Category: Acid Rain

The term “acid rain” was first used by Robert Angus in 1872. “Literally it means the presence of excessive acids in rain waters.” Acid rain is in-fact cocktail of mainly H2SO4 and HNO3, where the ratio of these two may vary depending upon the relative quantities of oxides of sulphur and nitrogen emitted.

H2SO4 is the major contributor (60-70%) to acid precipitation, HNO3 ranks second (30-40%) and HCl third. Acid rain is in fact a natural phenomenon occurring during any thunderstorm accompanied by heavy lightening or by volcanic eruptions.

However, it is the pollution of the air with nitrogen and sulphur containing gases, emitted by the industry, power station, planes and automobiles that produce acid rain which has alarmed many people because of the increasing potential hazard for environmental degradation including soil and water.

Acidification of environment is a man-made phenomenon. There is now no doubt that most acids come from human activities from cars, homes, factories, and power stations etc. there has always been some acid in rain, coming from volcanoes, swamps and plankton in the oceans, but scientists know that it has increased very sharply over the past 200 years.

The acidity is mainly associated with the transport and subsequent deposition of oxides of sulphur, nitrogen and their oxidative are produced by combustion of fossil fuels, smelters, power plants, automobile exhausts and domestic fires etc.

The accumulation of these oxides was first reported to be responsible for increasing an acidity in Swedish lakes and Rivers. The acid rain problem has drastically increased due to industrialization. Burning of fossil fuels for power generations contributes to 60-70% of total SO2 emitted globally. Emission of NOx from anthrogenic sources ranges between 20- 90 million tonnes annually over the globe.

The super stack and the mammoth smelters at Sudbury (Ontario) release about 2500 tonnes of SO2 into the air daily. It is the largest stack in the world and serves as a symbol of acid rain problems in North America. Incredibly, this one stack gives of 1% of the total SO2 released worldwide.

Many super stacks constructed recently facilitate long transport of gases and particulate, thus contribut­ing to the wide-spread acid deposition problem facing the United States and Canada today. Highly industrialized areas of the UK, Central Europe, Finland, Norway, Austria, and Switzerland were the net importers of sulphur compounds which contribute much for increasing acidity.

Acid rain is the environmental issue that can occurs negative impact towards human, animals, surrounding or even non-living things like property. The clean rain has a pH value between 5.0 and 5.5. Nevertheless, the pH of rain can become more acidic up to 4.0 if the rain combines with sulfur dioxides or nitrogen dioxides which those are from the industrial area. Some parties in industry are not taking serious on how they manage their company, thus the air and water pollution happened. Those pollutions in industrial area might be affecting the other area and the possibility the acid rain happened is high. Aftermath of acid rain, the surrounding will damage including buildings, plants and also human health. To overcome this issue, there are two solutions in engineering perspective which is by developing monitoring and sensing tools of the dangerous gases. This approach able to enhance air that strong acidic pollutants tracking systems. Next, semiconducting metal oxide based sensors for selective gas pollutant detection. In these both solutions, the sensors and internet of things (IoT) is what will be taking into account.

Acid Rain in China

Republic of China is a developed country which 40.5% of their gross domestic product are from industrial activities like manufacturing and construction in 2017. The industry of China is including iron, steel, aluminum, chemical, electronics and other. Thus, it makes China has made average PM2.5 which is harmful for people health because PM2.5 are small particles in the air that cause the air appear hazy and reduce visibility when levels are high. In 1970s, acid rain happened in China. The acid rain causes respiratory diseases worst due to Strong acidic gases such as CO2, SO2, and NO2. The respiratory disease like asthma or chronic bronchitis that make people hard to breath. Not only affecting people, China’s river also had the same experience which is Yangtze River where the acid rain mainly spread there. The most parts of Jiangxi Province, Fujian Province, Hunan Province, and Chongqing Municipality, as well as Yangtze River delta, Pearl River delta, and southeast Sichuan Province are the acid decomposition area. The total area that experience the unhealthy acid rain was around 10.6% of the national territory.

