of permissive rules and regulations, is another approach which has proved to be useful in controlling the adverse effects of air pollution in the world (Jacobson, 2009).
The many effects that are directly associated with air pollution have raised increasing alarm of what could become of the matter if it was ignored by the international community.
This overwhelming concern has resulted into the development of significant legislations on the quality of air, as enforced by the Environmental Protection Agency.
A good example here is the Air Pollution Control Act, 1955, which has undergone various developments through a series of new laws over the years. Through such regulatory acts, the Environmental Protection Agency plays a key role in maintaining air quality in the world.
Conclusion
Air pollution has become a major topic of concern allover the world, owing to the many effects it brings on living things and the entire natural environment.
As it is evident from this paper, this overwhelming issue has plagued the global human communities for many years since the industrial revolution when massive cases of air pollution than nature could cope with were first observed.
As it would be observed, many projects have so far been undertaken with the aim of combating this complex issue. However, there is still room for more intervention to limit the effects of air pollution on human health and the environment.
References
Gurjar, B., Molina, L., & Ojha, C. (2010). Air pollution: health and environmental impacts. Boca Raton, Florida: CRC Press.
Haines, A., Kovats, R., & Campbell-Lendrum, D. (2006). Climate change and human health: impacts, vulnerability, and mitigation. The Lancet, 367(95), 150-159.
Heck, R., Farrauto, R., & Gulati, S. (2012). Catalytic air pollution control: commercial technology. New Jersey: Wiley Publishers.
Jacobson, M. (2009). Review of solutions to global warming, air pollution, and energy security. Energy & Environmental Science, 2(2), 148-173.
Water pollution refers to a situation where impurities find way into water bodies such as rivers, lakes, and ground water. Pollution manifests when impurities enter water bodies through various direct or indirect processes (Beard, 2012). Contamination of water affects survival of plants and other living organisms within its ecological context. Pollution affects ecological balance within water bodies.
Through pollution, organisms and plants have difficulty surviving in their natural environment. Water pollution is a phenomenon that requires attention in order to halt its devastating effects on water ecology. There is need for stringent measures to guarantee and enhance proper management of water resources.
Lack of such laws and measures could lead to destruction of crucial water towers around the world (Beard, 2012). Water pollution is a major cause of preventable deaths in contemporary society. Indeed, water pollution is a phenomenon that requires joint efforts to ensure its management and control.
Discussion
In modern society, there are various challenges that affect quality and nature of life on earth. Most of these challenges are preventable and easy to manage. In fact, most of these challenges emanate from imprudent human activities. Such human activities fail to recognize the importance of conserving water and other related resources. Water pollution is a leading cause of death across the world (Beard, 2012).
Experts estimate that more than 14,000 people die every day because of consuming contaminated water. Water pollution is a ubiquitous challenge that affects both developing and developed countries. Polluted water contains impurities that pose danger to human beings and organisms that depend on it for survival.
Natural occurrences such as volcanic eruptions and earthquakes lead to contamination of water resources. Such occurrences affect overall quality of water resources. They lower safety standards of water, making it unsuitable for human consumption (Beard, 2012).
Various categories of water pollution manifest through activities that undermine quality of water resources. One such category is point source water pollution. This is a form of pollution where impurities enter water bodies through distinct sources such as pipes and trenches. This includes cases where raw sewer discharges into water bodies through pipes (Beard, 2012).
In the United States, the Clean Water Act embodies all necessary requirements in prevention of point source pollution. Another category is non point source pollution, which involves entry of impurities that do not have a single identifiable source. This form of pollution usually manifests as a culmination of minor activities that lead to massive pollution.
Through activities such as leaching, various impurities seep into water thereby making it unfit for human consumption. Runoff water from agricultural land leads to contamination and pollution because it carries impurities that clog water bodies. Runoff water from roads, highways, and public fields fall under this category of pollution (Beard, 2012).
The inherent and recurrent connection between surface and ground water is critical in maintaining balance within the ecosystem. Another category of pollution is groundwater pollution. It is usually difficult to characterize this form of pollution because it occurs through discreet procedures and processes that are not easy to determine.
Groundwater resources are at risk of contamination from unique sources that may not necessarily affect conventional water bodies (Beard, 2012). In most cases, this form of contamination occurs through various impurities found within the soil structure. Such impurities contaminate groundwater and make it unsuitable for human consumption.
Various hydrological processes lead to contamination of groundwater by adding impure components to water bodies.
This form of pollution is very prevalent, albeit in a discreet manner (Blundell, 2008). Regardless of its manifestation, groundwater pollution poses monumental challenges to conservationists and environmentalists. In most cases, it is difficult for experts to determine the nature and scope of pollution with regard to groundwater pollution.
There are several causes of pollution in water bodies. Most cases of pollution result from contaminants such as chemical compounds, pathogenic factors, and other factors that alter composition of water (Blundell, 2008).
Most components of water are crucial but usually become contaminants if they exceed acceptable levels and standards. Such natural components have acceptable standards with regard to their ratio and composition in water. If they exceed such levels, they turn into contaminants (Lies, 2011). As a result, they pose danger to human and animal life.
Contamination of water leads to development of diseases that affects human beings. Most common water pollutants include organic and inorganic compounds that enter water bodies. Organic pollutants include detergents and wastes from food processing plants. Inorganic pollutants include various chemical compounds and fertilizers from agricultural fields (Lies, 2011).
Conclusion
Water pollution is a recurrent challenge for environmentalists and conservation experts. It presents challenges for humanity because of its dire effects on human health and wellness. In absence of strategic measures, water pollution threatens to bring more harm to the environment. Increase in water pollution could drastically reduce availability of clean water for human consumption.
This reality necessitates various control measures that seek to reverse current trends of water pollution in modern world. Various conservation organizations and agencies continue efforts to find a lasting and viable solution to water pollution. Indeed, water pollution is a phenomenon that requires joint efforts to ensure its management and control.
References
Beard, W. (2012). Environmental Conservation: Contemporary Approaches. Newyork: Cengage Learning.
Blundell, J. (2008). Implications of Environmental Degradation. London: Algora Publishing.
Lies, A. (2011). Effects of Water Pollution. Newyork: ABDO.
On October 4 2010 a reservoir in Hungary containing toxic sludge from aluminum ore processing, was breached spilling the harmful contents onto the villages and over the adjacent countryside. The chemical components of the sludge are the main issue of concern due to the potential health and environmental hazards that could arise if not checked properly and thoroughly. With particular health concerns, the sludge has been found to contain some heavy metal elements in significant amounts that warrant the possibility of some health risks. Such chemical pollutions result in long-term health complications that are evident much later and which can affect several generations (Turncock 2007). The particular heavy metals are arsenic, chrome and mercury which are associated with life-threatening conditions like Cancer and heavy metal poisoning (Independent 2010).
Cause and Severity of the spill
The spill was apparently a result of the containing dam wall being weak and the ensuing heavy rains rapidly increased the volume of the contents resulting in breaking of the reservoir. Over 150 million gallons of the red mud flooded an area of about 16 square miles resulting in the death of 5 people and the hospitalization of slightly above 100 people, mostly due to chemical burns. Concentration tests indicate that the combined amount of the heavy metals to be around 350 tons most of it being chrome.
The authorities had to deal with reports that the spill would cause more danger to a lot more people if it found its sway onto the Danube River. Homes, property and the residents’ livelihoods have been destroyed and their lives put temporarily on hold. The heavy metals may also find their way into underground water systems from which they can be ingested by people unaware of such a possibility. Fishing on the river has also been affected with a good number of fish dying and the remaining fish being harmful for human consumption since they could have ingested these heavy metals (Szakacs and Than 2010).
To further compound the situation, dry weather has been causing the mud to turn into dust transferrable by air which could result in respiratory problems if these compounds are inhaled. Local rivers have suffered a great deal since their small volumes can not effectively neutralize the alkaline effect of the sludge, and as a result, some of the waterways have been declared dead. Apart from direct implications on people’s health, other risk factors involve agriculture where the topsoil has been rendered practically infertile and will have to be replaced. The immediate risks are minimal but over time they could cause significant concern (Rosenthal 2010).
Intervention measures
After the spill some immediate measures were undertaken to avoid the situation getting out of hand. The people of the nearby village were immediately evacuated to avoid further contact with the toxic mud. The reservoir wall which is suspected to have been weak before the spill, was strengthened through the addition of a stronger outer wall to prevent further future spills. The company responsible for the sludge was temporarily shut down and the boss suspended.
In dealing with the effluent itself, the Hungarian government through the military, instituted a wash-up of the residential areas in order to dilute the alkaline sludge and therefore, reduce its burning effect on the skin. Some gypsum in the form of plaster has also been used to neutralize the sludge since it effectively stops its spread by somehow trapping it. The plaster was used particularly in the rivers and canals. All of this was being done while tests were carried out to determine the constituents of the slurry, specifically whether there was danger in terms of radiation and the levels of the heavy metals.
The contaminated water is being constantly checked by the environmental researchers for levels of toxicity and their toll on aquatic life. Water being consumed is also constantly being examined to ensure that it is not contaminated. Fish products from the contaminated rivers are banned from consumption. The government has also declared that the affected homes will be decontaminated (Rosenthal 2010). Since prevention is the best cure, possible health risks portended by such environmental pollution can therefore be preempted by proper planning and adequate safeguards against these dangers (Turnock 2007).
Recommendations
The Hungarian government must coordinate its environmental and health departments and do all it can to contain the crisis while safeguarding its citizens from the potential health risks. The scale of the disaster must be properly gauged and documented to ensure that all the people who could be affected are established. Health officials should also screen all the people who came into contact with the sludge and those who live within the spill area and its vicinities.
Clean-up efforts should be thorough and subsequent waste should be dumped safely in an area that will ensure that the hazardous refuse does not endanger human life. As previously highlighted, danger in such a case, does not only lie in direct contamination, health complications may also arise from indirect contamination from consumption of contaminated products. With this in mind fish and other animals from the area should be temporarily blacklisted and not consumed; all that is being consumed should come from outside sources and be handled carefully.
Finally, such plants that are a potential hazard to communities must be located in an uninhabited area where possible and if not a respectable distance between the plants and settlements should be imposed.
Air pollution has been an area of concern for many nations around the world. Release of harmful emissions into the atmosphere has greatly affected the lives of many across nations. This issue has attracted the attention of many in an effort to come up with lasting solutions.
According to Archer (2007), air pollution is threatening the existence of nature as the poisonous gases affect the ozone layer and other environmental factors.
This scholar says that if not addressed in a proper manner, air pollution can have serious negative consequences that may be difficult to reverse.
China and the United States of America have adversely been mentioned to be the leading polluters of the atmosphere. China leads other countries in the world in emission of greenhouse gases into the atmosphere. This country has experienced a massive growth of the economy.
It has also seen a massive increase in the number of manufacturing firms within its borders. The cheap skilled labor in the country has attracted attention of many scholars, especially coupled with the large population which also acts as a market for this firm.
However, the main question that has always been asked is whether China’s pollution is unique or not. This question forms the basis of this research.
The researcher seeks to refute the claim that, “although china has high air pollution, there are other countries that should be looked at and that China’s air pollution is not unique”
China’s Air Pollution is Unique
This above statement is controversial as it is irresponsible. According to Alexandria (2007), China is the leading polluter of the environment. The recent statistics indicate that the gap between the level of pollution by China and that the United States is widening.
The level of gas emissions given by China far outweighs that of the entire African continent. There are a series of protocols organized by countries around the world to fight air pollution, and in every meeting, complaints have always been made against China for its sharp rise in air pollution.
Of note has been the Kyoto protocol. The Kyoto protocol proposed that all countries around the world should consider cutting the emission of greenhouse gases into the air. Of note was China which was identified to be increasing its level emission of greenhouse gases.
Saying that the focus should be shifted to other countries other than China is making an irresponsible statement.
There are numerous other countries that have also been faulted alongside china as being large polluters of air (Ochino, 2012). There are those countries that have focused on production of nuclear energy such as Iran.
Scientists have stated that such countries may put the world to a risk should such projects have problems. It is true that these countries may put the world into a risk should such projects break down.
It is true that attention should be given to such countries with the aim of ensuring that the environment is protected from a possible destruction by such unfortunate incidents. However, the focus should not be lost.
The focus should not be diverted from the main source of environmental pollution in the world. An excuse should not be found to make the world believe that China’s case should be set aside for other cases in other countries. Such attempt would be defeating war against this vice of air pollution.
It is true that China’s air pollution is unique. China has had a consistent increase in the number of industries over the past few decades. Within the past five years, China has overtaken the United States and Japan in the emission of poisonous gases into the environment (Houghton, 2004).
This is besides the attempt that environmentalists have made to advise the leading manufacturing countries to cut down on their emission of greenhouse gases.
For a long time, The Green Belt Movement has mentioned the fact that China is emitting greenhouse gases at a rate that may put the world into jeopardy in a near future.
There have been recommendations for this government, and many others to cut down on the levels of greenhouse gases into the environment as a joint effort against air pollution.
However, the response made by this government is not only annoying, but also a clear indication that China is not ready to heed the call for reduced air pollution and a cleaner air around the world.
Conclusion
It is unique that even after realizing some of the negative consequences that their actions may cause, this country has not made a move to ensure that it reduces its greenhouse gases.
It is unique that instead of responding positively to the call of reduction of greenhouse gas emission, this country is still increasing its greenhouse gas emission.
China still remains the leading air polluter in the world. Any fight against air pollution should always start with this country. Giving focus to another country under whichever excuse will be defeating the war against air pollution.
References
Alexandria, K. (2007). The Rise in Global Warming Effects in North America. New York: Cengage.
Archer, D. (2007). Global warming: Understanding the forecast. Malden: Blackwell Pub.
Houghton, J. T. (2004). Global warming: The complete briefing. Cambridge: Cambridge University.
Ochino, G. (2012). Environmental watch. New Delhi: Kwato Publishers.
An ecosystem is often defined as an environment or community, where inter-relationships among organisms take place (Vogt 69). In this respect, plants, animals, natural resources and humans interact for mutual benefits. Other elements such as soil, micro-organisms and non-living things are also included as part of a freshwater lake ecosystem.
A freshwater localized ecosystem
A freshwater localized ecosystem consists of plants and animals of all kinds (Silk & Ciruna 29). Some of these animals and plants exist as producers to other living organisms. For example, the conversion of inorganic matter into organic matter takes place in a freshwater lake. However, plants may perform this process through photosynthesis.
Animals like fish that lives in a freshwater lake, usually feed on plants. The plants have chemical energy obtained from plant as a result of photosynthesis. In this respect, fish and other animals obtain this energy after they consume plants. It is important to note that there are animals or fish that depend on each other for survival. Living things, particularly both animals and plants die and decompose.
Upon decomposing, the matter is changed into organic matter. The inorganic matter can also be obtained from waste produced by animals. Basically, the cycle of both living and non-living organism within a freshwater lake is interrelated and continuous. Without interruptions, this ecosystem is an example of a balanced ecosystem. This ecosystem highly depends on non-disruption from human activities.
Living organisms in a lake and their inter-connection
Biologically, the living organisms in a freshwater lake are referred as biotic elements. The biotic elements depend entirely on each other for survival. For example, fish, amphibians, insects, snails and a variety of water plants live in freshwater lakes (123). The plants provide the fish with food energy.
Some carnivorous fish also depend on other small fish for food energy. The same can be said of amphibians that live off other fish and insects. From this perspective, the living organisms are related through food webs or food chains. An aspect of symbiotic relationship can also be evidenced in living organisms living in a freshwater lake.
An example of such relationship is evidenced when bacteria survive through the legume plants found in the lake. Insects within the lake habitat live off animals and plants without harming them in what is known as commensalism.
Human activities
According to Silk and Ciruna, some of the activities disrupting a freshwater ecosystem are fishing, hunting and pollution (321).
Fishing
Fishing in a freshwater lake targets fish. In this respect, fishing without control measures may lead to fish extinction from the habitat (245). Eventually, there is an ecosystem imbalance within the lake. For example, amphibians no longer have a source of food. Eventually, some living organisms that depend on fish as a source of food also die.
Hunting
Humans hunt amphibians such as crocodiles, alligators and hippopotamus. Humans hunt these animals for food and skin (231). Eventually, some living organisms like fish over-multiply and affect the production of other important organisms such as plants due to over-dependency.
Pollution
Humans are known of polluting freshwater ecosystems by using pollutants like oil, waste materials and other activities. This is done through dumping of toxic substances into the freshwater (240). Such activities affect the environment and living organism may die from toxic exposure.
Works Cited
Silk, Nicole and Kristine Ciruna. A practitioner’s guide to freshwater biodiversity conservation. Washington: Island Press, 2005. Print.
Vogt, A. Kristina. Ecosystems balancing science with management. New York: Springer, 1997. Print.
Many inquiries done into the use of green roofs as pollution control technologies have shown significant relationship between green roofs and pollution control. This inquiry focuses on the use of green roofs to mitigate air pollution when retrofitted to conventional roofs on any building in many parts of the world today.
The paper draws on lessons learnt by retrofitting green roofs to building sin urban areas that have limited space to accommodate conventional gardens. Thus, the study investigates the use of green roofs as measures to mitigate air pollution with special reference to Tehran, Iran.
In addition to that, the current research synthesizes information from literature review son the history of green roofs and types of green roofs. Further inquiries continue into the environmental benefits gained from the use of green roofs in different perspectives and the limitations of green roofs as pollution control technologies.
The paper also examines case studies of green roofs and models the cost benefit analysis of green roofs on the energy and quality of air from a green roof. The model provides a guide on the installation costs and energy saving benefits of a green roof. A further inquiry into the impact of mitigating air pollution on the environment with Tehran as a case study informed the inquiry.
The study culminated in to both external and internal analyses of IKIA, the proposed site for the airport facility. In addition to that, the study has focused on energy consumption activities to understand the chemical processes of carbonCO2 cycles, carbon related emissions, and other pollution emissions affecting the environment.
A regional and site analysis of the proposed site yielded plenty of information on prevailing climatic conditions at the proposed site for airport construction. This study has also established weather conditions, the rate of airflow, and prevalent wind directions in the proposed construction site for an airport facility.
On the other hand, the paper examines air pollution levels, different types of plants that thrive in desert and semi-desert areas, carbon footprints experienced due to air pollution in the proposed area, and the likely benefits gained from the use of green roofs as a pollution control technology.
Aims
The main aim of the study is to conduct an investigation into green roofs as methods to mitigate air pollution with special reference to Tehran, Iran.
To address the question of the effectiveness of green roofs in Tehran, Iran as a method to manage CO2 emissions into the environment
Objectives
The study objectives were:
To investigate the history of green roofs.
To investigate the different types of green roofs.
To examine the benefits gained from the use of green roofs.
To conduct an inquiry into the use of green roofs as methods to mitigate air pollution.
To mathematically model and analyze the benefits of using green roofs for mitigating the effects of air pollution.
To analyze the characteristics of a proposed site for the construction of an airport (IKIA) in Teheran by identifying plants that can be grown in desert and semi-desert conditions for use on green roofs.
To analyze the theories that underlie the use of green roofs and green roofs carbon management systems in order to establish “best practices “for green roofs carbon management systems.
The main aim of the study is to conduct an investigation into the methods used in green roofs to mitigate air pollution with special reference to Tehran, Iran.
Thus, the aim of the research is to inquire into the basic information on the concept of green roofs, to answer the research questions on different attributes of green roofs, methods used to construct green roofs, and the resulting benefits from green roofs.
The study provides detailed information about green roofs particularly for interested parties either in the private or in the public sector on the right choice to make when selecting a green roof with specific design attributes for specific end-user needs. The research is a baseline upon which any interested party can select a green roof.
Typically, any interested party can select a green roof from either of the two options. These options include intensive green roofs and extensive green roofs. On the other hand, the method forms the basis upon which one can identify the benefits of installing a green roof in Tehran and specifically in IKIA city.
In addition to that, the method would also form the baseline to enhance the development pace of a green roof pilot project at the Imam Khomeini Airport City by the Ministry of transportation, the main area of focus. From a historical perspective, green roofs have been in existence since antiquity, with archeological evidence showing their existence to date back to Babylonian times.
At the time, a number of green roofs designed with different objectives in mind with many of them having a lot of aesthetical significance. In addition to that, the purpose of green roofs was to fulfill the views of philosophers, the regard and esteem held for kings and highly regarded people in the Middle East societies.
It was, however, in the modern times that hidden benefits associated with green roofs reinforced the need to study about their construction. These benefits became more apparent with new and emerging challenges associated with climate change mainly due to several activities that lead to air pollution.
That has made governments and individuals in the recent past to realize the importance of incorporating green roofs as pollution control mechanisms on conventional roofs.
Literature review
The history of green roof dates back to many centuries. This research shows that different types of green roofs, constructed in different regions of the world, date back many centuries. These roofs range from ordinary brown roofs to green roofs. Among the regions with documentary evidence on green roofs are the Scandinavian countries and many parts of the European continent.
However, in 1960, the Germans were the first to develop new forms of green roofs. At that time, the purpose of green roofs was to attract tourists and to serve as air pollution mitigating technologies. Research shows that green roofs exist in two categories. These include intensive and extensive green roof. Each of the types of the green roofs has specific and unique attributes making it more applicable to specific environments.
The literature review conducted in this paper details specific and general methods of integrating green roofs to conventional roofs. In addition to that, different construction methods, different material requirements, and maintenance and operation requirements of green roof systems form a significant part of the study.
The methodology of the study is a literature review, which is also a qualitative study of green roof systems. On the other hand, a quantitative study in this paper had its basis on document analysis about the area around Tehran, Iran. The aim is to study the use of green roofs to mitigate air pollution with special reference to Tehran, Iran.
History of green roofs
Modern green roofs are a concept that had its beginning many centuries ago when the construction of green roofs had started in many parts of Europe. According to Basset al, (2003), green roofs were mostly prevalent in the Northern Scandinavian countries with the first modern green roof developed in Germany in 1960.
It was after this, according to Grant et al, 2003, that “the development trends for green roofs spread out to other countries in Europe and USA” p.2. Basset al, (2003) and Grant (2006) suggest a common ground to support the argument that green roofs had been constructed for aesthetical purposes before later developments were designed to address the issue of environmental pollution.
Several authors have investigated the origin and significance of green roofs both in history and in the modern world. The results support the conclusion that green roofs have a history that dates back many centuries. It was to meet the esteem and regard held for kings in the past that many people constructed green roofs. At the time, there was no need to control CO2 emissions into the environment.
Some of the hidden benefits gained from constructing green roofs, according to studies byGrant, Engleback, Nicholson, Gedge, Frith& Harvey (2003) include the capacity of a green roof to control runoff water and mitigate upon the polluting effects of CO2 emissions. Oberndorfer, Lundholm, Bass, Coffman, Doshi, Dunnett, Gaffin, Köhler, Liuk and Rowe (2007) have also established similar facts.
On the other hand,Victoria Transport Policy Institut (2011), Grant et al (2003), and Gedge& Kadas (2004) have additionally suggested that the ever diminishing sizes of land is another reason to develop green roofs in many parts of the world and in particular in Tehran, Iran. Studies by Gedge and Kadas (2004) suggest that the use of green roofs is partly due to increasing population densities in urban areas.
On the other hand, the realities of environmental pollution and the resulting impact on the environment and global climate change are other contributing factors. Not many authors have written about the history of green roofs. However, a couple of authors have provided some examples of the history of green roofs including the green roofs of the Romanian Herculaneum sites and the hanging gardens of Babylon(Basset al, (2003).These studies show that green roofs thrived in different parts of the world centuries back.
In addition to that, these studies also show other areas with archeological evidence that points to prior existence of green roofs to include the Scottish Island with architectural designs that revolve around earth-sheltered huts, pitch covered roofs, and the American mid-west with green roofs made from turf (Grant et al, 2003).
Fig. 1,Grant, 2010
One of the outstanding examples of green roofs, with significant contributions to the modern green roofs was the hanging roof of the Semiramisians. These roofs are among the Seven Wonders of the World. On the other hand, modern green roofs are the most compelling replicas of the Seven Wonders of the World with many features and benefits derived from the complex design and manner of construction.
Additional benefits gained from green roofs include the roofs, which serve as tourist attractions besides serving as methods to mitigate upon the polluting effects of CO2 into the environment (Basset al, (2003). The type of component used to construct a green roof defines the type of vegetation grown on a green roof.
Among the materials used in their construction of a green roof includes waterproofing materials, the medium top surface for the plants, the concrete bricks used to make drainage patterns, and the filtering patterns of the roofs. These and other features, according to Rosenfeld, Akbari, Bretz,Fishman, Kurn,Sailor, Taha (1995) add up to the extra features used to define a green roof. In addition to that, the standards used in their design and development are important issues to consider.
Green roofs
Liu& Minor (2005) and Liu (2004) define a green roof as an architect constructed on a building with a variety of vegetation to fulfill aesthetical appeals of different people. In addition to that, green roofs are-constructed purposely to meet environmental conservation needs, such as air pollution control besides a number of other benefits gained from their use.
Green roofs fall into intensive green roofs, semi-intensive green roofs, and extensive green roofs. These categories rely on the purpose of the green roof, the substrate type, the cost benefits of the green roof, maintenance requirements, and pollution control benefits (Grant et al, 2003).
Research into some of the benefits of green roofs show these roofs to have a great potential as pollution control mechanisms due to their capacity to enhance the energy performance of a building, the ability to improve air quality inside and outside building, and the capacity to provide improved watershed capabilities particularly in urban areas.
In addition to that, another benefit is the ability to absorb carbon dioxide from the atmosphere that is a carbon management and control mechanism (Villarreal, Semadeni-Davies & Bengtsson, 2004).Villarreal et al, (2004). Many authors agree that environmental issues particularly air pollution control is a key benefit gained by constructing green roofs on buildings.
Trumper, Bertzky,Dickson, van der Heijden, Jenkins, and Manning(2009)have shown scientific evidence which suggests that the release of large quantities of CO2into the atmosphere as a result of industrial activities is one of the major sources of air pollution. Scientific evidence shows that the problem is prevalent in many parts of the world today.
Trumper, Bertzky,Dickson, van der Heijden, Jenkins and Manning (2009) have concluded these studies that releasing large quantities of CO2 into the environment is the main cause of climate change and greenhouse gas effects. Estimates show that up to tenfold and even more quantities of CO2 released into the environment every year is due to air pollution activities.
The blame on the principal sources of CO2 has been a matter of exchange between developing and developed counties. Developed countries blame developing countries due to the poor and unrefined technologies used in developing countries. On the other hand, developing countries hold a strong view that developed countries are the principal sources of CO2.
While the rage and debate goes on, greenhouse gas effects are being felt (Trumper, Bertzky, Dickson, van der Heijden, Jenkins&Manning, 2009). Thus, the need for a pollution control mechanism in both situations compels the option to use green roof systems.
Research into the principal sources of CO2, which is the principal cause of greenhouse gas effects, indicates significant contributions from developed and developing countries in their different production capacities. Developing countries are facing exponential population growth, rapid industrialization like China, Brazil, Iran, and many others.
In addition to that, developing countries use unrefined technologies in their quest to industrialize and to compete in the global scene. That has further reinforced need for green roofs as air-pollution mitigation technologies. To keep CO2 emissions and the resulting effects minimal, different strategies and measures include the use of green roof systems are in place.
Other measures in place include governments formulating greenhouse gas policies, use of environmental management methods, and other methods that include constructing green roofs on buildings. Additional methods include the use of carbon capture methods and clean technologies, methods that contribute significantly to carbon management strategies.
Each of these technologies has proven successful to significant levels reinforcing their use as pollution control mechanisms. However, one of the technologies proven successful, both in theory and practice, is the construction of green roofs on conventional roofs. These are facts established with significant support from different authors including (Trumper et al, 2009; Grant et al, 2003; Wong, Chen, Ong& Sia, 2003).
Different Types of Green roofs
As briefly mentioned above, green roofs fall into extensive and intensive green categories. According to Ong and Sia (2003), many authors view green roofs from different perspectives depending on the aim of constructing a green roof and its area of application. The following study is a review of literature on different types of green roofs and the benefits associated with each type of green roof.
Extensive Green roofs
Ong and Sia (2003) view extensive green roofs as a technology that provides a range of benefits to end user and the environment in general. Thus, both public and private users experience these benefits. Public benefits have potential implications as air pollution mitigating methods while private benefits are for aesthetical appeals.
Other benefits associated with the environment include improved air quality, wide-ranging biodiversity, and enhancement of landscape views. On the other hand, Grant et al, (2003) associates these benefits to the environment with particular focus on carbon mitigation capabilities. Thus, it is important to examine some of the characteristics of green roofs.
Wark, Christopher, Wark&Wendy (2003) determined that high porosity substrates are some of the characteristics of extensive green roofs. Further calculations show that the substrate types extend to a depth of between 2 cm and 20 cm (Grant et al, 2003). The Rainwater absorption capacity of an extensive green roof is 75% of the incident rainwater.
In addition to that, extensive green roofs have a water retention capacity of approximately 25% of the rainwater incident on them when studied over a period of 2 months. On the other hand, intensive green roof systems have shown a water absorption capacity of 60% of the rainwater falling on it.
On the other hand, Wark, Christopher, Wark, and Wendy (2003) later established that extensive green roofs constructed on roof required an installation angle of 33% to the horizontal plane. One important attribute of an extensive green roof is its retrofit characteristics. The retrofit characteristics of an extensive green roof are that the roof does not require additional structural support.
On the other hand, Grant et al, (2003) and Wark, Christopher, Wark and Wendy’s (2003) findings indicate extensive green roofs to be light in weight compared with other types green roof. However, Wark, Christopher, Wark and Wendy (2003) and Villarreal, Semadeni-Davies and Bengtsson’s(2004) findings indicate that extensive green roofs demand little or no irrigation for the vegetation to thrive on them.
Typically, that is partly due to the water absorption capacity of the green roof and drought resistant vegetation grown on the roofs. The substrate type on extensive green roof systems has high porosity, lightweight, and low organic composition characteristics. Well-designed and constructed extensive green roofs have shown a high storm-water management retention capacity of 50% of the incident rainwater.
A detailed study by Villarrealand Bengtsson (2005) indicates that a50 mm deep gravel bed, receiving rainwater at a rate of 50 liters per square meter of the green roof surface enables an extensive green roof to acquire a water retention capacity of 50% of the incident rainwater. That is also in consideration of the fact that 100 mm of rainfall fell in that locality in the period under consideration (Grant et al, 2003).
Based on general knowledge, the 100 mm of water readings are from a rain gauge. A rain gauge is a scale commonly used by meteorologists to determine the numerical value of the amount of rainwater falling in a given area. The rain gauge is calibrated in mm from which readings are taken and recorded for a given period. Gradually, the records are analyzed to show the actual estimate of the amount of rain falling in a specific area.
A detailed analysis of rainwater measurements and analysis is beyond the scope of this study. From an economic perspective, extensive green roofs are comparatively cheaper to maintain. Other benefits include the lower cost of construction since extensive green roofs use single layer construction methods.
On the other hand, extensive green roofs require low mowing and weeding activities and can accommodate additional weights. These weights lie between 70 and 170 kg for every square meter of the surface of a green roof (VanWoert, Rowe, Andresen, Rugh, Fernandez, R. T. & Xiao, 2005).
From the “perspective of the community of plants grown on extensive green roofs, it is important to note that drought tolerant plants are the best choice for extensive green roofs” (Grant, et al 2003). A cross sectional design profile of the green roof is illustrated in figure 2 below.
Fig 2, Grant, 2003.
Studies by Toronto and Region Conservation (2006) and The Green Roof Code (2011) have shown that soil requirements for a green roof, the growing medium should be less dense compared with natural soils. Natural soils therefore are much denser.
A comparative analysis of the soil used in the extensive roof systems with natural soils indicates that the planting medium for the weight of an extensive roof lies between 10 and 25 pounds per square meter compared with natural soils, which weigh 100 pounds in a similar size. The weight factor is a benefit for extensive green roofs since they retrofit on conventional roofs without any reinforcements.
A detailed examination of the above extensive green roof shows that the roof is made of a container, a filter layer, a steel dock at the bottom of the structure, an insulation mechanism, a protective layer between a membrane, and a drainage layer.
Several studies by Theodosiou (2003) have shown that extensive green roofs can accommodate drought resistant plants as mentioned elsewhere in this study. Many of the species of plants grown on extensive green roofs belong to the meadow family. These include herbs, turf plants, and the sedum family of plants (Theodosiou, 2003).
Another element of the extensive green roof system is the filtrate layer. According to Takebayashi and Moriyama (2007),the functionality of the filtrate layer is to capture and keep essential components and prevent roots from the growing plants penetrating into the roof that might damage the roof below (Wark & Wark, 2003).
The protective layer prevents chemicals and water from penetrating into the roof below. Deeper penetrations may cause the roof dampen from seeping water. On the other hand, the drainage layer is another component that forms part of the structure of the extensive green roof. Purposely, the drainage layer provides an exit for excess water that has not been absorbed into the entire green roof system.
According to Takebayashi and Moriyama (2007), any design of an extensive green roof system must reflect different characteristics. These include the protective, membrane and protective layers as shown in fig 3 above. According to the design, the green roof stands on steel rollers with different functions.
Steel rollers provide the flexibility to move the green roof system according to user requirements and installation guides. In addition to that, steel rollers integrated into the design of a green roof system provide contact with the conventional roof on which the entire roof system rests. That makes the green roof offer additional functionalities and other benefits(Mentens, Raes& Hermy, 2005).
Another outstanding feature of the green roof system shown in fig 3 is the steel container. The container accommodates all materials used in the construction of the entire green roof system, a fact observed from practical applications of the roof components used in its construction (Mentens, Raes, and Hermy, 2005).
Thus, the overall structure is an assembly of plants, planting media, planting container, filtering layer, drainage layer, protective layer, the membrane, the insulation, and the steel roof deck. The need to use extensive green roofs is due to the benefits accruing from their use on conventional roofs.
Thus, it is important to make informed decision on the choice of a green roof based on the benefits realized from their use as discussed elsewhere. In addition to that, the flexibility of using these green roofs on different types of conventional roofs and the type of plants grown on them are additional considerations to make.
One outstanding attribute of an extensive green roof is that it requires little or no irrigation, making it suitable for semi desert and desert conditions. In addition to that, installing a green roof demands a background area that meets the requirements of an extensive green roof. Technical details and material requirements for extensive green roofs rely on the locality where the roof is to be constructed.
On the other hand, design considerations play a central role in deciding on the type of materials to use in that specific area. Research shows that common design considerations tend to be general irrespective of the area where the green roof system is constructed. Morikawa, Takahasi, and Kawamura (1998) developed a list of design considerations which include:
The structure of the building the green roof is to be constructed.
The load carrying capacity of the building on which the green roof system is to be constructed.
The load capacity of the green roof system
Policy and standard requirements adhered to by the user installing the green roof system.
Water retention and drainage patterns
On the other hand, study reports by Morikawa, Takahasi, and Kawamura (1998) further show that several quality issues need critical considerations before commencing the construction of a green roof on a conventional roof. These quality issues, according to Morikawa, Takahasi, Kawamura (1998), and Liu (2004) include:
The process of installing membranes is the responsibility of qualified and experienced technical staff.
There should be undivided attention particularly when installing each component of the entire green roof system.
Procurement of primary water proofing materials should be from certified sources.
It is important to engage a qualified inspector to identify the appropriateness of the membranes and other materials used in the construction and attachment of the green roof to the conventional roof.
Materials used in the construction should not be opened before reaching the construction site to authenticate their sources and integrity.
Care should be taken to ascertain that job conditions qualify the fact that the health of the workers involved in the work is taken care of.
Water proofing membranes should be 0.036 inches thick. In addition to that, the physical properties of the material used should pass verification tests against standard specifications contained in construction manuals.
Any roofing material should measure to a nominal value of 0.043 inches or as best defined by different specifications fit to specific environments. Other requirements according to the following details in table 1 below.
Table 1 Requirements for a green roof
Component
Description
Drainage board
Made of pre-cast concrete which measure 2*2*2 inches that prevents the growing plants from exceeding the required area.