Fossil fuel combustion formed acid deposition and emitted freely to the atmosphere. The factor of forming that acid deposition is caused by coal and oil fired power plants and transportation such as road vehicle or ships. In late 1970s, China suffered acid rain and acidification of the environment. The biggest factor of acid rain in China is the extensive use of coal, thus sulfur dioxide released rapidly since 1970s. In few years after, the emission of SO2 is decreasing and the rate is faster than before. That situation is not healthy because SO2 is acidic. Oil is also a biggest source of sulfur in surrounding. The national average content of sulfur in the coal is 1.1%, but in some heavily industrial areas in the southwest China, the sulfur content can be as high as 4%. In fact, the total emission of sulfur in China’s atmosphere were -22 million metric tons’ in 2003. That were even higher than European emission. The number of transportation has increase dramatically from 6.2 million in 1990 to 36.0 million in 2003 and caused the emission of NOx estimated at 12 million t, which is more than half of total US emissions and European.

Engineering Sollution

As stated before, the strong acidic gases are CO2, SO2, and NO2 that causes pollutants and threatening human health and surrounding. Therefore, to overcome this problem, new tools develops to monitor and sense those gases quickly. In sensing the acidic air pollutants using single channel, it is difficult to detect the gas because they have similar chemistry in acidic molecules. Thus, the rational design of aminopolymer for selective different of acidic air pollutants is introduced. Traditionally, infrared (IR) sensor and solid-state sensor have been use to track and monitor air pollutant. Mobile interaction between analytes-column and number of IR absorption peaks of the analytes, gas chromatography and IR sensor can selectively detect strong acidic pollutants based on different strengths.

That detection tools are quite expensive, huge and complex, thus it would be difficult for the future generation to extend this pollutant detecting gas pollutant systems technology. The solid-state gas sensor technologies are based on electronics and Internet of Things (IoT) which it is a user-oriented ambient pollution tracker. It is also low-power consumption, miniaturization, device compatibility, multi-channel operation and integrated circuit (IC). Since the acidic air pollutants are similar chemical properties and very hard to differentiate the gas molecules, it is also difficult to use single channel material or single chip fabrication process. The solid-state gas is sensing the signal based on the variations of electrical properties with using multi-channel material.

Moreover, the developing of semiconductor metal oxide based sensors for selective gas pollutant detection is also donated in improving this detecting gas pollutant system technologies. The semiconducting metal oxide (SMO) is a sensor that widely used in chemiresistive gas sensor which it undergoes reduction and oxidation to react the same class of gases. The operation of gases by SMO sensor is by exchanging electrons with target gas at certain characteristic rate and affecting the sensor’s resistance and yielding a certain signal. SMO is applying the sensor as catalysts and electric conductive detectors toward multiple gases. There is some advantage on using SMO which is low cost, small size, measurement simplicity, durability, ease of fabrication and low detection limits or ppm level. It also tends to long-lived and resistant to poisoning and nowadays, it is widely use as gas sensor detection.

Various parameters that affect the function of the solid state gas sensor, such adsorption ability, electro physical and chemical properties, catalytic activity, thermodynamic stability and the adsorption/desorption properties of the surface. But, for the SMO device only involve two major key functions such receptor and transducer functions. For SMO, the free electrons easily flow after high temperature is applied to the sensor and then through grain boundaries of the SMO films. While in the atmosphere, on the SMO surface is where the oxygen absorbed and forming a potential barrier at the grain boundaries. After that, SMO surface forms charged oxygen and trapped electrons form the bulk material where the layer of charged electrons repels other electron from interacting the bulk film.

The depleted region of electron created and increased potential barrier at the grain boundaries. SMO have applied in detecting air pollutants for example sulfur dioxide gas. SMO detects sulfur dioxide and reduces in the environment. Same goes with H2S gas which this gas is very dangerous to human health, which if the concentration of this gas is above 250 ppm, the possibility for humans to get negative effect to their body and possibility to cause death. SMO has modified to selective detect H2S gas. Both semiconductor metal oxide sensor and solid-state gas sensor are a good choice to apply in detecting the pollutant gas to improve the environment before it is become worst.