Vapor retarder
It is the responsibility of the technical personnel to decide to include or not to include the retarder.
Hard scape
Can be made of timber or pre-cast concrete blocks, whichever is convenient.
Liu, 2004
Membrane installation should follow well-defined steps and careful installation procedures to avoid the possibility of puncturing or damaging the membrane. A damaged membrane has the chance of negating the water retention capabilities of the green roof.
Membrane installation should follow instructions outlined in the specifications document of the manufacturer. In addition to that, materials such as rolls used throughout the structure should also follow specification installation standards outlined by the manufacture and other general industry requirements.
In their investigations, Morikawa, Takahasi, Kawamura (1998), and Liu (2004) have established the requirement to flash all penetrating walls in the entire structure of a green roof. That includes drainage pipes and other components of the system. However, Morikawa, Takahasi, Kawamura (1998), and Liu (2004) have established that facts that pitch does not form part of the waterproofing membrane structure.
According toFarzaneh (2005), Liu (2004), and Foxon (2002), water tests occur before declaring a green roof as complete and commissioning it for use. General test requirements are that the area for planting should continuously have a water presence of 24 hours to a minimum depth of 2 inches.
Semi-Intensive Green roofs
Semi-intensive green roofs are a hybrid of intensive and extensive green roofs. Thus, these kinds of green roofs commonly referred to as green roofs are rarely constructed. However, there is little or no literature on these kinds of green roofs (Wark, Christopher& Wark, Wendy, 2003).
Intensive Green roofs
Intensive green roofs are another functional method used to minimize the polluting effects of carbon on the environment. A critical analysis and evaluation of intensive green roofs from a functional point of view shows intensive green roofs to be aesthetically beneficial. In addition to that, space utilization and leisure need are additional benefits gained from green roof systems.
On the other hand, intensive green roofs are characterized by demanding attributes, which include 20 cm substrate depths, frequent irrigation, and restricted access based on imposed legal requirements. On the other hand, maintenance requirements are similar to maintenance requirements for extensive green roofs (Kadas, 2006).
One typical characteristic of intensive green roofs is the communities of plants grown on the roofs are restricted by prevailing weather and climatic conditions. To grow the plants on these roofs, substrate requirements included good exposure, a well-exposed garden, and the use of irrigation facilities, which vary significantly from the requirements of an extensive green roof.
The following diagram represents a typically detailed view of an intensive green roof (Grant et al, 2003).
Fig 3, Grant, et al, 2003
A general overview of green roofs indicates a modular design advantaged by the use of specialized planting trays (Grant, et al, 2003).
Construction Methods
It is important to consider the secondary functions of green roofs before starting the construction processes.Mentens, Raes and Hermy (2005) argue that the main reason driving behind the construction of a green determines the choice of a green roof. Reasons for constructing green roofs are diverse. These, include aesthetical appeals that people view for enjoyment, environmental benefits including an approach to mitigateCO2 emissions into the environment, and other benefits realized from the use of green roofs.
In addition that, it is important to take into consideration the purpose of a green roof by considering important design aspects and specific requirements particularly aimed at addressing environmental issues to mitigate CO2 emissions into the environment. Different authors provide different figures and standards for design and development of a green roof with some of the requirements shown in table 2 below.
One approach is to identify common components that make up a green roof as demonstrated below. That provides a flexible choice when procuring construction materials prior for the construction process (Mentens, Raes& Hermy, 2005). The results are in table 2 below.
Table 2 Reference values for a green roof
Properties
Reference values
Depth
Minimum is 80 mm
Typical one is ≥200 mm
Porosity
Pore size distribution
≤15% by mass
≤ 20 % by mass
d≤0.063 mm
≤ 40% by mass
Maximum water holding capacity (MWHC)
≥25%≤65% (by volume)
≥10% by volume
Air content at MWHC
≤45% by volume
Water permeability
6.0-8.5
6.0-8.0
Organic content
≤65g/l
≤90g/l
Mentens, Raesand Hermy, 2005
On the other hand, other factors to consider are in table4 below for each type of green roof system (Beattie&Berghage, 2004).These factors include the depth of the substrate type, the porosity requirements, the respective size of the porosity, the water holding capacity, air content in the soil, water permeability requirements, and the organic content, and plants content.
Once these facts have been established, construction steps outlined in the table below are followed beginning with step 1 all through to step 4 (Bass&Baskaran, 2003).Research results recommend the need to conduct a cost benefit analysis prior to the installation of a green roof on a building.
Green Roof Cost Analysis
In the repository of general knowledge, it is always necessary to conduct a cost benefits analysis before investing in a project. A cost befit analysis always provides the economic rationale to invest in any particular venture as it minimizes the susceptibility of the potential risk of loss and other unanticipated project problems.
Larson, Matthes and Kelly (2000) view a cost benefit analysis for a green roofs as an essential component particularly when making informed decisions about the kind of roof to construct. That also depends on the locality where project implementation occurs and the potential benefits of investing in the development of the green roof system.
A lot of research on the benefits of green roof systems has dwelt on thermal benefits from green roofs with little research on environmental benefits, thus, making it all more important to conduct an investigation into the monetary benefits of green roofs. The investigation, based on a probabilistically model could provide valuable information to private and public developers on green roofs in terms of the cost savings resulting from several benefits from green roofs (Clark, Adriaens&Talbot, 2007).
Studies conducted byClark, Adriaens&Talbot (2007), Wark, Christopher, Wark, and Wendy (2003), Victoria Transport Policy Institut (2011), and The Green Roof Code (2011) have provided comparative details about the cost of installing a green roof and conventional roofs.
Findings from the studies and other sources of literature have shown that the cost of a conventional brown roof to be $167 with the cost of a green roof shows a standard deviation of $ 28 from the conventional roof. Observations and data analysis of the deviations shows green roofs to be more costly due to variations in design and the additional costs due to the components used to develop a green roof, creating a cost gap between a brown roof and a green roof.
On the other hand, the argument that green roofs are costly compared with brown or conventional roofs rely on established facts based on research findings. Among the benefits gained from the installation of green roofs, include a gap in the installation costs, cost reductions due to storm water management, and the aggregate effects of energy savings from the use of green roof systems on conventional roofs compared with brown roofs.
In addition to that, the thermal efficiency of green roofs is an additional benefit gained from green roof systems. That is particularly due to the efficiency with which green roofs minimize the loss of heat into the surrounding environment. The rate of heat retention by a green roof is mathematically expressed in the following thermal equation:
In the equation, “ΔT is the difference between the ambient temperature and the temperature of the interior of the building under consideration” (Clark, Adriaens&Talbot, 2007). Q represents the flow of heat through the structure under consideration, and A represents the total surface area of the roof in question. The following tabulation shows a clear comparison of the conductance of green roofs between the brown roofs and green roofs (Clark, Adriaens&Talbot, 2007).
On the other hand, cost, social, and private benefits contribute significantly to the number of benefits experienced from the use of green roofs. Further findings based on a comparative analysis of three models are tabulated in table 4 below:
Table 4
Roof conductance according to different green roof models (W/m2/K
Roof type
R-Value model In $
Energy plus model In $
ESP-r model In $
Conventional
0.5
0.38
0.59
Green roof
0.24
0.36
0.42
Mentens, Raes and Hermy(2005).
Another cost benefit analysis conducted based on an evaluation of air quality improvements is based on the mitigating effects of NOX compounds and a sensitivity and financial analysis of the roof systems. The results obtained from the research are in the table45 below (Clark, Adriaens&Talbot, 2007). NPV is the net present value.
Benefit/Scenario
Brown roof ($)
Green roof ($)
% change in NPV
R-Value; mean storm water.
613 969
468 366
23.72
Energy plus, mean storm water.
587 465
468 366
20.27
R-Value, High storm water
619 828
463 944
25.15
Energy plus, high storm water
593 324
443 644
21.81
Low air valuation, R-Value, mean storm water
613 969
443 644
27.74
Low air valuation, Energy and, mean storm water.
587 465
439 222
24.48
Low air valuation, R-value, high storm water
619 828
439 222
29.14
Clark, Adriaens&Talbot, 2007
From the tabulations shown above, the “R-Value” is the mean value of the storm water management of a brown roof and exceeds that of a green roof by 23.72 percent. That shows that a green roof system has more and better storm-water management benefits compared with brown roofs. In the analysis both high and low storm water management methods were basic in evaluating the comparative benefits of brown and green roofs.
In addition to that, comparative values showing in general that green roof systems offer more benefits than brown roofs were also tabulated. Data from the above table provides a brief view of research findings conducted to establish the benefits derived from either type of roofs.
The results indicate gross benefits, which result from either direct or indirect uptakes by plants grown on green roofs, a typical air pollution control mechanism through the green roof systems. However, some limitations such as behavioral characteristics of have limitations on the study.
The baseline of the above study is an analysis of a green roof with a 40-year lifespan to determine or estimate the lifespan of a green roof. From the above data, the NPV varied between a low of 25% and a high of 40% with the green roof experiencing an extra lifespan of 40 years compared with a conventional or brown roof (Clark, Adriaens&Talbot, 2007).
According to Clark, Adriaens, and Talbot (2007), green roofs provide additional insulation benefits compared with conventional roofs. Further research findings indicate additional cost benefits associated with green roofs to include a higher life expectancy compared with traditional roofs. In addition to that, green roofs provide a prolonged lifespan on the water proofing membrane with little or no need to re-roof (Clark, Adriaens&Talbot, 2007).However, the locality where the green roof installation occurs may also influence the price of a green roof.
It is however important to conduct a thorough evaluation of government policies and other related issues to address specific guidelines for constructing green roofs before starting any construction.
Green Roof Maintenance
Studies by Eugene (2008), Carter and Keele (2007), Celik, Morgan, Retzlaff and William (n.d), and Clark, Adriaens andTalbot (2007) show that green roofs require specialized maintenance requirements. However, the operation and maintenance of green roofs depend on the design and the secondary purpose of the green roof. According to Clark, Adriaens, and Talbot (2007), intensive and extensive green roofs have different maintenance requirements depending on their use.
In general, the purpose of a green roof and maintenance requirements ensure that plants and wildlife habitats remain healthy while vegetation grows and gains momentum towards stability. One approach used in the maintenance of green roofs is by sustainably keeping a specified level of moisture content in the soil and ensuring long-term water retention capabilities of the green roof are enforced.
That in effect is to ensure appropriate management of runoff water. To achieve the latter fact, it is important to determine beforehand irrigational requirements of a green roof to ensure a sustained supply of moisture and water needs for the plants and wildlife before the construction and installation of a green roof begins (Eugene, 2008).
However, it is important to formulate a method of minimizing maintenance costs and requirements of green roofs by the use of low–growing plants that limit the need to prune the plants while satisfying the aesthetical needs of the people. It is important to emphasize on the frequency of inspections of the green roof membranes to ensure they do not leak.
If leakages are detected, specialized personnel should take corrective action at an earlier stage to stop the leakages. Personnel should use electrostatic tools to detect fine pinholes to ensure no leakages occur while taking corrective actions where necessary (Eugene, 2008). Eugene (2008) maintains that the frequency of maintaining a green roof system should be monthly or at an interval of three months, or as might be deemed fit by the technical experts based on the type of green roof and its maintenance requirements.
According to study findings by Eugene (2008), Carter and Keele (2007), initial selection of plants on the green roof should provide a basis in decision making on the frequency with which green roof maintenance occurs.
Beattie and Berghage (2004) support the view by different authors that one of the most common maintenance requirements of a green roofs is weeding. Weeding should follow recommendation guidelines contained in the instruction manual developed by the experts.
Other maintenance requirements include plant replacements at the correct time interval. Beattie and Berghage (2004) further affirm regular maintenance requirements should to be done to remove the debris on a routine basis to keep the roof clean.
Green roof Examples
Various examples of green roofs abound. The construction of each type of green roof is based on different concepts based on the objective for which it is constructed. Typical examples of different types of green roofs are shown in the following pictures.
The above picture illustrates an extensive green roof system in Brazil. Details about the roof system and its characteristics as discussed elsewhere in the paper.
Cutlip, 2006
The main objective of the above roof system is provision for a surface for growing plants spontaneously.
Coffman and Davis, 2005
The above example is an extensive green roof, which incorporates a solar heating system specifically for the parking lots. Plants on the roof belong to the Delosperma othona family.
Asner, Scurlock, Hicke,2003
The pictureshown above illustrates an intensive green roof found in Rio de Janeiro. The main objective is to thrill an observer aesthetically.
Bass and Baskaran, 2003
The green roof shown above is in the semiarid north country of Brazil. It is in Campina Grande. The foliage is desert and semi-desert tolerant. They belong to the shrubs and succulents families. Typically, the area covers a substrate are equivalent to 10-20 cm.
Baskaran, 2003
Bass and Baskaran, 2003
The above example of a small and modern green roof incorporated into a city mall. It is meant to fulfill provide aesthetical fulfillments.
Images of green roof examples, n.d.
The above is an illustration of a green roof at a Manhattan island at the Rockefeller Center.
Coffman and Davis, 2005
A typical example of a green roof system in an urban dwelling is in Manhattan on top of the story building as viewed on the picture for aesthetical and air quality management purposes.
Images of green roof examples, n.d.
The above picture represents a typical example of a green roofthat is integrated into the underground area of a garage which includes a number of playground and other physical facilities.
Images of green roof examples, n.d.
The picture shown above is an example of a green roof with sufficient open space for various functions including to satisfy the aestheticsof the viewer
The GRO Green Roof Code, 2011
Green roofs, Benefits and Limitation
The rapid development of green roofs in many parts of the world today is due to the qualitative and quantitative benefits realized from constructing green roofs on conventional roofs. A number of benefits discussed elsewhere bear evidence to the benefits that include mitigating air pollution on the environment (Dixon, Butler& Fewkes, 1999).
From the environmental conservation perspective, green roofs have been studied and known to provide invaluable benefits when used in densely populated areas that are particularly prone to high levels of carbon pollution. Other additional benefits include areas that are devoid of fauna and flora, leading to the conservation of energy and leading to higher energy performance.
Balancing the imbalances that occur on the ecosystem due to the discharge of waste products into the environment is another benefit. The importance of using green roofs on conventional roofs is examined in detail in the following discussion. Based on the benefits gained from the use of green roofs particularly in densely populated areas, the value of a green roof as a pollution mitigating method cannot be underestimated (Eugene, 2008).
Environmental Benefits
One of the benefits gained from the use of green roofs lies on the impact of air pollution on the environmental. One of the environmental benefits includes storm water management besides being a carbon control mechanism among other benefits. In theory and practice, energy conservation is another environmental benefit associated with the construction of green roofs (Takahashi, Konaka, Sakamoto & Morikawa, 2005).
Energy Conservation
Celik, Morgan and Retzlaff (n.d) provides a mathematical model for calculating the energy conservation of green roofs based on the mathematical expression discussed below.
Mathematical Modeling
One approach upon which the mathematical model is developed is based on the conservation of energy due to the use of a green roof on which a variety of plants is grown on the growth medium. In this case, one outstanding method green roofs prevent heat loss is through evapo-transpiration. From the energy conservation point of view, evapo-transpiration is direct shading used to curb evaporative cooling and the effects of direct cooling.
One distinguishing characteristic in the conservation of energy is the ability these plants have to radiate energy previously absorbed back into the environment. On the other hand, another attribute of these plants is their ability to conduct heat through the growth medium on a green roof. It is important to equip one with a mathematical tool or model to analyze the thermal performance of green roofs before a further discussion of additional thermal benefits of green roofs concludes the inquiry (Celik, Morgan& Retzlaff, n.d).
Energy and Environmental Benefits
Having developed a mathematical model upon which the thermal performance of a green roof can be calculated, it is important to develop a detailed view of the benefits that are gained from the use of green roof vegetation in relation environmental performance and benefits of green roofs(Liu, 2002).
According to the Journal of Roof Consultants Institute (2004), thermal benefits result from the heat energy efficiency experienced due to the enveloping effect of a green roof on a building. Comparing brown roofs with green roofs in terms of thermal performance, green roofs have better thermal performance effects than brown roofs.
In addition to that, green roof foliage offers better thermal performance by dumping the thermal effects of the solar radiation incident on the foliage that forms the roof. One of the factors used in the analysis of the thermal benefits of a green roof is to examine the temperature profile of a green roof. It is important to view the temperature profile of a green roof as graphically presented in graph 1 below:
Journal of Roof Consultants Institute, 2004
A graphical representation shown above displays the temperature profile of green roofs. Deducing from the above temperature profile, the accumulating effect is positive where the temperature of the green roof system indicates a rising trend (Cooper-Marcus& Barnes, 1999).
According to Cooper-Marcus and Barnes (1999), some of the important benefits realized from green roof include the effect of reducing the amount of greenhouse gas emissions into the environment. Asner,Scurlock and Hicke (2003) have examined in detail one of the methods of reducing the effects of carbon dioxide on the environment and have found that the strategy for reducing CO2 emissions is through the sequestration of carbon.
From a practical point of view, green roofs have significant CO2 reduction effects on the environment. In addition, to that, space conditioning with an aggregate effect of reducing the quantities of CO2 gas emissions are some of the significant impacts due to carbon sequestration from the environment.
According to Taha, Akbari, and Rosenfeld (1991), different methods used to fulfill the effects of carbon sequestration are discussed later. One such is a built in method. The built in method for reducing CO2 emissions include preventing heat loss into the environment is due to the insulating effect on the environment. The results are a reduction of energy demanded in a building.
On the other hand, evapo-transpiration effects and the aggregate impact on the urban heat island effect are also experienced. Typically, green roofs plants work by absorbing heat energy from the sun when exposed to solar radiation. As night approaches, the environmental temperature drops significantly leading the plants to radiate the absorbed heat during the day.
However, it is important to note that the thermal performance of a plant due to thermal stress experienced by plant membranes leads to the poor performance of the plant. The study indicates that membranes are damaged due to the whole cycle of absorption and radiation of solar energy from and into the environment Taha, Akbari & Rosenfeld (1991) and (Liu, 2002) through thermal stress.
Despite the ecosystem benefits gained from green roof systems, it is worth noting that the cost for developing ecosystems is prohibitive, and the structural requirements place further emphasis and further demands on the cost of developing a roof that can withstand the additional effects of green roof loads (Liu, 2002).
Quality of Water
Among the benefits realized from green roofs is the ability to retain high quality water captured from a green roof. The benefit due to the good quality of Water reinforces the rationale to construct a green roof.
Among the typical capabilities of green roofs is the ability to reduce the amount of load accumulating as contaminants from the roof through the water absorption and drainage ducts. That includes plant uptakes, evapotranspiration methods, and a variety of microbial activities. However, the green roof attenuation activities lower the concentration of contaminants through chemical and physical processes (Toronto and Region Conservation, 2006).
Another capability due to the green water conservation system is the ability to slow down the rainwater, an ability attained by slowing down the impact of falling raindrops, allowing the rainwater to percolate slowly into the roof, then into the filter and eventually into the drainage cell below. Typically, that is a strong structural benefit of green roofs compared with brown and conventional roofs (Saiz, Kennedy, Bass& Pressnail, 2006).
It is important to note that the aggregate effect of green roofs on runoff water and the chemical effects due to chemical pollutants significantly remain minimal in the process. On the other hand, leaching, one of the adverse effects experienced on green roofs occurs through the building materials used for the construction of green roof.
Overall effects include chemical contaminations particularly from treated materials such as timber used in the construction of green roofs (Toronto and Region Conservation, 2006). Analytically, it is important to formulate a mathematical model of the quality of water to allow its calculation assigned on numerical values.
Storm Water Management
Storm water management is one of the benefits realized from the construction of green roofs. Typically, the retention of runoff water is an additional benefit besides slowing down the speed at which rainwater penetrates into the ground, which helps to reduce the overall impact of rainwater and the resulting effects.
As an additional benefit in controlling the flow of surface water, the volume of restricted water flow on the surface has the overall impact of reducing the volume of runoff water and dissolved substances besides other runoff precipitates (VanWoert, Rowe, Andresen, Rugh, Fernandez & Xiao, 2005).
From the leaching effects due to runoff water, studies indicate that the amount of nitrogen leach decreases with time while phosphorous remains significantly the same. The chemical compositions are typically influenced by the amount of saturation in the target soil rainwater infiltrates the ground (VanWoert,et. al, 2005).
Mitigation of the Urban Island Effect
The urban island effect is the warming effect that causes urban areas to thrive at higher temperatures compared with their surrounding areas (Lundholm, 2006). The outstanding cause for the heat effect is the low reflectivity of urban areas, low vegetative cover, and the effect of arresting solar radiation due to the particles trapped in polluted air.
In addition to that, the “large amounts of heat released due to industrial activities, from buildings, and from automobiles contribute significantly to the urban island heating effect” (Morikawa, Takahasi&Kawamura, 1998).The overall impacts are adverse effects on human health and adverse environmental effects (Rosenfeld, Akbari, Bretz, Fishman, Kurn,Sailor, Taha, 1995) and (Bass,Krayenhoff, Martilli, Stull& Auld, 2003).
Other adverse effects include accelerated chemical activities such as smog and higher energy demands to cool buildings, which eventually increases the amount of CO2discharged into the environment (Morikawa, Takahasi&Kawamura, 1998).
On the other hand, an analysis of the behavior of vegetated surfaces indicates that cooler temperatures can be optimized the use of vegetation cover. Typically, green roofs provide cover and reduce the aggregate effects on the temperature of roofs thus reducing the heating effect of incident solar radiation on green roofs.
Air Quality
Another benefit arising from the use of green roofs is improved quality of air. The quality of air is attainable by the removal of dirt particles from the air by the filtering effect of plants. CO2, smog, and related discharges into the environment are some of the causes of global warming and the resulting detrimental effects. Typically, the removal of such dirt particles by the uptake mechanism of plants and through contacts (Grant, et al, 2003).
Biodiversity Benefits
Cities develop and expand through a range of destructive effects on biodiversity. That causes significant losses of wildlife sanctuaries and plant habitats (Cottingham, Brown& Lennon, 2001). A green roof plays a critical role in providing sanctuary for wildlife and natural habitats. One limitation of green roofs is that they do not provide the kind of habitations typical of natural habitats.
However, the importance of green roofs as natural habitats for plant and animal life such as vertebrates cannot be underestimated. It is important, as an approach in keeping green roofs to discuss in details about the operation and maintenance of green roofs (Grant, et al, 2003). It is also important to present a comparative view of the advantages and disadvantages of green roofs from various perspectives.
Advantages and Disadvantages
The following discussion crystallizes the merits and demerits of the green roofs to inform any interested party on an appropriate choice of green roof to adopt when selecting a green roof to construct. Many authors have studied the advantages and disadvantages of both types of green roofs and established the facts here discussed.
Advantages of extensive green roofs
Extensive green roofs have characteristic advantages by being light in weight with little demands on additional reinforcements, thus making the overall cost much lower. On the other hand, extensive green roofs are generally suitable for large surfaces and have a dutiable inclination of 300(Grant, et al, 2003).
In addition to that, extensive green roofs are largely good for retrofit undertakings, are comparatively less expensive, take the natural aesthetics of the environment, and allow the growing of vegetation to occur spontaneously. Detailed research into the benefits of green roofs indicates that they require less technical expertise and approval by various government authorities are easy (Dobson, 1995).
Disadvantages
Extensive green roofs have various de-merits due to the use of limited varieties of plants and are less appealing aesthetically. In addition to that, extensive green roofs provide limited or no access to public recreations and are less thermal efficient and diminishing water retention abilities (Grant, et al, 2003).
Advantages of intensive green roofs
Extensive green roofs have the advantages of the ability to accommodate diverse biodiversity and wildlife, have good thermal insulating properties, have the republication capabilities of natural habitats, and optimize membrane lives. In addition to that, intensive green roofs have greater capacities to retain storm water, higher energy efficiencies, and are flexible in meeting the aesthetical requirements of a green roof. A typical benefit of intensive green roofs is that they fulfill recreational needs of a city (Grant, et al, 2003).
Disadvantages
Intensive green roofs lay greater structural demands due to higher weight loads. In addition to that, intensive green roof systems lay additional irrigation and water requirements therefore leading to higher energy consumption. On the other hand, intensive green roofs require higher capital investments and require constant maintenance, are more complex, and require technical expertise in their design and construction when compared with brown roofs (Cooper-Marcus& Barnes, 1999).
Challenges
This discusses in details the challenges that the current generation is facing particularly due to high levels of carbon emissions into the environment and methods that have been used to mitigate the effects of carbon emissions into the environment. One most important challenge is to mitigate the effects of CO2 a gas known in scientific cycles and now is common known as the gas that is the major cause of global warming and the devastating effects experienced.
On the other hand, governments and other sources on methods of reducing the emission of CO2 into the atmosphere have experienced many challenges. These include the impact on the environment due to climate change, a fact that is evidently affecting both developed and developing nations. A number of impacts due to climate change have already been evident in developing countries.
Among the effects are prolonged droughts due to rising global temperatures, which have changed rain patterns, unpredictable rain patterns, dropping sea levels, and floods besides other effects that have started appearing. On the other hand, developed nations have experienced high levels of pollution, smog and associated effects on the environment.
That has led nations to formulate policies to mitigate the effects of air pollution on the environment. One such method is to construct green roof on conventional roofs.
Pollution and CO2 Emission
In the modern age, pollution particularly due to emissions of carbon dioxide into the environment due to industrial and human related energy consumption activities is a critical cause for concern for governments. An increasing body of evidence indicates rising levels of CO2 as one of the single most significant contributors to global warming with devastating consequences.
Countries, after the painful experience and anticipated effects of large quantities of CO2 in the atmosphere, have been compelled to lay strategies to optimize any available technology to curb and reduce CO2 emissions into the environment(Victoria Transport Policy Institute, 2011).
Scientists have established that CO2 emissions are a major global pollutant on a global scale. The polluting effects are both quantifiable and unquantifiable and present serious challenges to governments to search for ways to curb the devastating quantifiable and unquantifiable adverse effects (Grant, 2006).
Quantifiable effects include high mortality rates from the adverse effects of the CO2 pollutant, asthma attacks, and adverse effects on pulmonary functioning among others. On the other hand, unquantifiable effects include lung inflammations among others. Typically, these are adverse health effects (Victoria Transport Policy Institute, 2011) and (Oberndorfer, Lundholm, Bass, Coffman, Doshi, Dunnett,Gaffin, Köhler,Liuk & Rowe,2007).
Environmental effects have so far, by many researchers been identified to be the single challenge faced by many countries in the world due to large quantities of CO2 emissions into the environment. Over and above, these emissions result to climate change, commonly known as greenhouse gas effects.
Research into different emitters of CO2 indicates that motor vehicles are the greatest contributors of CO2 into the environment (Huang& Franconi, 1999). Various assessments by different governments conducted show detailed evidence on the risks and uncertainties associated with the impact on climate change.
Formal economic models used in the inquiry provide significant amount of data and information on the potential impact of global warming due to carbon emissions. Results of the studies estimate the overall impacts on costs associated risks to be 15% of the GDP of world countries, and expected to rise to 20% with associated rise in the impacts due to risks and costs (Kolb& Schwarz, 1993).
According to the Victoria Transport Policy Institute (2011) report, another challenge revolves around the contentions by other countries and firms, which contest fiercely that CO2emission does not have any impact on global warming. The argument is that little statistical data and scientific research show support for the argument that CO2 is the direct cause of global warming.
With the grim statistics promising worse eventualities in case CO2 emissions are not curbed, governments have to take it as an obligation to formulate methods to address the issue (Farzaneh, 2005). Governments, working with scientists and other experts have concluded that the effects of global warming are due to CO2 emissions and other pollutants.
In light of the results, policy formulations, carbon capture strategies, use of clean technologies, and in the more recent past, use of plants to reduce CO2 presence in the air particularly in the cities has taken the day. The following discussion provides views on climate change and government goals in mitigating the effects of CO2emissions into the environment (Victoria Transport Policy Institute, 2011).
Climate Change Mitigation & Government Goals
A report compiled by the Information Services of the UNFCCC secretariat (2007) shows that climate change results from the effects of CO2 emissions compelling countries to develop policies to address the carbon pollution issue. Estimates show that developing countries will require significant sums of money, in the tune of US $ 67 billion to address the effects of CO2emissions by 2030 (Information Services of the UNFCCC secretariat, 2007).
Governments have come up with strategies and set goals to mitigate upon the effect adverse effects of CO2emissions on the environment. It is important to note that developing countries are highly vulnerable to the effects of climate change. Typically, the social framework of the countries, political, and geographic orientation (Takebayashi & Moriyama, 2007) drives the vulnerability of each country.
Further, the Information Services of the UNFCCC secretariat (2007) is one particular approach used in the mitigation of the adverse effects of climate change and large quantities of CO2 emissions is adaptation. Adaptation allows human beings to change with the changing climatic needs and environmental demands.
That is particularly because the frequency with which the effects of global warming impact on the environment are increasing with time. Estimates indicate a drastic rise in global temperatures particularly in the last 25 years to be results of human activities such as the burning of fossil fuels (Information Services of the UNFCCC secretariat, 2007).
A diagrammatic representation of the effects of climate change and the chain of activities leading to the changes occur in the following discussion. There is significant evidence from the diagram showing that human activities are the prime causes of global warming (Wong, Chen, Ong & Sia, 2003).On the other hand, the diagram shows in detail climate change processes, the carbon cycle and resulting enhancement of greenhouse gas effects, and the resulting threats due to the human activities.
One of the main goals of many Governments is to formulate methods to address the emerging issues of climate change. These included cutting emissions to tolerable levels, encouraging personal responsibility in responsible use of energy, investing in research and development particularly by encouraging the use of clean technologies.
In addition to that, governments have endeavored to invest in research and development in the use of renewable technologies, and encouraging and investing in the use of plants to absorb CO2 from the atmosphere (Information Services of the UNFCCC secretariat, 2007).
Climate Change and Developing Countries
The impact of climate change and associated risks had most implications on developing countries. According to Grant (2006), developing counties experience different conditions with specific impacts on their environments. U.S. EPA (1998) and Gaffin et la, 2006 have established that the potential impact of climate change as being influenced by issues such as the geographical orientation of the specific country under consideration.
In addition to that, Gaffinet la, 2006 asserts that different measures specific-to-specific conditions of each country can be adopted to address the effects of climate change and particularly due to air pollution. On the other hand, Gaffinet la, 2006 and Hastaie (2000) have emphasized that climate change has wide-ranging effects on the environment, which include adverse effects on agriculture, socio-economic activities, and effect on rainfall patterns.
A summary of the negative effects of climate change are shown in the following figure along with other threats and consequences mentioned above (Grant, 2006) as illustrated in the fig 4 below
Grant, 2006
Among the changes observed due to climate change, based on the above diagram include greenhouse effects which result from CO2 cycles. These effects are directly due to urbanization, deforestation, transportation, agriculture, and many other sources. The potential impact of climate change processes include changes in precipitations, melting ice caps, average temperature changes, abrupt climate changes, and rising sea levels among other effects.
Gaffin, Rosenzweig, Parshall, Hillel, Eichenbaum-Pikser,Greenbaum, Blake,Beattie and Berghage (2006) have studied in detail the effects on carbon as one of the major causes of global warming and the need to mitigate the polluting effects on carbon in the environment. Among the causes are an increasing number of effects such as rising global temperatures, rising levels of smog, and adverse health implications.
According to Grant (2006), typical of the effects that come with rising levels of temperatures, include rising sea levels threatening cities lying close to the sea. In addition to that, climate change is bound to come with unpredictably harsh weather conditions and unpredictable surging level of storm, situations evidently observed in the recent past.
Developing countries are the main cause of geographic distributions of diseases, typically interacting with other vulnerabilities particularly malaria and HIV/AIDS, lowered life expectancy, and threats from the impact of prolonged droughts.
A study by U.S. EPA (1998)shows that climate change subjects the highly vulnerable natural habitats in developing countries to extinction with adverse effects on the entire ecosystem. Some of the effects include rising water levels. In addition to that, developing countries are susceptible to a decrease in annual precipitation, destruction of the terrestrial ecosystem, and rising temperatures consequent of the effects (Gaffin, Rosenzweig, Parshall, Hillel, Eichenbaum-Pikser,Greenbaum, Blake,Beattie& Berghage, 2006).
There is need for developing countries to plan for sustained development and invest in capacity building and capacity adaptation to the impacts of climate change. In addition to that, developing countries need to work with developed nations, non-governmental agencies, and other organizations to plan and strategies on the best approaches to minimize the impact on global warming (Emmanuel, 2005). A typical example of a country affected by CO2 emissions is Iran, and particularly the city of Tehran, as discussed below (U.S. EPA, 1998)
Tehran Case Study
A study by Asadollah-Fardi (n.d) shows Tehran as one of the most heavily polluted cities in the Middle East. AccordingAsadollah-Fardi’s (n.d) study, one of the contributing factors to the high levels of pollution include the dense population estimated at 10 million people whose energy intensive activities lead to high CO2 emissions.
The similarity of the city’s geographical orientation to that of other cities such as Los Angeles in USA contributes to the study. Due to its topological orientation, the city does not experience any flow of wind as either parts of the city surrounded by mountains capped with ice. Restrictive movements of the wind on the city are one of the contributing factors to high thermal concentrations within the city.
In addition to that, the restricted movements of the wind over the city denies it the benefits of moving dirty air out of the city casing a further rise in pollutant concentrations with the consequent destructive effects (Asadollah-Fardi,n.d).
High pollutant emissions are a direct result of burning energy from the environment. In addition to that, a growth rate of emissions experienced in the recent past due to ever-increasing number of vehicles on the roads has been recorded (Asadollah-Fardi, n.d). To compound the seriousness of the pollution problem, climatologically factors have shown significant contributions, making the city to suffer from higher ozone levels and associated effects (Hastaie, 2000).
Further research shows that obsolete machines due to the long standing economic and technology sanctions have made the situation worse. Other contributing factors are a rising number of private vehicles on the roads, poor urban planning methods, poor vegetation cover within the city, cheap and poor quality fuels, and a rising population with social and economic consequences (Hastaie, 2000).
Among the mitigating strategies laid by the Iranian government to curb the rising levels of CO2emissions, include conducting inspections on vehicles in use, active participation in international forums on the reduction of the greenhouse gas emissions, using solid waste management technologies, relocating industries besides investing in to develop green spaces.
Green spaces include the planting of tress as analyzed in the following section (Asadollah-Fardi, n.d). In order to lay strategies for mitigating the impact on the environment due to pollution effects, an environmental committee constituted the elements as illustrated below with the main goal of looking for strategies to curb urban pollution (Hastaie, 2000) as illustrated in the chart 1 below.
The theoretical framework upon which the inquiry relies focuses on the CO2lifecycle within the plant system and within the environment. These studies rely on effects caused by plants and their overall effects on the environment especially in relation to the control and emissions of CO2.The study examines the option of using green roofs as pollution mitigation methods based on the carbon flow lifecycle in plants since these plants can grow on these roofs.
According to studies based on the carbon lifecycle, carboxylation of CO2 is a process that works through the acceptor molecules by reducing component substances into two separate molecules. Typically, the process takes place in the plant in the form of advanced or primitive forms. The process fixes CO2into other systems as one of the metabolic processes.
The fixation of CO2 in plants is one of methods used to control and amount of CO2 emissions into the atmosphere. Typically, that is a carbon management strategy integrated into green roof systems. Many researchers have studied the benefits gained from green roof systems based on different models.
These benefits have led to the conclusion that constructing green roofs into conventional roofs has shown significant energy reductions with a 2% reduction in energy consumption and a 9 % decline in the overall consumption of natural gas within a building. In addition to that, other benefits include lower greenhouse gas effects, which calculations estimate at 702 g C per m2.
Other studies however show that the carbon costs incurred during the construction and installation of green roof systems could take a significant period to offset (Getter et al, 2009). This study examines the theoretical framework upon of the carbon lifecycle is studied and the use of green roof systems as a pollution mitigating measure.
Plants and CO2 Emission
Different studies on the vegetation cover in many cities shown that much of the cover consists of exotic plants and native plants. In addition to that, green roofs in densely populated areas in certain sections of different cities with a diversity of trees, contribute to the preservation of wild life and other animal species. A spot check of one of the cities in North America shows a variety of tree species prevalent in the region as tabulated in table 5 below.