Improve the Outcome

Using NonEngineering Approach Even though, China’s acid emission is higher than expected, their ammonia emission is still three times larger than NOx due to agricultural activities. In recent years, China’s local air has improved due to restrictions on the use of coal-fired household stoves in urban area to the country sides. The installation of scrubbers on coal-fired boilers also reduced air pollution in China. Due to acid rain, China had taken necessary step on environmental monitoring. General focus in national monitoring environment program Is focus on urban air quality and precipitation pH. Chinese and Norwegian are cooperating in this environmental monitoring project which is called Integrated Monitoring Program on Acidification of Chinese Terrestrial Systems. Five forest state in China was involved in this program which focusing in air pollution, perception composition, water and soil.

China’s government recognized the problem and take necessary action. China has developed the concept of an acid-rain control zone as priority in acid-rain reduction policy. Next, a campaign called West to East Electricity Transfer Project for Ginzhou is one of the government action on increasing electricity production. That is because Ginzhou is one of the poorest in China and many new coal-fired power plant built there as their source of electricity. However, the emission of coal-fired plant is not healthy.

Conclusion

Acid rain in China is caused by the largest usage of coal in their industrial area or domestic area. Increasing in coal combustion and increasing the number of vehicle are resulting the emissions of NOx. NOx and SO2 formed acid deposition and emitted to the atmosphere which is it is very dangerous to the human and may cause air pollution, hazy surrounding and acid rain. Fossil fuel also causing unhealthy China’s atmosphere from its acid decomposition.

There are two engineering solutions that focusing on detecting gas pollutants are stated which is developing semiconductor metal oxide sensor and solid-state gas sensor. Although the traditional technology detecting gas pollution is available which it is using infrared (IR) sensor, but SMO and solid-state gas sensor is better. IR sensor technology for gas detection is expensive, huge and complex, thus it would be difficult for the future generation to extend this pollutant detecting gas pollutant systems technology.

Гnlike SMO is very low cost, small size, measurement simplicity, durability, ease of fabrication and low detection limits or ppm level. Personally, SMO is a great solution to apply in conjunction to improve China environmental issue especially air pollution that will causes acid rain. The non-engineering solution had applied by China to improve this issue. China undergo environmental monitoring which China monitor some places to monitor its air quality and pH. For example, China-Norwegian Integrated Monitoring Program on Acidification of Chinese Terrestrial System. China also doing agricultural activities without failed that affecting the local air improved. Furthermore, restrictions on the use of coal-fired household stoves in urban area to the country sides also improved the air quality. Thus, engineering and non-engineering solution need to be worked together in all environmental issue so that it is under control.

Rain is a critical component in the process of the hydrological cycle. The water cycle is beneficial to all organism living on this planet. It brings purification and distribution of fresh water that can be used by all living organism. Apart from providing fresh water, it also played a pivotal role in regulating the earth temperature. Regulation of the temperature occurs when water in the sea, lake or any other water body evaporates bringing a cooling effect to our environment. The vapor condenses and rains completing the water cycle.

What is of great importance to these process is the effect it has on our ecosystem. Living things requires fresh water to survive, while most of the water found on earth is salty or in a state where purifications need to take place to be consumable. Ever since the rainwater has been the most purified source of water with a PH scale of 5.0, but thanks to anthropogenic activities, it is no longer the case. Rainwater is now full of all kind of impurities and poses a great all living things in one way or another. The most common of all these impurities is acidic components.

Acid rain is formed when Sulphur dioxide and nitrogen dioxide react with oxygen or water in the atmosphere. The product of this reaction is a substance that has a PH level of below 5.0 in the PH scale. It is introduced into the water bodies in form of rain, snow, fog or even dust. The key components of acidic rain .i.e. Sulphur dioxide and nitrogen dioxide are a byproduct of burning fossil fuels, gases realized by heavy equipment and Vehicles, industries and oil refineries. The change in Ph. level of water has had mostly a negative impact on the organism living in water. It has led to declining of the population of certain species living in water e.g. fish, crayfish and clamor cause some of them to disappear completely. Though another aquatic organism has either develop resistance or adapt to the changing environment some have flourished with the new condition. From the research carried out by a group of scientist on the effects of acid rain on a living organism, it’s clear that aquatic living organism is the one most affected by acidic rain. Below are the effects acidic rainwater has had on water living organism.