Table 5
Common Name
Percentage population
Percentage leaf area
IV
European Buckthorn
23.3
5.5
28.7
Norway Maple
6.0
21.2
27.2
Box elder
11.0
12.1
23.1
Green Ash
12.7
8.8
21.5
White ash
4.7
4.9
9.6
Sugar Maple
1.6
3.0
4.6
Sources: Urban Forest Effects and Values, 2008
Several studies by many researchers to understand the effects of plants and their overall implications on the environment in relation to CO2 emissions have yielded several of results. These studies show how the problem associated with CO2 is to the environment. Thus, it is important to examine the mechanism through which plants interact with CO2 in their intake and discharge of the gas into the environment and their contribution to reducing the gas (Lee& Kim, 1994) and (Hartig, Mang& Evans, 1991).
Typically, green roofs offer a strong promise on the reduction of CO2 emissions into the atmosphere. Therefore, it is important to look at the theoretical processes through which CO2 is absorbed and discharged into the environment. To understand the rational of using plants as one critical approach to address problems of pollution, which lead to global warming, Theodosiou (2003) has examined the issue in detail.
From a theoretical point of view, CO2 reactions take place in the environment through photosynthesis as illustrated below.
Photosynthesis: Carbon Reactions, n.d.
Theoretically, the conceptual framework modeled after the Calvin cycle shown above shows the carbon cycle. Typically, the cycle consists of three steps. Carboxylation starts the first cycle of the whole process, followed by the second reduction step in the cycle and concluded with a regeneration process (Photosynthesis: Carbon Reactions, n.d).
In the cycle, carboxylation of CO2 works in tandem with the acceptor molecules reducing the component substance into two separate molecules. Typically, the process occurs in all forms of vegetation in their advanced or primitive forms. The process leads to the fixation of CO2inone of the metabolic processes (Photosynthesis: Carbon Reactions, n.d).
Water and CO2 fixations into the atmosphere are a process that occurs through enzyme activities resulting into two molecules mentioned above. 3-phosphoglycerate resulting from the process is further reduced by substances generated photo-chemically into carbohydrates leading to a further generation into 5 more CO2 acceptor molecules at the end of the first phase. Several other chemicals cooperate in the process (Photosynthesis: Carbon Reactions, n.d).
In practice, during photosynthesis, plants take large amounts of CO2 from the atmosphere and release it later by burning it. When the amount of CO2 released into the atmosphere and absorbed from the atmosphere is similar, a biotic balance is established. However, when both the absorption and release of CO2 is not balanced, there is no biotic equilibrium, creating regions of carbon sinks as has been experienced in cities (Photosynthesis: Carbon Reactions, n.d).
A study by the Photosynthesis: Carbon Reactions (n.d) paper reports that various plants show significant changes with changes in the environmental. As environmental conditions change, most plants indicate an adjustment in their uptake mechanism. One important point about plants is that they have an inbuilt mechanism of adjusting to increasing amounts of water and CO2uptakes from the atmosphere, a very critical point when establishing a green roof.
Plants convert CO2 into sucrose and other substances and keep the captured CO2 in that form for a long time. In effect, that is a strong point to consider when constructing a green roof as one of the critical environmental benefits. That achievement occurs by way of enzyme reductions and other forms of reactions involving the absorption and conversion of CO2 into different forms.
That makes it important to translate the above theoretical conclusions into practice to help answer the inquiry on the role of plants in reducing CO2 emissions into the atmosphere and gradually reduce global warming (Earth Pledge, 2005). One argument in favor of the use of plants and pointing to their role as CO2 management approaches is that plants have an integrated mechanism that allows them to adjust and adapt easily to climate changes (Photosynthesis: Carbon Reactions, n.d).
Another argument is one that views plants as being able to adjust to upward temperature changes due to global warming by changing their perspirations accordingly. In addition to that, plants correspond to carbon releases by decreasing the amount of CO2released due to climate change. Typically, the characteristics of the plants are a deciding factor when selecting the type of soil to use in creating a green roof (Theodosiou, 2003). According to Theodosiou (2003), the families of plants also influence the level of carbon emissions into the environment.
Green Roofs and CO2 Management
Stabilizing the amount of CO2 emissions into the atmosphere is critically important particularly in cities with high population densities and high levels of carbon emissions. Among the methods used to reduce the amount of CO2into the environment, which is, also a carbon management strategy is the use of green roof systems (Trumper, Bertzky, Dickson,van der Heijden, Jenkins & Manning, 2009) and (Del Barrio, 1998).
Researchers and scientists have proposed many approaches of reducing CO2 into the atmosphere. Two of the methods include reducing the amount of CO2 discharged into the environment or increasing the absorption rate from the environment. While different approaches in addition to the supporting policies on carbon management are in place, their effects have not caused significant impacts in reducing the effects of air pollution on the environment (Trumper et al, 2009).
Thus, the need to use green roof as a pollution control mechanism is overwhelming. Among the areas that green roof systems have found significant use are in cities. The use of green roof systems is a good option since it is a proven and successful technology in reducing CO2emissions into the environment(Goward, et al., 1985). Typically, the reason for use in urban areas has been primarily that these areas suffer heavily from high-level concentrations of CO2 due to industrial activities and high population densities (Trumper et al, 2009).
One of the methods generally accepted as a carbon management strategy is a well-designed green roof system. A green roof is a natural a carbon management approach that comes with a significant number of environmental benefits. One benefit of green roofs is due to the characteristics of the ecosystem. Research has shown that a wide biodiversity of plants on green roof systems offers ecosystem services.
These include the capacity to store large quantities of carbon depending on the characteristics of the plants grown on the green roof (Liu, 2004). To optimize the use of green roofs for the capture of carbon and as a carbon management strategy, low growing plants the roofs attain that goal. In addition to that, plants with a low growth rate and low decomposition rates are used (Trumper et al, 2009; Villarreal& Bengtsson, 2005).
On the other hand, restoration of the degraded environment usually contributes significantly in reducing the amount of CO2 emissions into the environment Getter& Rowe, 2006) and (Boivin, Lamry, Gosselin &Dansereau, 2001).
Estimates indicate that a carefully designed and installed green roof has the capacity to capture large amounts of CO2 and restrict the discharge and exit of CO2 into the environment from buildings insulated by the green roof. Calculation indicates that close to 55,000 tons of CO2 can be captured using green roofs in an area equivalent to one million people.
However, recommendations on a further study on carbon quantification and the overall impact of a CO2 management strategy be done and the results from such a study examined to further inform the inquiry (Trumper et al, 2009). The results are based on a research conducted on different types of green roofs, different plant specifies, resulting biomass, and conducted on different locations as tabulated below (table 2) (Theodosiou, 2003).
Different species planted on each plot of the green roof had different characteristics. These included the variants of sedum including the acre, spurium Bieb, sedum, and album species. The seeds, carefully germinated to grown over a number of years provided good plants. Maintenance activities for the green roofs should be carried out at regular intervals on a three months period cycle.
Maintenance included roof irrigation to keep the water saturation levels in the soil to established standards, and weeding done according to requirements (Trumper et al, 2009). Many samples taken and analyzed from the proposed site provided a series of results. The samples collected and analyzed from the roofs to evaluate the carbon sequestration “a process through which CO2 is removed for the atmosphere by plants” (Trumper et al, 2009) by the plants grown on the roofs in the proposed area.
The procedure included removing the roots from the soil sampled for examination to determine the amount of CO2 sequestration. In addition to that, the roots pulverized into powder before analyzing for carbon content in the plants (Trumper et al, 2009). It was also important to determine the level and amount of carbon per a given unit area. The procedure used an ANOVA model in the study as detailed in table 6 below.
Table 6
Date originally planted
Location
Comment/Comments
CA2.5
May 2005
9/6/2006
Michigan State University (MSU), Communication Arts (CA) Building, East Lansing, MI
Research plots are placed directly on roofs. Primary species included S. album, S. middendorffianum, S. sexangulare, and S. spurium.
CA3.2
May 2005
9/6/2006
MSU Communication Arts Building, East Lansing, MI
Research plots placed directly on roof. Primary species included S. album, S. kamtschaticum, S. middendorffianum, and S.sexangulare.
FORD
Fall 2002
9/1/2006
Ford Motor Company (FORD), Rouge Plant, Dearborn, MI
4047 m2 extensive green roof. Primary species included S. acre, S. album, S. kamtschaticum, and S. middendorffianum.
HTRC2.5
June 2003
9/5/2006
MSU Horticulture Teaching and Research Center (HTRC), East Lansing, MI
Roof platform. Primary species included S. acre, S. album, S. middendorffianum, and S. spurium.
HTRC5
June 2003
9/5/2006
MSU HTRC, East Lansing, MI
Roof platform. Primary species included S. acre, S. album, S. kamtschaticum, S. middendorffianum, S. reflexum, and S. spurium.
Rahshahr International, 2011
After conducting a study of the family of plants suitable for green roofs, it is important to discuss the potential benefits (Baumann, 2006) as illustrated in table 7 below.
Table 7
Roof
Substrate depth
Age sampling
Plant carbon
CA2.5
2.5
15
97±27.9
CA3.5
3.2
15
127±19.0
FORD
2.5
39
196±64.8
HTRC2.5
2.5
39
144±16.0
HTRC5
5.0
39
159±32.4
HTRC6
6.0
52
224±52.6
HTRC7.5
7.5
53
202±11.1
MDG
7.0
28
73±16.0
MF
7.1
53
89±33.5
RC
6.4
48
276±28.0
SEV
10.8
4
112±30.1
Roof
Substrate depth
Age sampling
Plant carbon
CA2.5
2.5
15
97±27.9
Liu and Minor, 2005
The amount of carbon capture with age and substrate depth considered in detailed in the study are shown above. However, the amount of carbon capture depends on the age and species of the plant. On the other hand, the amount of carbon above the ground varies with each species. Despite that effect, the overall findings concluded that different plant species contribute different amounts of carbon emissions with different carbon concentrations in a given quantity of waste missions (Getter, Rowe, Robertson, Cregg& Andresen, 2009).
Tabulated data from the above table shows the potential benefits of the relative amounts of CO2 captured and the benefits from each type of green roof system(Givoni, 1998). In addition to that, the results based on practical findings show the lowest level of carbon sequestration to be 73±16.0 while the highest benefit registered was 276±28.0. The mean value obtained from the results was 162±11.7 indicating a standard deviation from the mean to be small from all the samples (Getter et al, 2009).
Conclusions from the study show that green roof systems generally have a carbon sequestration rate of 375 g C·m−2 which is an accumulated value for above ground and biomass substrate carbon content. Noteworthy, it is important to note that a significant number of components that make up a green roof system experience a carbon cost in the production process (Getter et al, 2009).
A critical analysis of green roof systems of the constituent components shows that a green roof should incorporate a barrier to the roots on the roofing system. That is particularly the case to prevent damage from the roots that might penetrate into the roof. Other costs associated with the roofing system are maintenance and regulation of water flow in the roof and additional carbon costs due to the gravel used on the roof (Getter et al, 2009).
On the other hand, irrespective of the amount of energy consumption of the roof system installation and maintenance carbon costs, the benefits outdo the carbon costs mentioned above (Liu& Minor, 2005).
Different researchers have modeled further studies on the benefits of green roofs. Deductive conclusions from such research show that constructing green roofs into conventional roofs have registered an estimated 2% reduction in energy consumption and a 9 % decline in the overall consumption of natural gas within a building. The benefits include lower greenhouse gas effects, estimated at702 g C per m2.
On the other hand, calculated estimates show that the carbon costs incurred in the construction and installation of green roof systems could take a significant period to offset, about nine years (Getter et al, 2009). Further research into the benefits and capacity of green roof systems for use in carbon management shows that they are empty spaces exploitable for good use to sequester carbon emissions.
Different cities have developed green roofs covering different surface areas. A typical example is Detroit Metropolitan region. Estimates show that the total area under green roofs in Detroit is less than 8399 ha. At the sequestering rate of 375 g C·m−2for green roofs, it is estimated that 55, 252 tons of carbon can be sequestered in a year, which is an equivalent of emissions produced by 10, 000 midsized trucks in a year (Getter et al, 2009).
It is worth noting that the above findings were susceptible to the orientation and design of a roof system. In addition to that, climatic characteristics of the locality in consideration exert a strong influence on the results on carbon management.
Methodology
The research methodology included a literature review of various perspectives and research by on literature by different authors on different categories of green roofs. The review mentioned three categories of green roofs including intensive, semi-intensive, and extensive green roofs. However, the research focused more on intensive and extensive green roofs in informing the research.
Various issues researched while conducting the literature review to inform the research included a history of green roofs, classification of green roofs, construction methods, types of green roofs, benefits particularly environmental benefits of green roofs, and narrowed down on Iran as a case study. In addition to that, the role of plants in carbon management, carbon costs, and carbon management benefits derived a practical and analytical study of different types of green roofs and carbon management approaches and findings(Wellburn, 1990)
From a practical point of view, the research focused on an airport proposed for construction near the imam Khomeini airport in Tehran. The aim was to make the project zero carbon rated in terms of emission into the environment. Typically, it was to serve a pilot project to provide required and detailed data characterizing a typical concept of a pollution control mechanism due to roof green systems (Köhler & Keeley, 2005).
One approach used in the study was a regional analysis of various issues such as the level of saturation in the soil, targeted for the construction of the proposed IKIA site. Various issues, with particular contribution to carbon emissions and other pollutants into the environment formed part of the study.
A site analysis was one of the critical elements contributing to the flow of air from and into the city, the level of pollution due to CO2 emissions, and the percentage carbon reductions achieved. On the other hand, a detailed study of the type of green roofs worth constructing at the site as a pollution mitigating strategy formed part of the study. In addition to that, the study details the family of plants that to plant on green roofs, and the level of CO2 reductions attained from the use of the plants.
A document analysis of details about the climatic conditions prevailing at the proposed site for the construction of IKIA airport have been examined in detail to inform this study. Further research conducted into landscape design and the overall effects on the carbon management and contributing elements such as the orientation to the sun, wind and soil characteristics, and saturation of water in the soil.
Case study result
An analytical study of the proposed area for the construction of the airport facility starts with a summary of the location of the proposed site, the weathers, flora, the fauna, site information about the plants growing at the site, and the available plants. Site characteristics include a close examination of the topological features that are prevalent on the northwestern part, which is dotted with small hills that are insignificant in terms of airflow control.
In addition to the studies concentrated on the southwestern side slopes with 5% of the land mass with an aspect on the windward side examined in the study. On the other hand, an ecological report which played an important role during the decision making process on the type of plants to grow to achieve zero carbon level carbon emission, a goal that may not be achieved in practice is discussed.
Other issues discussed in the report include the climate of the region and the bio-climate, which falls into the geo-botanic category prevalent on an arid-north climate and lies between Artimisia, Astrugalus genera, and Afghan-Anatol steppes.
The aim of the study is to provide detailed information to enable decision making on the use of green roofs as a carbon management method and a method to mitigate upon the effects of carbon related pollution, with Tehran, Iran as the case study.
Site Characteristics
The topology of the area, the direction of the wind, the location of the site, the source of electrical power, industrial centers, residential areas, usable areas, and zoning for flight routes examined to establish the carbon generating activities and the use of appropriate green roofs as a carbon control mechanism.
The site survey showed Tehran to sit in a semi-arid area, with much of the land showing a high aspect to the sun as an additional benefit to tap into the solar energy. A critical evaluation of various zones showed the western and Northwestern zones to be appropriate for supporting non-pollution activities. In addition to that, the Northwestern side proved highly dominant from the wind.
The Rood Shoor River bound the southern part with little ecological significance with some areas registering a slope of 5%although other areas register deeper gradients not fit for civil works. Deep gradients occur along the Southern boundary. To evaluate the site further, a significant portion of the region is suitable for civil works while alluvial deposits not suitable for civil works dominated the rest of the site. The Shoor River binds much of the useful areas.
Important reports show that some parts of the southwestern part overlapped with small geological fault lines dominated by alluvial deposits along the Riverbeds that are susceptible to liquefaction, emphasizing the need for buffer zones. On the other hand, the Southern part is highly susceptible to quick erosion with good water shed development capacity (Givoni, 1998).
A close study of the topological features shows the northwestern part to be dotted with small hills that have little significance in influencing the direction and speed of airflow. On the other hand, the southwestern side forms a slope of 5% of the land mass showing an aspect on the windward side. One feature dominating the northeastern part is a small water reservoir with a small catchment, which reduces the possibility of the likelihood of floods occurring.
On the other hand, the northeastern part dominates excellent soils, which are quite good for agricultural purposes while the rest of the land dominating arid and semi-arid landmasses. River Rood Shoor presenting little risks from floods with little ecological significance dominates the southern part. Further analysis of the site shows the region along which Rover Rood Shoor to be in a low-lying valley.
Statistical data shows residential areas to be Parand New Town with a population density estimated to be 40,000 occupants, Robat Karim City consisting of 750,000 occupants, and Hasan Abad city with 20, 000 people. Industrial concentrations are within the Parand Industrial Area occupying an approximate area of 210 ha, Parand Power plant, Tehran wheat distribution point, Nasirabad Industrial area, and Shamsabad Industrial Area occupying approximately 289 ha of land.
A summary of land use shows 7500 ha usable land of a total 13750 ha. In addition to that, a survey of the airport and land possibility of noise pollution shows different areas conforming to different noise level standards and zones. Zoning of noise levels with areas classified with a range sound below 60 dB, 65dB, and 70dB with respective activities conforming to the sound levels.
Typically, areas with sound levels below 65dB are equivalent to 6000 ha, below 70dB covered in equivalent to 7,200 ha, area with sound levels below 60dB cover a surface of 3,600 ha. In addition to that, the height of buildings is restricted due to flight of aircrafts.
Ecological findings
An ecological report was important to enable decision-making on the type of plants to grow to attain zero carbon emissions. In addition to that, the ecological report tables the findings about the ecology of the proposed site and the relationship between the plant species and the environment (Che-Ani, Shahmohamadi, Sairi, Mohd-Nor, Zain & Surat, 2009). According to Che-Ani, Shahmohamadi, Sairi, Mohd-Nor, Zain & Surat (2009), the ecological inquiry provides adequate information about the kind of roof to construction a particular area.
Ecological Characteristics On a larger Scale
The proposed area of IKIA airport lies in the Irano-Turanian area, which is with physo-geographical characteristics. It has abioclimate, whichfalls into the geobotanic category prevalent on an arid-north climate and lies between Artimisia, Astrugalus genera, and Afghan-Anatol steppes. In addition that, the region has low rainfall with 69% dominated by Irano-Turanian plants.
Its forest cover consists of a range of species including Juniperus, Hultemia persica, among several others on the Tehran side. On the other hand, the region split into nine sub regions with different types of vegetation cover typically classified into eight groups.
Meteorological Findings
Investigations into the climatic parameters of the proposed site reports an annual precipitation of 161.7 mm based on statistical findings over a long period of investigation. “Typically, the average precipitation for the entire country is 250 mm indicating the region to experience lower precipitations than the rest of the country with significant precipitate variability in the region”(Rahshahr International, 2011).
Statistical data shows that temperatures can rise to a high of 400centigrade and a low of -200 centigrade with a mean daily temperature with an estimated value of 17.70 C. The region suffers from frost occurring between mid-Octobers to late April peaking in January with an average occurrence of 60 days for the year. The six of the remaining months do not experience frost.
Reportedly, the highest precipitation occurs between December and February with dry air occurring in the months of May and September with July registering the lowest precipitation. The availability of ground water is an additional element in the region. A hydrological report shows Karaj and Zarand-Zaviye to be hydrological sources of ground water. The relative amounts of ground water from both hydrological sources put in table 8 below.
Table 8 soil characteristics
Auriferous Plain
Ground water level(m)
Thick alluvium (m)
Capacity Transmission (m2/day)
Tehran-Karaj
Min
Med
Max
Min
Max
Min
Max
Min
Max
5
20-70
130
50
200
100
4000
2
20
Zarand-Zaviye
5
–
20
20
–
–
–
Med
3
Rahshahr International, 2011
Soil Resources
One important aspect to consider when constructing a facility with zero carbon emissions is to examine in detail the characteristic of the soil that supports the vegetation intended to help to reduce carbon emissions. Much importance related to the percentage use of soils and land resources. Land use contributes a significant amount of carbon emissions into the environment due to the energy intensive activities (Foxon, 2002).
A survey of the land shows the land to fall into three regions. These include hills, which form the major feature in the region, plateaus, and alluvial plains and other characteristic features illustrated in table9 below.
Table 9 Land descriptions
Land Type
Land unit
Land unit description
Limitations
Hills
2.4
Dissect low hills, slope 20-80%.
Elevation 1500
Topography and erosion, soil salinity, and soil properties limitations
Plateaus
3.1
Overall, slope less than 5%.
Topography and erosion properties
Piedmont alluvial plains
4.5
Piedmont plain with gentle slopes, slopping at 1-5%
The basic carbon generating activities, which are highly dominant in the proposed area, include agricultural activities and emissions due to airport activities such as aircraft and motor vehicle emissions. The rest of the land is either bare and of little or no use and is characterized by consisting a range of rocks and moderate ranges. The biological environment provided information about the appropriateness and strategies to reduce carbon emissions and falls into prevalent vegetation, plant types, and wildlife.
The Biological Environment
The area is deficient of tree cover and severely limited to a specific range of species. Artemisia seiberi is one type of plant that thrives on a surface area of 19,000hectares, with an elevation of 1000 m. In addition to that, the plant thrives in semi-desert areas. On the other hand, Artemisia seiberi- Pteropyrum sp. dominates a land cover of 52,000 ha with its variants.
Other species include Artemisia seiberi- Stipa sp that covers an area of 111,000 ha (Severinsen & Jager, 1998). Further research on the biological environment showed that the regional wildlife contributes significantly to the beauty and attraction of visitors into the area. Mammal species are 42 in number constituting 15 family species. Birds, on the other hand, contribute 122 species belonging to 31 families, each contributing a specific amount of CO2 to the environment.
However, it may be difficult to quantify the amount of carbon emission into the environment due to the wild life in the area. Further still, nine families of reptiles are distributed the area consisting of 24 species. The distribution consists of amphibians and two species of fish. It is important to conduct an investigation into the ecological effects of protected areas and gradually the carbon emission contributions into the environment.
Typical areas under protection include Alborz, which is 23 km aerial distance. Kavir, which is located at a distance of 12 km of aerial measurements is a protected area and connects with jajrod. Typically, these areas are constituents of the satellite areas with ecological characteristics disconnected from each. The jajrod area measures close to 56625 hectares and has many mountains and hills covering the entire region.
In addition to that, the area experiences the effects of Roheden Rivers that passes through it, particularly in the eastern part of it. With an average temperature of 11 0C and an elevated area of 1150 hectares, the region experiences an average precipitation of 275 mm influencing the overall climate to be semi-arid to an arid area.
The attributes of the area are high concentration of biodiversity with 517 species of plants. In addition to that, animal species identified in the area count up to 192 animals with a concentration of the Astraglus and Artemisia tree species. Each of the animal and plant species contributes significantly to carbon management in the area. Moreover, it is important to note that the area is close to Tehran, the area proposed for construction of the new airport facility.
Another area of interest worth investigating is Kavir, one of the protected areas around the Tehran area. Located in the Ghome salt lake area and covering an area equivalent to 248957 hectare, the protected area covers three administrative provinces managed as a national park area.
Additional features of the area show plain like features with a temperature range of 10 to 25 centigrade and an elevation varies between 740 and 1360 meters. On the other hand, the precipitation level is 132 mm. The ecosystem is a landscape of swamps, salt ecosystems, and desert landscapes.
Location
The proposed site has a location, which is a hybrid between the industrially developed urban and agricultural region, which lies to the North of Tehran and Qom salt lake, and the desert region, which is largely a wilderness area. From a topological point of view, the area is approximately 1000 meters above sea level when measured from the eastern side.
Further topological results show the area to be flat with significant slope variations. The sloping of the landscape varies between 10 and 15%, with an average slope of 5% in the region. On the other hand, the greater percentage aspect of the area is towards the eastern side with the rest of the area presenting a clear view from different directions.
The area enjoys an annual precipitation of 161.7 mm compared with the prevailing annual value of 250 mm. That classifies the area into the category of a low rain receiving area and cold arid climatic characteristics. A critical analysis of the ambro-thermic diagrams reveals the region dominated by arid conditions with five wet moths in a year (Grime, 1998).
Wind strongly influences the flow and direction of the movement of dirt and smog particles in the air. The direction and speed of wind is therefore an important element to consider when setting up a city. Typical of the area under consideration is the wind speed and direction. The area experiences a wind flow of 23 knot (11.5 m/s) in the westerly direction (Hanson& Lindberg, 1991).
On the other hand, the Robat Karim and Shoor Rivers are the dominant rivers that within the region with the Shoor River being the most important of the entire Rivers in the region. However, no significant agricultural activities are suited to the salt water from the River. A distinguishing characteristic of the Shoor River is that it remains dry for a significant part of the year, though it receives water from many tributaries.
On the other hand, it is clear that underground water is unsuitable for agricultural activities as it maintains high levels of salinity (Gaffin, Rosenzweig, Parshall, Beattie, Berghage, O’Keeffe&Braman, 2005). The Kahrizak geological formation is especially of much importance with its lithology characterized by interacting sandstones, clay, and other conglomerates.
Activities that lead to the consumption of energy and eventually leading to high levels of carbon emissions within the region include airport activities and other land use activities. The region suffers from limited precipitation, consists of 42 mammal species,2 amphibian species, poor vegetation cover, saline underground water, and significantly low support to life and biodiversity.
Regional Analysis
A regional analysis of the proposed site informs the study of various issues such as availability of agricultural land. Agricultural land is under increasing threats from a rapid rate of urban development particularly from the construction industry and associated carbon emission due to energy consumption (Korhonen, 2005).
The diagram below shows the most suitable location of the proposed facility and the topological details on of the region. The main factor considered here are the settlement areas, wind flow, and proximity of the area to the mountain range and Parand town that provides some suitable perspective for the growth of the town.
Table 10 Area and land use
Land use
Code
Number
Area (m2)
%
Per cap. (m2)
Residential
Residential
102
602
146003.21
0/29
46/04
House garden
103
7
88935.14
18/0
05/28
Residential assembly
104
2
76966.93
15/0
27/14
Total
611
311905.28
62/0
36/98
Educational
Elementary school
202
7
10260.69
02/0
24/3
Total
7
10260.69
02/0
24/3
Higher educational
University
302
3
1281422.26
57/2
11/404
Total
3
1281422.26
57/2
11/404
Administrative
6
5
27473.89
06/0
66/8
Imam Khomeini Cultural & Religious assembly
7
1
69/1488358
99/2
37/469
Religious Aftab
8
11
63/32564
07/0
27/10
Disciplinary-Military
10
6
22/717870
44/1
39/226
Commercial
12
38
06/81162
16/0
60/25
Public utilities
13
43
21/52602
11/0
59/16
Urban installations
14
11
93/360405
72/0
66/113
Transportation & Warehousing
15
42
18/650262
31/1
07/205
Cemetery
16
2
35/4339
01/0
50/1
Sanitary& Health
17
2
79/4761
01/0
50/1
Industrial-Manufacturing-Repairing
18
123
45/535839
08/1
98/168
Animal husbandry
19
68
11/478204
96/0
81/1580
Agricultural
503
—
78/28372398
94/56
46/8947
Horticulture
402
50
88/1295229
60/2
46/8947
Road network
21
—
35/296485
10/13
61/2057
Sporting &Recreational
22
1
38/2245
005/0
71/0
Social Services
23
1
36/1186
002/0
37/0
Green space
Public green space
401
61
69/482599
97/0
19/152
Protective green space
403
207
34/5862632
77/11
83/1848
Other land uses
Under construction
501
4
68/70543
14/0
25/22
No land use
502
—
56/395005
79/0
57/124
Ruined & Obsolete
504
55
87/201586
40/0
57/63
Stream & River
505
—
1/187136
38/0
01/59
Lands by the streams
506
—
16/392493
79/0
78/123
Grand total
—
—
49825183
100
—
To further analyze and inform the study, an analysis of the water flow and flood control and their effects in the region show the area to be earthquake prone with the highest risk being a high potential of floods from the streams of water that pass through the region. On the other hand, the liquefaction potential varies with each locality.
The eshtehard region is susceptible to a high potential of liquefaction while the rest of the region experiences frequently occurring liquefactions, which at other places occurs without notice. On the other hand, IKIA suffers from a combination of frequent liquefaction to no liquefaction at all. The following table illustrates the findings around the IKIA region in table 10 shown below.
On the other hand, a close study of the region shows that the region experiences solar insulation varying between the surrounding regions with varying intensities. Thus, the solar down gradient varies between 5000 and 5500 with IKIA lying in the above-mentioned solar gradient concentration.
Analytically, the climate of IKIA region is partially pleasant. The yearly cooling energy needs vary from mild levels, temperate, warm, and hot. Typically, cooling energy needs demands for a rise in energy consumption causing a rise in carbon emissions into the environment. On the other hand, energy requirements based on yearly heating needs vary between cold, ultra cold, and frost levels.
Each of the heating needs consume specific quantities of energy resulting from the burning of carbon and leading to carbon emissions into the environment. Historical sites and artifacts provide a basis for tourism and associated energy consumption and carbon emissions. Historical artifacts cover prehistoric, historical, Islamic, and non-specified historical attractions.
Another important factor contributing to carbon emissions is the trend and rate of population growth. A critical analysis of the population growth and trend shows an outwards inter-state migration trend driven by the availability and distribution of job opportunities, a major factor in attracting large population growth into Tehran city. The population growth and distribution is thus concentrated in the urban areas around Tehran.
That has changed the status of certain cities to principal cities and province centers. Typical examples include Qazvin and Qom. On the other hand, the railway network provides an enabling environment as a good communication network for the proposed construction site. The following illustration provides a clear view of the proximity of IKIA to other centers for cargo and other transportation needs (Felson& Pickett, 2005).
A review of cities in proximity of the proposed site with carbon emitting activities, which cause air pollution, is worth analyzing. One of these towns is the city of Aftab. Aftab is located in the southern part of Tehran with a total surface land area estimated at 4689 Hectares. When put to use, estimates show that the area can support 56% of the total surface area dedicated to green space.
On the other hand, Aftab has an area allocated to land use for exhibitions measuring 211 hectares. The 211 hectares are only 4.55% of the total land area proposed for use (Hien, 2002). Other uses of land include residential areas for hotel apartments constituting approximately 2.33% of the total proposed land use. Estimates show the total residential land can accommodate about 1200 residential units with an estimated capacity of five thousand people.
In addition to that, additional features include residence for college students estimated at 80,000 students. Many of the land use activities are according to the estimates summarized in the table above. It is important to conduct an analysis of the ecological footprints associated with each carbon and other pollutants generating activities (Dunnett& Kingsbury, 2004).
Typically, the ecological footprint provides estimates of the amount of consumption energy in each sector. The service sector is estimated to consume energy estimated between 1.43 M.J and 107 552 milliards MJ. On the other hand, per capita consumption specific to areas susceptible to flooding is 230906 MJ, which contributes an energy estimated at 30.787 MJ in the areas of crop production, among other agricultural activities.
In addition to that, estimates of per capital consumption of energy are in the range of 143 million GJ equivalents of 1.43 hectares (Durhman, Rowe, Ebert-May& Rugh, 2004). Estimates show over 171 million m2 surface area to be under houses, a significant source of air pollution into the environment due to energy consumptions. Further estimates show residential areas to have an aggregate per capita energy consumption equivalent to 2 million MJ. On the other hand, it is important to note that each surface area is associated with energy of 100 GJ of energy.
Site Analysis
A site analysis reveals detailed information about prevailing weather conditions at the proposed construction site, which is a strongly influencing variable for the levels of energy consumption. Much detailed information about climate data specific to the proposed site shown in table 11 below.
Table 11 Summary of climate data
Month
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sept
Oct
Nov
Dec
Year
Record High Temperature
19
23
36
38
38
43
45
44
41
35
27
17
45
Average High temperature
7.9
11.9
19.8
24.4
30.4
36.6
3.93
37.9
33.7
27.3
17.6
10.3
24.7
Record low temperature
-20
-18
-1
1
8
14
18
17
10
4
-3
-9
-10
Average low temperature
-2.6
1
6.2
10.6
16.3
20.3
23
21.7
17.6
12.5
5.3
0
11
Medium temperature
2.6
6.4
13
17.5
23.3
28.4
31.1
29.8
25.6
19.9
5.1
17.8
Precipitation
23.4
23.9
24
27.9
11.4
3.7
1.4
0.7
1.8
4.4
19.4
19.7
161.7
Record high humidity
99
100
100
94
83
94
83
80
85
98
99
99
100
Average high humidity
81
81
64
66
55
46
43
44
50
56
71
86
62
Record low humidity
16
13
7
6
5
2
5
5
5
6
9
14
2
Average low humidity
44
39
23
22
16
11
11
11
13
18
30
42
23
IKIA Climate Area
Seasons
Winter
Spring
Summer
Fall
Year
Average sunshine hours
5543
771.6
988.1
6724
29855
Evaporation amount in mm
50.4
907.4
136
3509
2607.7
Average high speed wind
168
183
13
136
16.2
Average angel wind degree
298
303
268
268
293
Rahshahr International, 2011
The above table details the nature of the climatic conditions at the proposed site and the likely influence on carbon emissions. In addition to that, the climate allows for the implementation of strategies specifically tailored to mitigate and allow for appropriate carbon emission management at the site (Dunnett & Nolan, 2004).
On the other hand, the amount and rate of urbanization asociated with carbon burning activities contribute significantly to strategies formulated to manage carbon and other environmental pollutions.That includes construction projectsincludedin the development list around the IKIA corridor and the two North subways.
It is important to incoporate another access route into IKIA to help make the proposed region accessible, making the region expreince less congestion (Hogrefe, Lynn, Civerolo, Ku, Rosenthal, Rosenzweig, Goldberg, Gaffin, Knowlton& Kinney, 2004). Other issues to be considered during the contruction process activities related to carbon emissions when constructing access routes.
It is important to define an appropriate roads network particulalry with respect to the aspect of the wind, the mountains, and the rains as a strategy of reducing emissions into the emvironment (Asner, Scurlock,Hicke, 2003). At this point, it is important to examine in detail the carbon footprint for each of the carbon emitting activitiesthat consume energy in the following section.
Carbon Foot Print
From an investigation of energy intensiveand carbon producing activities, development needs and projections, significant amounts of energy will have to be burned and strategies have to be put in place to curb the final effects from the emissions. Typically, that also includes land use activities and the size of land in use besides proposed construction activities (Liu & Baskaran, 2003).
Typically, most of the land use is biast to the service industry which appears to be the largest single most carbon emitting source. Typically, the activities and the resulting effects due to the use of green roof systems are analysed and summarised in the following table (Che-Ani, Shahmohamadi, Sairi, Mohd-Nor, Zain & Surat, 2009) in table 12 below.
Table 12 Effects of different factors on Green roofs
Factor
Possible causes
Green roof systems effects
Temperature
Caused by island effects, smog, and lower wind speeds.
Reduced amount of smog, reduced island effects, enhanced cloud cover, controlled flow and clean wind.
Cloud cover
Wind
Project location
Effects due to Altitude
Effects are on wind flow characteristics, temperature, precipitations levels, fog effects, and many others.
Curbs rising temperatures and carbon absorption due to human and other energy consuming activities. One strategy is to use air conditioning within the city. Also influenced by the topography of the region, mountain ranges and buildings.
Topographical aspects
Source: Performance evaluation of an extensive green roof, 2005
Factor
Possible causes
Green Roof System effects
Population concentration of buildup areas
Surface area covered
Affects airflow, increasing both outdoor and indoor pollution levels
Height significantly hampers airflow increasing the concentration of pollution particles in the air.
Traps carbon and related chemicals by reducing the levels of carbon in the air as modeled elsewhere in the paper
Low heights allow low-level air absorptions leading to a reduction in air polluting substances.