1. High concentration of methylmercury

Methylmercury is one of the most poisonous forms of mercury. It is widely known to cause brain and nervous system damage. Its formation is as a result of the reaction between bacteria and mercury in water or soils. The acidic rain that has the highest Sulphur concentration when it flows to the lakes, sea or any other large water body, contribute highly to the speeding up of conversion of mercury into methylmercury. These methyl mercury are consumed by an organism that is at the lower tier of the food chain. When top predators higher in the food chain feeds on them on large quantities, it accumulates on the fat cells until methyl mercury reaches a level that is harmful to the animals themselves and that’s why their population of the top predators is declining.

2. Declining population of an aquatic organism

The acidification of water bodies has had a great impact on marine organisms. Some of the notable consequences are depressing metabolic rates and lowering of immune response for most the water living organism have led to coral bleaching. And the population of most the marine organism is declining at an alarming rate. Even though some species have adapted to the changing environment, the family of shellforming animals and even planktonic organism are the most hit by the change in the PH level. There is also a risk of disappearing of a whole species in the near future as more water bodies turn acidic. The more the water becomes acidic it will become impossible for fish to lay and hatch their eggs and this will have a huge impact on the fish population. As the water PH level lowers down the consequence would have a ripple effect not only on marine but to the entire living things on earth.

3. Increasing the level of aluminum

When acidic rainwater flows through a clay soil, it leach’s aluminum and flows to the ocean, sea, lakes, and streams. As this process continues for some time, the water bodies become more concentrated with aluminum. These mineral call aluminum pose a great danger to the fish living on those water. They kill by arousing extra mucus formation on the water. These affect the ecosystem in the water, as more fish dies due to this toxic aluminum, another organism that depends on fish either increases population if they were being consumed by fish or decreases if fish were their food.

4. Lowering the amount of oxygen in the water

For all organism to survive they need oxygen. When this gas becomes scares, tissues and other body organs starts to fail to function. Acidic water that has its PH level below 3.0 tends to have low oxygen. Fish that live in these water are starved of oxygen and as result, their gills are affected. Mucus that grows on the gills of the fish also prevents fish from absorbing enough oxygen. It also affects the fish growth, some servers from stunt growth and thereby making them less competitive when looking for food.

5. Interfering with reproductive life-cycle.

Very low PH level causes chronic stress on most of the aquatic organism, these have caused fish to low weight. In the most case, fish are unable to lay eggs or they lay few eggs. The eggs laid are often a week or frail and they are easily damaged. The few eggs they have laid, have difficulty to be hatched. The fish lets that survived to be hatched are weak and too frail. The fish let have a soft membrane, when they are subjected to water that has high acid concentration, the membrane is damaged.

During normal rain pollutants are cleane . If rain fall continues rainwater clean the air from pollutants. Sulphat , ammonium and nitrate can be reduced by normal rain up to 30 to 73%. While the gases i.e. sulphur dioxide, Ammonia, Chlorine and NO2 can be decreased by 24 to 63%. The amount of NO2 in 72% areas of Lahore city is higher than standard values set by Pakistan and US EPA. These results are the indication of bad air quality in city.

To control acid rain there is a need to reduce amount of sulphur dioxide and oxides of nitrogen released into the atmosphere by using less energy and clean fuels (natural gas), by using catalytic converters and by flue gas desulphurization. Also acid rain can be reduced by fuel switching or scrubbing. Fuel switching is to limit the use of sources containing sulphur. Coal are switched to coal which emit less sulphur and in place of oil use gas or any other energy source such as gas boilers instead of oil boilers. Scrubbing is the use of electrostatic precipitators in which positively charged sulphur particles are attracted by negatively charged particles. To reduce NOx methods such as Selective Catalytic Reduction Process (SCR) are used. This method reduce NOx up To 80% . In automobiles NOx can be reduced by using Catalytic Converters. These catalyst reduce NOx by 3 ways of conversion of NOx:

• Conversion of NOx into N2 and O2;
• Conversion of CO into CO2;
• Conversion of hydrocarbons into CO2 and H2O.