Spacing between buildings
Height effects of buildings
Rahshahr International (2011)
Factor
Possible causes
Effects due to green Roof System
Site geometry
Horizontal airflow hampered due to high coefficient of friction of the road surfaces. The buildings and other structures influence radiation levels.
Reducingin island effect
Anthropogenic
Heat
Thermal effects due to industrial activities
Energy consumption from controlling internal and external building temperature
Reduces the aggregate effects due to temperature rise due to the albedo effect
Transportation energy
Due to population growth causing a rise in temperature
Carbon intake through the plant’s intake system
Energy consumption due to cooling effects
Energy consumption leading to carbon pollution
Carbon absorption
Air pollution
Rising temperatures and high carbon concentrations
Carbon and other emissions absorbed.
Land use effects
High carbon emissions and other pollutants
Appreciates available land for use particularly for planting vegetation
Wind Speed
Lower wind speed due to buildings, which increase concentration of pollutants due to emissions from air.
Uptake and intake of carbon and carbon related emissions reducing aggregate effects due to gaseous emissions.
Rahshahr International (2011)
It is important to consider a variety of plants known to thrive in the proposed facility. Typically, the plants respond well when planted in dry conditions. These are inherent characteristics of semi-arid and arid areas typical of the Tehran environment (Dunnett, Nagase, Booth& Grime, 2005). n addition to that, the plants demand low maintenance costs thus making the overall maintenance cost for green roof systems within reach of many residents in the proposed site (Köhler, 2003) and (Heinze, 1985) as illustrated in table 13 below tolerant plants drought
Table 13
D. forestry with use plants of tolerant to drought (low maintenance)
Common name
Botanic name
Common name
Botanic name
sweet sagewort, Burzeh
Artemisia fragrans
20
Hertia angustifolia
1
Calligonum
Calligonum bungei
21
Niger arabic
Stipagrostis plumosa
2
Calligonum
Calligonum polygonoides
22
jimsonweed
Datura spp.
3
Calligonum
Calligonum comosum
23
Pteropyrum aucheri
4
Mountain almond
Amygdalus scoparia
24
Caper bush
Capparis spinosa
5
Himalayan laburnum
Sophora hortensis
25
Ephedra, joint fir
Ephedra intermedia
6
Berberis
Berberis orientalis
26
Rosin-weed, Rudravanti
Cressa cretica
7
Salt Tree
Halimodendron halodendron
27
Smirnovia iranica
8
Almond
Amygdalus lycioides
28
Seidlitzia rosmarinus
9
Wolf berry
Lycium depressum
29
Artemisia
Artemisia sieberi
10
Chaste tree
Vitex agnus castus
30
Fortuynia racinii
11
Heliotrope, turnsole
Heliotropium aucheri
31
Nitre Bush
Nitraria schoberi
12
White sage
Atriplex canescens
32
Oriental fountain grass
Pennisetum orientallis
13
A variety of plants to incorporate into green roof system
Sage brush
Atriplex lentiformis
33
Russian Sage
Perovskia abrotanoides
14
Oriental worm wood
Artemisia scoparia
34
Mullein
Verbascum sp.
15
Bean caper
Zygophyllum eurypterum
35
Black saxaul
Haloxylon aphyllum
16
Locoweed
Astragalus squarrosus
36
Tamarisk
ramosissima Tamarix
17
Pistache
Pistacia Khinjuk
37
Kashgar Tree
Tamarix hispida
18
Prickly Russian thistle
Salsola spp.
38
Athel tamaisk
Tamari aphylia x
19
Source: Rahshahr International, 2011
Analysis and Discussion
According to this study, both intensive and extensive green roofs demonstrate several benefits. An examination of the entire area where the planned construction of an airport and surrounding areas have shown a great potential for the construction of green roofs on the buildings to be erected within that region. That typically borrows from the modern concept of benefits of green roofs and the associated technologies.
Thus, borrowing from historical application of green roofs, it has been in modern times that the concept of green roofs as a pollution control mechanism has been studied as one of the mainstream methods as an air pollution control technology.
From theoretical and practical perspectives, green roof systems are one of the most important strategies for reducing pollution effects on the environment particularly specific to the proposed airport construction site. Typical of the green roofing systems are intensive and extensive green roof systems. Both systems in theory and practice, when evaluated come with several benefits, reinforcing the rationale for their implementation as pollution mitigation techniques in urban areas.
Accruing benefits include water quality and environmental benefits such as storm water management, reduction of urban island effects, improved air quality, improved biodiversity, and positive effects on climate change, aesthetical revelations, and a CO2 emission control mechanism are other benefits associated with green roofs at IKIA.
In order to understand and model the benefits from green roof systems for any private and public investor at IKIA, it is important to conduct a mathematical analysis for various benefits as detailed below.
One of the benefits modeled mathematically is the water quality management. Water quality benefits arise from the capabilities of plant metabolic processes, evapo-transpiration mechanisms, and a number of microbial activities. In addition to that, green roof attenuation activities decrease the concentration of waste chemicals through chemical and physical processes (Lazzarin, Castellotti& Busato, 2005).
One method based on discussions from above is the unit water loading (UAL) that enables calculations on the amount of water loading in a specific unit area under consideration to be performed, based on a number of variables. The variables include EMCi for calculating concentrations when testing the quality of water at any given time during quality analysis and events (n) which provide a basis for the starting point of the calculation.
A is the catchment area which captures the entire IKIA area, and Vi denotes the amount of runoff precipitates that can be accumulated from the roofs. However, it may be difficult to quantify the amount of runoff water. However, the following mathematical expression estimates the amount of controlled water (Hall & Pfeiffer, 2000).
It is important to model the quality of water to determine the weighted mean, which is the volumetric concentration (MCVW) of water, and the variables that significantly influence the outcome of the calculations.
The above mathematical expression provides a clear way to calculate variables that constitute the quality of water under investigation at any point in IKIA. However, further research in the mathematical model need to be done to address every runoff event in the investigation and for a long period.
Another benefit is storm water management. Analytically, one can perform calculations on water management benefits based on different mathematical expression explained elsewhere in the paper.
On the other hand, the aggregate values of the accruing benefits, the monetary cost of storm water management and the value of erosion mitigation of the green roof system during the construction process are strong benefits. On the other hand, the water retention capacity of the green roof system within the area of the green roof under considerations indicates the viability of using the green roofs to capture and retain runoff water.
Based on the above mathematical model, any public or private investor can calculate storm water benefits in monetary terms. As a pollution control mechanism, carbon sequestration values due to CO2emissions, insulation of heat loss into the environment thus resulting in a reduction of energy demands for a building, evapo-transpiration effects, and an aggregate reduction of the urban heat island effect.
On the other hand, the ecological foot print lays further support to the need for the use of green roof systems as illustrated in the following where the service sector in Iran is estimated to consume energy estimated between 1.43 M.J and 107 552 milliards MJ. That is in particular within the IKIA region.
On the other hand, per capita consumption specific to areas susceptible to flooding is 230906 MJ, which contributes energy estimated at 30.787 MJ in the areas of crop production, among other agricultural activities. In addition to that, estimates of per capital consumption of energy are in the range of 143 million GJ equivalents of 1.43 hectares.
Thus, the amount of carbon generated from these activities is bound to generate significant amounts of CO2and water into the environment calling for significant actions to formulate methods and in particular the use of green roofs as mitigation techniques. On the other hand, it is evident from the above study that significant emissions of carbon into the environment is bound to cause smog and other forms of environmental pollution that require specific technologies to clean up.
Conclusion
The main aim of the study is to conduct an investigation into green roofs as a method to mitigate air pollution with special reference to Tehran, Iran. Green roofs have been in existence since the time of antiquity. This study has focused on available literature and information on green roofs constructed in urban areas with limited space.
The space limit does not allow for the construction of large gardens on conventional roofs, reinforcing the need to make use of minimal space on conventional roofs. Thus, the study is an investigation on green roofs to mitigate air pollution with special reference to Tehran, Iran.
The paper examines many of the factors that influence carbon-generating activities. These factors include the topology of the area, the direction of the wind, the location of the site, the source of electrical power, industrial centers, residential areas, usable areas, and zoning for flight routes.
These carbon generating activities and the use of appropriate green roofs as a carbon control method in the area proposed for the construction of the IKIA airport and the need to construct green roof systems as a carbon management strategy and a pollution mitigation mechanism.
Green roofs have come with several benefits both to the user and to the environment. These include:
The green roof provides thermal insulation, a benefit consequently leading to energy conservation and CO2 reductions into the environment.
Plants grown on green roofs provide a mechanism for reducing CO2 emissions into the environment, thus mitigating carbon pollution into the environment.
Green roofs reduce urban island effects through a carbon absorption mechanism.
Green roofs have the capacity to mitigate the effects of storm water by reducing the rate of absorption of rainwater into the underlying surface.
Green roofs have the effect of fulfilling the aesthetical desires of people, thus acting as a tourist attraction.
Extensive green roofs have the capability to remove dirt particles from the air resulting in cleaner air.
Green roofs have a biodiversity benefit compared with brown roofs, making the roofs beneficial as a tourist attraction.
Typically, green roofs fulfilled aesthetical feelings of the highly regarded in the societies in the past. However, due to current pollution and other environmental challenges facing governments and individuals, green roofs are among the most critically important strategies for mitigating the effects of air pollution due to energy consumption and carbon emitting activities.
Green roofs fall into intensive and extensive roof systems and each system has specific benefits that distinguish each. Thus, the rationale to construct a green roof is due to several benefits among them being a pollution control mechanism. In addition to that, other benefits include storm water management and mitigation of urban island effects.
In addition to that, it is possible to tailor a green roof to fulfill aesthetical views that may lead to tourist attractions. That is the case with IKIA, a region proposed for the construction of an airport facility. A case study analysis of Tehran serves to inform the study at IKIA. Typically, the site proposed for the construction of the airport facility situated some kilometers from Tehran experiences semi-desert and desert climatic condition.
In addition to that, high-rise buildings are proposed for construction in the region typically due to job opportunities to accommodate rising population. Energy consuming activities that lead to the production of carbon and related compounds are bound to rise significantly, contributing to rising levels of pollution.
As a critical approach to overcome all the challenges associated with a myriad of CO2 generation activities, it is the construction of green roofs as a pollution control mechanism that form one of the methods of addressing the pollution control problem. However, there is need to conduct further research to mathematically model the benefits from green roof.
It is, however recommended that detailed studies be done at the proposed region for the construction of the airport facility. Further, there is need conduct a detailed analysis of available documents detailing the topology of the region and other geographical details in other studies.
On the other hand, established facts show that the wind direction strongly influences the flow and direction of the movement of dirt and smog particles in the air. These movements have detrimental effects on the temperature of the environment within the IKIA region, where the proposed site for the construction of the airport is to occur.
The direction and speed of wind is therefore an important element to consider when setting up a city. Typical of the area under consideration is the wind speed and direction. Facts show that the entire area experiences wind flow of 23 knot (11.5 m/s) to the west, further urging the movement of smog and other dirt particles into the region, eventually increasing the effects of the resulting particles on the environment.
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Pollution entails the introduction of substances into the environment in quantities that can change environmental conditions and in turn, harm organisms. Acid rain and ozone pollution are a form of pollution, which entails the release of gaseous and dust particles in quantities that destroy the integrity of the atmosphere and affect organisms in their respective habitats and ecosystems.
Essentially, the atmosphere is an integral natural resource of the earth because it contains and maintains gases in appropriate proportions, which are essential for the survival of organisms in nature. In this case, the occurrence of acid rain and ozone pollution is due to the emission of gases in huge quantities, which have the capacity to pollute the air. Singh and Agrawal state that human activities such as the burning of fossil fuels and natural causes such as volcanic eruptions release nitrogen oxides, sulfur dioxides, and ozone, which are precursors of acid rain (15).
These oxides combine with atmospheric water and form acid rain. Aggarwal et al. state that the interaction of nitrogen oxides and volatile organic compounds contributes to the formation of terrestrial ozone, which is a pollutant responsible for global warming (1991). In this view, to enhance understanding of air pollution, the research paper examines the nature of acid rain and ozone pollution and subsequently discusses its causes and effects.
The Nature of Acid Rain and Ozone Pollution
Acid rain is a form of pollution characterized by the presence of nitric acid and sulfuric acid in the rain, snow, hailstones, dew, and fog. The presence of nitrogen oxides (NOx) and sulfur dioxide (SO2) in the atmosphere leads to the formation of acid rain. According to National Atmospheric Deposition Program, carbon dioxide, oxygen, sunlight, ozone, and water catalyze the conversion of nitrogen oxides and sulfur dioxide into nitric acid and sulfuric acid, respectively (par. 2).
These acids then accumulate in the atmosphere and fall to the earth’s surface as rain, snow, dew, fog, and hailstones. The amount of nitric acid and sulfuric acid is proportional to the number of nitrogen oxides and sulfur dioxide that are present in the atmosphere (Singh and Agrawal 15). Hence, acid rain occurs when there are high proportions of nitrogen oxides and sulfur dioxide in the atmosphere.
Ozone pollution is a form of air pollution, which occurs when the amount of ozone (O3) increases in the atmosphere. Although ozone that is present in the stratospheric layer is important because it protects humans and organisms against harmful ultra-violet radiation, its presence in the tropospheric layer is harmful. Aggarwal et al. argue that the presence of ozone in the tropospheric layer constitutes pollution because it acts as particulate matter that scatters sunlight, promotes absorption of ultra-violet radiation, and causes global warming (1990). Hence, terrestrial ozone is a very harmful pollutant to humanity and organisms.
Causes of Acid Rain and Ozone Pollution
Human activities and natural processes are the cause of acid rain. The human activities that emit nitrogen oxides and sulfur dioxide are exhaust fumes from motor vehicles, industrial emissions from smelters and fossil fuels, and power stations that use fossil fuels (Singh and Agrawal 15). Given that exhaust fumes from motor vehicles and industrial emissions are common in urban centers, the emissions of nitrogen oxides and sulfur dioxides are very high.
National Atmospheric Deposition Program states that urban centers with high population density, automobile traffic, and industrial activities experience high levels of nitrogen oxides and sulfur dioxide emissions (par. 9). Natural sources of nitrogen oxides and sulfur dioxide are lightenings, oceans, and volcanic eruptions (Singh and Agrawal 15). However, these natural sources do not contribute significantly to acid rain.
An increased amount of terrestrial ozone occurs due to human activities, which release nitrogen oxides and hydrocarbons into the atmosphere. According to Aggarwal et al., motor vehicles, industries, and power plants burn fossil fuels and emit nitrogen oxides and hydrocarbons, which interact in the presence of ultra-violet radiation and lead to the formation of ozone (1990). The number of ozone peaks late in the afternoon after the emitted gases have absorbed enough heat to catalyze the formation of ozone.
Effects of Acid Rain and Ozone Pollution
Acid rain and ozone pollution have harmful effects on organisms because they have scorching effects on the leaves of plants. Given that acids have scorching effects, they destroy the integrity of the leaves and interfere with their functions. National Atmospheric Deposition Program states that acid damages leave and make them susceptible to environmental stresses and diseases (p. 12).
Singh and Agrawal also indicate that ozone damages leave by causing desiccation and changing coloration (1992). The damaged leaves lose their physiological functions of photosynthesis and cause plants to experience retardation in their growth and development. The ability to regulate the loss of water is lost; hence, predisposing plants to physiological drought. Moreover, the scorching effects of acids destroy the protective membranes of plants and make them susceptible to diseases.
Since organisms in the environment live within a narrow range of pH, acid rain causes a significant drop in the normal pH. Singh and Agrawal explain that acid rain causes acidification of water bodies and results in massive deaths of aquatic organisms such as fishes, amphibians, planktons, and microorganisms (18).
A slight change in aquatic pH has deleterious effects on organisms because it affects their biochemical and physiological processes. A normal aquatic environment has a pH of 6.5 or more, but a few organisms can survive at a pH of 5; however, none can survive on a pH of less than 5 (National Atmospheric Deposition Program par. 15). Therefore, acid rain has the potential to kill all aquatic organisms if it occurs on a large scale.
Acid rain also has a considerable impact on agriculture because it affects the availability of nutrients in the soil. National Atmospheric Deposition Program reports that acid rain lowers agricultural production by reducing soil nutrients, changing the proportion of chemicals in the soil, and killing important microbes in the soil (par. 16). Acid rain reduces soil nutrients because it dissolves and leaches them away. Singh and Agrawal’s state explain that acid rain reduces the pH of the soil and causes the liberation of cations such as potassium, magnesium, and calcium, which are important in the growth and development of plants (18).
When leaching occurs, the proportion of nutrients in the soil reduces, while the proportion of toxic heavy metal increases. A decrease in pH harms microbes in the soil, hence, reducing the rate at which important microbial processes occur in the soil. Ozone is a greenhouse house gas, which has the capacity to cause global warming and affect the distribution of rainfall patterns in various places globally. Aggarwal et al. assert that the increased concentration of terrestrial ozone contributes to global warming because it has a greenhouse effect.
Acid rain has harmful effects on humanity because it dissolves heavy metals and causes respiratory diseases. National Atmospheric Deposition Program states that acid rain pollutes water by dissolving lead and copper, which are harmful metals, and inhalation of acidic fog causes respiratory illnesses such as asthma (par. 19). Exposure to lead and copper causes mental and systemic illnesses. The elderly are prone to respiratory diseases owing to their aging respiratory system.
Despite the fact that ozone in the stratosphere is protective against ultra-violet radiation from the sun, its presence in the troposphere is harmful to humanity and organisms. Ozone pollution has harmful effects on humanity because long-term exposure increases the occurrence of asthma, skin diseases, and lung cancer among individuals (“Green Facts: Air Pollution” par. 3). Aggarwal et al. argue that the combined effect of ozone and carbon monoxide causes acid rain and subsequently contributes to the damage of lung tissue (1990). In this view, acid rain and ozone pollution are responsible for the increasing cases of lung cancer and asthma.
Given that acid has corroding effects, acid rain corrodes human structures. National Atmospheric Deposition Program reports that buildings, statues, monuments, vehicles, metallic structures, and tombstones corrode faster in acid rain than in normal rain (par. 21). In this case, acid rain hastens deterioration of human structures, and thus, reduces their longevity.