Buffering Capacity

Many forests ,streams and lakes are not effected by acid rain because of soil of that area. In those areas soil an buffers the acid rain by neutralizing acidity of rain water in it. This capacity of soil depends on soil composition and thickness and also on bedrock under soil. In areas like mountainous parts of North East United States, the soil thickness is less and lack ability to neutralize the acid rain water. Hence these areas are vulnerable to harmful effects of acid rain.

Episodic Acidification

Melting of snow and heavy rain can result in episodic acidification. Lakes that do not normally have a increased level of acidity may experience some effects of acid rain for a short period of time. In this short period of time acidity of lake remain high and soil can’t buffet it. This short duration of higher acidity (lower pH) can result in a stress of ecosystem for short time. In this short time some species of plants and animals may be injured or even die.

Conclusion

Acid rain has many disaster effects in all over the world. Acid rain damage buildings and decrease their beauty of attraction acid rain also effects plants and trees and forests directly or indirectly. Acid rain damage chlorophyll in plants due to which their photosynthesis process in effected and plant die. Acid rain in human cause asthma, cough, eyes infection, nose irritation etc. Due to Acid rain pH of water bodies increased above average level and result in death of fish and other aquatic animals and plants. Acid rain can be controlled by different programs and awareness among people about it causes. We can control acid rain by using clean fuel in automobiles and industries built outside of cities and their waste should be disposed for prevention from its effects.

During normal rain pollutants are cleane . If rain fall continues rainwater clean the air from pollutants. Sulphat , ammonium and nitrate can be reduced by normal rain up to 30 to 73%. While the gases i.e. sulphur dioxide, Ammonia, Chlorine and NO2 can be decreased by 24 to 63%. The amount of NO2 in 72% areas of Lahore city is higher than standard values set by Pakistan and US EPA. These results are the indication of bad air quality in city.

To control acid rain there is a need to reduce amount of sulphur dioxide and oxides of nitrogen released into the atmosphere by using less energy and clean fuels (natural gas), by using catalytic converters and by flue gas desulphurization. Also acid rain can be reduced by fuel switching or scrubbing. Fuel switching is to limit the use of sources containing sulphur. Coal are switched to coal which emit less sulphur and in place of oil use gas or any other energy source such as gas boilers instead of oil boilers. Scrubbing is the use of electrostatic precipitators in which positively charged sulphur particles are attracted by negatively charged particles. To reduce NOx methods such as Selective Catalytic Reduction Process (SCR) are used. This method reduce NOx up To 80% . In automobiles NOx can be reduced by using Catalytic Converters. These catalyst reduce NOx by 3 ways of conversion of NOx:

• Conversion of NOx into N2 and O2;
• Conversion of CO into CO2;
• Conversion of hydrocarbons into CO2 and H2O.

Buffering Capacity

Many forests ,streams and lakes are not effected by acid rain because of soil of that area. In those areas soil an buffers the acid rain by neutralizing acidity of rain water in it. This capacity of soil depends on soil composition and thickness and also on bedrock under soil. In areas like mountainous parts of North East United States, the soil thickness is less and lack ability to neutralize the acid rain water. Hence these areas are vulnerable to harmful effects of acid rain.

Episodic Acidification

Melting of snow and heavy rain can result in episodic acidification. Lakes that do not normally have a increased level of acidity may experience some effects of acid rain for a short period of time. In this short period of time acidity of lake remain high and soil can’t buffet it. This short duration of higher acidity (lower pH) can result in a stress of ecosystem for short time. In this short time some species of plants and animals may be injured or even die.

Conclusion

Acid rain has many disaster effects in all over the world. Acid rain damage buildings and decrease their beauty of attraction acid rain also effects plants and trees and forests directly or indirectly. Acid rain damage chlorophyll in plants due to which their photosynthesis process in effected and plant die. Acid rain in human cause asthma, cough, eyes infection, nose irritation etc. Due to Acid rain pH of water bodies increased above average level and result in death of fish and other aquatic animals and plants. Acid rain can be controlled by different programs and awareness among people about it causes. We can control acid rain by using clean fuel in automobiles and industries built outside of cities and their waste should be disposed for prevention from its effects.