Conclusion
Acid rain and ozone pollution are the dominant forms of air pollution because they emanate from human activities. Emissions of nitrogen oxides and sulfur dioxide do not only lead to the formation of acid rain but also act as catalysts in the formation of ozone.
The combined effect of acid rain and ozone leads to the destruction of terrestrial plants, death of aquatic organisms, reduced agricultural production, the emergence of human diseases such as lung cancer, asthma, and skin diseases, and deterioration of human structures. Therefore, acid rain and ozone pollution are public and environmental health issues that require effective mitigation measures.
Works Cited
Aggarwal, Anjali, Reeta Kumari, Neeti Mehla, Rishi Singh, Sonal Bhatnagar, Kameshwar Sharma, Kuldeep Sharma, Amit Vashishtha, and Brijesh Rathi. “Depletion of the ozone layer and its consequences: A review.” American Journal of Plant Sciences 4.10 (2013): 1990-1997. Print.
Singh, Anita, and Madhoolika Agrawal. “Acid rain and its ecological consequences.” Journal of Environmental Biology 29.1(2008): 15-24. Print.
National Atmospheric Deposition Program. Acid Rain. 2014. Web.
Groundwater exists naturally in the usable or extractable from beneath the earth’s surface. It occupies soil pore spaces and the fractures of rock formations underground that can connect to other underground water bodies like aquifers.
Amount of water
The groundwater in UAE meets the needs of 51% of users in terms of quantity mainly for irrigation. As the main natural resources, its distribution is scarce in the southern and northern parts of the country. The estimated volume of groundwater is 640 BCM, which is very large. Unfortunately, only 20 BCM of the available water is considered fresh. Based on current demand, the UAE total annual water demand will double from 4.4 BCM in 2008 to 8.8 BCM in 2030. Demand for water will mainly be in urban areas. These uses include industrial, commercial, public facilities, and institutions. The current demand for forestry or agriculture will decrease in the same period or shift to other sources of water other than groundwater (Al Mulla 2011).
Overall quality
Groundwater existed as the main source of water for all users in the country until rapid demand forced authorities to develop alternative sources of water. Also, the rapid expansion of development and urbanization are factors to look out for when evaluating water quality. The two factors have led to the over-abstraction of groundwater to meet the larger needs for agriculture. This has resulted in a sharp drop in water levels in the fresh groundwater region. Moreover, there is a constant salt-water intrusion from the sea.
This mainly happens in the coastal regions of the UAE. It arises from the lateral movement of saline water. The close sabkha-dominated areas are a source of the intrusion. Moreover, the upwelling of salty water from low stratigraphic units is another major source of the intrusion. The low-quality water enters the shallow aquifers that are sources of groundwater. On the other hand, increased agricultural production has meant an increase in chemical fertilizers that have caused a rise in nitrate concentrations in some areas where groundwater is available.
Renewability
Much of the UAE experiences high temperatures that reach over 40 degrees centigrade in summer. The rate of evaporation is very high at about 8.2mm and the annual mean rainfall is about 120 mm. These factors affect the potential of near-surface groundwater to exist and renew based on the rate of extraction for consumption. The main recharge for groundwater is rainfall, which goes off as runoff and sips into the group to recover the groundwater amounts. The total renewable freshwater resource for the UAE is estimated as less than 150 MCM/Year and this includes the groundwater sources as well as the surface water sources.
On the other hand, demand for water has been increasing with the largest consumers being forestry and agriculture as users of groundwater while amenity and domestic mostly used other sources of water. The flashfloods dams constructed around the UAE to collect surface water are also major sources of groundwater recharge. Climate change is also increasing the vulnerability of water scarcity in the UAE. The effect can be reduced when water demand management changes to be more efficient (Al Mulla 2011).
Groundwater protection
The protection of groundwater starts with the assessment of the quality of water available and determining the major risks facing the supply of fresh groundwater. Groundwater bodies can then be classified as good or poor based on their quality and size before measures are taken to protect the water. The abstraction of groundwater is the main cause of pollution as it causes saline intrusion. The salinity is increased in a given area when there is the use of water for irrigation. Most irrigated lands are waterlogged and saline and the surface waters get underground to pollute fresh sources.
Therefore, the first and most significant action against the destruction of groundwater sources is to have limits on ground flooding with saline irrigation water. In this case, the area may have to place a ban on irrigation types to prevent such flooding that is an inefficient way of using water and is a major risk of salinizing the available groundwater. In the case of the UAE, the biggest threat is encroachment by seawater. Some aquifers may also have a very slow flow rate and when they do not receive enough recharge of freshwater, they deteriorate in their water quality. Another source of water deterioration would be from mining activities that have mine drainage and tip leaching. For the UAE, mining causes can be the infiltration of discard oilfield brines.
There is a relation between surface water and groundwater. Surface water is the source of groundwater and plays a major role in groundwater renewal. Surface water sips into the soil and rocks beneath it to become groundwater. On the other hand, groundwater reappears as surface water what there is a sudden change in altitude to create springs and surface water bodies.
Water pollutant
According to Demirak et al. (2006), heavy metals come from a variety of natural and anthropogenic sources. The combustion of coal is one of the most important sources of anthropogenic emission of trace elements including several metals. The metals then distribute in sediments adjacent to the settlement areas. The heavy metal pollution can be manmade due to the establishment of coal-burning plants and it can also be natural in areas of fluvial conditions, metal pollution happens due to direct atmospheric deposition.
Heavy metals pollute water to make it unsuitable for human consumption and animal consumption. The study by Demirak et al (2006) showed that the presence of a coal power plant known to be a major source of heavy metal deposits in soil sediments. However, this is not a guarantee that downstream water will be polluted to the extent that maximum safety levels of the water are detected upon testing. However, there is a need for caution as pollution through heavy metals is accumulative.
Heavy metal water pollution in many parts of the world arises from industrial waste coming from mining, metallurgy, foundries and similar industries. When human and animal bodies absorb heavy metals they experience severe damage in their vital organs and can lead to failure of the organs. There are ions of heavy metals in consumable water piped or transports many miles from the incident of pollution. Therefore, heavy metal water pollution is a threat to many more people and environments other than the locality adjacent to the main source of pollution (Vila et al. 2011).
The pyrite mine-reservoir accident in Aznalcóllar, Spain in 1998 was a national environmental catastrophe that highlighted the potential scale of heavy metal hazards to the environment. After the incident, there were massive clean-up initiatives that include mechanical removal of toxic sludge and surface soil. The accident jeopardized the quality of groundwater in the area and adjacent areas that rely on Aznalcóllar for the replenishment of the ground or surface water supply. The accident was constrained by the application of soil amendments aimed at preventing the dispersion of the contaminants.
Nevertheless, the area remained contaminated. Also, the activities of cleaning up that included the removal of sludge ended up burying more sludge. The pollution damage than occurred when the aerobically enhanced pyrite oxidation in the sludge-contaminated soil reacted with the metallic and metalloid elements present through the acidification process to result in increased risks of contamination (Vázquez et al. 2011). After the reactions, much of the soil and sludge were contaminated and it had become very acidic.
While in the soil, the heavy metal elements are influenced by factors such as soil pH, the presence of organic matter, the redox potential of the soil and the temperature. When there are favorable conditions, physical, chemical and biological processes act without intervention of humans to reduce mass, toxicity, and mobility or the volume and concentration of contaminants like heavy metals from groundwater and the soil. In the case of the Aznalcóllar soil contamination incident, there have been limited studies to evaluate the effect of years of attenuation and confirm whether the groundwater was still susceptible to pollution.
After the accident, seasonal rainfalls on the soil affected soil pyrite oxidation and caused a significant decrease in soil pH after it had initially increased due to the accident. The rains also caused leaching of salts especially in the period from the year 2003 to 2006. Another feature that contributed to reduced toxicity was the accelerated growth of wild plants and weed growth. The reclamation of the land through the natural process was fast because the initial topsoil had been mechanically removed together with the sludge. However, there was the continued release of Fe oxides from pyrite due to oxidation and succeeding perspiration.
The area also experienced a vertical distribution of elements across the soil profile leading to increased soil acidity and increased risk of groundwater contamination in the adjacent areas. Overall, most water pollution risks of heavy metals come from manmade activities or accidents like the mine disaster in Spain in 1998. The damage starts with the soil which then affects surface waters when there are runoffs or groundwater after subsequent perspiration activity.
Water quality
Water quality associates with the balance of chemical, biological, physical, and radiological characteristics of water when analyzed. Water from different sources has different quality attributes that can be analyzed by looking at the color, conductivity, dissolved oxygen, electrical conductivity, pH, hardness, salinity, suspended sediment and turbidity. The remark on water quality and suitability will also depend on the intended usage of the water.
Water-related diseases are diseases that arise when there are water problems such as contamination or shortage. On the other hand, waterborne diseases are a type of water-related diseases arising when the transmission of the disease occurs through drinking contaminated water. The contamination is by pathogens that are transmitted from excreta to water through human activity (Gleick & Cain 2004). Waterborne diseases include most diarrheal disease that is caused by viruses, parasites and bacteria, and typhoid. Thirty other parasites that are known to affect the human intensities upon taking such water are also contaminants. Other forms of water-related diseases include water-washed diseases and water-based diseases.
The illnesses occur when there is limited water that could be used to wash and sustain personal hygiene. Thus, individuals become infected with diseases. The water-based diseases occur when hosts whose habitat is water or whose survival need is water pass on diseases to humans. They can be ingested or they can be exposed to the skin. Upon doing so, they cause diseases in humans. Examples of illnesses arising in this manner are schistosomiasis and dracunculiasis, which are quite deadly going by the fact that they have victimized more than 200 million people globally (Gleick & Cain 2004).
When living in a rural community where water safety is a priority, the first thing will be to check that there is no contamination of the current supply of drinking water. Dams and other water sources would be fenced off to avoid human activity that can introduce contamination. There will be filtering and boiling of water before drinking as a way of killing all organisms that might be responsible for causing infections. There will also be sensitization programs for the residents of the rural area about maintain their hygiene as individuals. The campaigns will continue to their work or home to reduce the chances of contamination and the spread of water-related diseases.
Wastewater treatment
Sludge comes as a byproduct of water treatment and it can be on-site or off-site. The sludge contains solids. They would have been removed from the water during treatment. Thus, the sludge is often organic due to soluble organic substances. They convert to bacterial cells after extraction from water. Sludge varies widely in its characteristics because it comes from many sources. It can be from fresh fecal material. This would have been collected from bucket latrines. After that, the sludge can undergo bacterial decomposition for more than a year in a pit latrine. Overall, sludge from different sources will have pathogens that can cause diseases. Therefore, it should be handled with care. In addition to pathogens, sludge may contain heavy metals and other deadly pollutants that risk being reintroduced to water meant for human and animal use.
The level of treatment needed for sludge before releasing it to the environment differs according to the potential contamination contained within it. Fecal sludge is rich in nutrients. The main ones are nitrogen and phosphorus. Therefore, it has potential nutritional benefits to plants when used as fertilizer. Such sludge also has carbon that stabilizes and becomes a soil conditioner, which advances soil texture and provides a proper structure for roots. Treatment of sludge starts with stabilization from a point of high biochemical oxygen demand. The stabilization reduces this demand. Sludge can be stabilized aerobically. This would happen in aeration tanks similar to an activated sludge procedure. In the process, thickening and dewatering happen to gain enough solids content and convert sludge into usable organic matter. Sawdust may also be used. Also, the sludge can be processed through composting or aerobic digestion to make methane and carbon dioxide gas as biogas.
Composting can be simple. It may include the use of windows, which help in providing oxygen to the bacteria responsible for decomposition. As a result, the overall rate of decomposition increases. Therefore, heat insulation during the process is also necessary. After composting, the sludge is ready for use as organic fertilizer or buried (UNEP 2015).
Water sustainability indicators
Sustainability aims to use resources in a way that does not deplete their sources and water sustainability seeks to achieve the same through careful management of water sources and improvement of processes that lead to the regeneration of water supply. Water sustainability indices are used to evaluate the extent of sustainability of practices used in managing water. The water sustainability definition comes from the existing definitions of sustainable development principles that various institutions such as the United Nations have proposed. Water is considered a resource and its sustainability are achieved by having water resource systems designed and management do fully contribute to the objectives of the society. The condition has to be relevant now and in the future while the integrity of ecological, environmental and hydrological properties is maintained.
Indicators are measures of facts or conditions that can be qualitative or quantitative. Regular observation of indicators can provide data for analysis for a particular period. When indicators are grouped, they result in a component. Also, indicators can have sub-indicators. When several indicators are put together, they make up an index or composite indicator. Water sustainability indicators are selected based on their sensitivity to change in time, change across space and their predictive or anticipatory nature. They have to be unbiased, integrative, offer appropriate data transformation and have reference or threshold values available. Formulas for water sustainability vary but use key methods such as categorical scaling and continuous re-scaling. They can also use distance to a reference (Juwana, Muttil & Perera 2012). Indicators are assigned weights that will be used to develop the index and determine water sustainability as a measure of its replenishment risk over time.
Reference List
Al Mulla, MM 2011, UAE state of the water report 2nd Arab Water Forum, Web.
Demirak, A, Yilmaz, F, Tuna, AL & Ozdemir, N 2006, ‘Heavy metals in water, sediment and tissues of Leuciscus cephalus from a stream in southwestern Turkey’, Chemosphere, pp. 1451-1458.
Gleick, PH & Cain, NL 2004, The world’s water 2004-2005: The biennial report on freshwater resources, Island Press, Washington, DC.
Juwana, I, Muttil, N & Perera, BJC 2012, ‘Indicator-based water sustainability assessment — A review’, Science of the Total Environment, vol 438, pp. 357-371.
UNEP 2015, Sludge treatment, reuse and disposal, Web.
Vázquez, S, Hevia, A, Moreno, E, Esteban, E, Peñalosa, JM & Carpena, RO 2011, ‘Natural attenuation of residual heavy metal contamination in soils affected by the Aznalcóllar mine spill, SW Spain’, Journal of Environmental Management, vol 92, no. 8, pp. 2069-2075.
Vila, M, Sánchez-Salcedo, S, Cicuéndez, M, Izquierdo-Barba, I & Vallet-Regí, M 2011, ‘Novel biopolymer-coated hydroxyapatite foams for removing heavy-metals from polluted water’, Journal of Hazardous Materials, vol 192, no. 1, pp. 71-77.
Plastics are made from chemicals extracted from dirty, non-renewable natural resources. Such resources include fossil oils, naturally occurring gases, and coal (Thompson, 2018). Plastics are considered organic rather than inorganic because of their chemical properties. A molecule is categorized as organic if it has hydrogen and carbon atoms in its structure with carbon atoms being its main building blocks. Organic molecules are large and have a complex structure when compared to inorganic ones. On the other hand, inorganic molecules have a simple structure and usually lack carbon atoms. Chemically, plastic molecules are made of numerous elements such as nitrogen and oxygen, including hydrogen and carbon atoms, which form the main part of their structure.
The materials from which humans extract carbon occur naturally and form part of the lithosphere. Coal is an example of these materials and is formed from flora and fauna remains that were part of the biosphere. After use and disposal, carbon ends up in the lithosphere and hydrosphere in solid form (Thompson, 2018). The solids degenerate into small particles, some of which are absorbed in the biosphere through ingestion by living organisms.
Carbon-rich molecules are used to generate the energy required in the manufacture of carbon. After the process, the carbon in these energy sources ends up in different spheres including the atmosphere, hydrosphere, and the biosphere. Combustion of carbon-rich molecules results in gaseous and liquid byproducts. Gases such as carbon dioxide are released into the atmosphere from where they are absorbed into the biosphere. Water in vapor form is also a product of combusted carbon-rich molecules and forms part of the hydrosphere from where it is absorbed into the biosphere.
Plastic Pollution Consequences
Plastic pollution has various potential environmental consequences, with micro-plastic invasion, especially its impact on humans and animals, being of great concern. Micro-plastic invasion describes the appearance of minute plastics, also referred to as micro-plastics in the environment. Microplastics include all tiny plastic particles whose size range from 5mm to microscopic. Some of these particles are factory manufactured while others result from the degrading big plastic products such as bottles and bags.
Inefficient disposal methods of plastic wastes are the main causes of micro-plastic pollution. There are about 15 trillion tons of micro-plastics in the oceans, with an equivalent amount in the lakes and soils worldwide (UNEP, 2018). Animals such as fish have ingested these tiny plastic particles, with the microscopic ones being absorbed by plants such as planktons. The absorption of micro-plastics by plants is alarming as they are the basis of food chains.
The study by Browne in 2008 that proved the presence of microplastics in a mussel’s bloodstream demonstrates the ecological implications of micro-plastic invasion (Thompson, 2018). Traces of micro-plastics have also been found in drinking water and the air (UNEP, 2018). In addition, micro-plastics can be absorbed from plastic utensils and cosmetics (Thompson, 2018). Humans and other animals are at risk of harm by these particles. Scholars claim that exposure to these particles affects the reproduction, growth, and immunity of organisms and their subsequent generations (Thompson, 2018).
The largest use of plastic
My largest use of plastics today is of facemasks when protecting myself from the spreading COVID-19. I have been using single-use facemasks daily since the declaration of the virus as a pandemic. Research about these facemasks has indicated that they are made from plastics derived from fossil fuels (Chan, 2020). It has pointed out the alarming increase of deposits of single-use facemasks in water bodies such as rivers and the sea. Researchers estimate that countries like the United Kingdom would generate 66,000 tons of waste in a year from single-use masks (Chan, 2020). Such findings are of great concern to me as they suggest my contribution to the increased plastic pollution. For this reason, I plan to start using reusable masks and those made of cloth. I also intend to encourage my friends to embrace this strategy to reduce the generation of plastic waste and pollution to the environment.
References
Chan, E. (2020). Disposable face masks and gloves are a plastics nightmare—but what’s the solution? Web.
Thompson, A. (2018). From fish to humans, a microplastic invasion may be taking a toll. Scientific American. Web.
UNEP. (2018). Our planet is drowning in plastic pollution. This world environment day, it’s time for a change. Unep.org. Web.
