Acid rain is any form of precipitation that consists of high levels of acidic compounds with a pH of 5.5 or low. Formation of acid rain occurs when nitrogen oxides and sulfur dioxides are released to the atmosphere where they react with water forming nitric and sulfuric acids (1). They can rise to very high levels and disperse to long distances due to their ability to dissolve in water easily which makes them easier to be carried by wind. They, then, combine with other chemicals including oxygen and water resulting to the formation of acidic substances most of which are environmental pollutants (2).
Over the past years, activities by man have been a major cause of acid rain. Such activities have caused the release of various chemicals to the atmosphere that has caused diverse changes to the composition of acidic rain (2). Majority of these chemicals are as a result of burning of fossil fuels, especially in the generation of energy (1). Charcoal burning and eruptions from volcanoes have also had a lot of contribution in the formation of acid rain due to the release of various oxides during the process.
Other sources of nitrogen and sulfur oxides, which are the chief causes of acid rain, are exhausts from automobiles. In other cases, normal precipitation may fall on surfaces such as water sources including lakes and streams, soil or bedrock material that may be too acidic to counteract an alkaline precipitation. Such occurrence converts normal rain to acidic rain (3).
Acid rain is better described as acid depositions which may either be wet or dry. A wet deposition is described by all forms of precipitation that are acidic including rain, fog or even snow. They all have adverse effects to both plants and animals especially those that depend on water. The extent of these effects depends largely on the amount of acid present in the water (2). It is also determined by the chemical composition of the soil and that of other living things involved.
A dry deposition is used to describe the fall of acidity back to the surface through the release of gases and particles that are acidic. When these particles and gases are blown by the wind from the surface, they find their way onto buildings and other surfaces. During rain seasons, these particles may be carried away by normal rain water changing it to acid rain (1). Alternatively, the particles may be washed by original acid rain making the situation even worse.
Effects of acid rain
Acidic rain contaminates the environment and makes it difficult for organisms to survive. In most cases, organisms either experience retarded growth while in other cases; the organisms may die due to harsh living conditions.
The most felt effects of acid rain are on aquatic environments such as lakes and streams. In these ecosystems, acidic water from acidic rain pollutes the water that aquatic organisms depend on for survival. This may lead to death of these organisms and thus biological diversity in these aquatic environments is affected. Though most water environments have a neutral pH, some are normally acidic without the effect of acid rain. However, living organisms that live in the latter ecosystems are adapted to the particular level of acidity that is characteristic of their ecosystem. Any significant changes to the pH of these ecosystems may be disastrous to the living organisms living in them. This is particularly the case in the event the ecosystem is contaminated by acidic rain which lowers its pH making the environment unfavorable for the organisms (2).
Acidic rain has devastating effects on most ecosystems on the earth’s surface. As it has been stated in the discussion above, water-based ecosystems are the most vulnerable to acidic rain due to their ability to dissolve the rain quickly in them. Additionally, among the water-based ecosystems, the most affected are those that lack buffering capacity which is the ability to neutralize acidic substances. As a result of this inability, the pH value of the water decreases and thus the water becomes acidic.
This is normally the case in aquatic environments whose pH is already low before the acidic rain contaminates them. Since their pH is already low, they are unable to neutralize the acidic rain and thus the water gets more acidic endangering the lives of organisms in the ecosystem. Contrarily, an aquatic environment may be having a substantially high pH before the occurrence of the acidic rain. This gives it buffering ability and thus the effects of the acidic rain on the organisms in the ecosystem will be mitigated.
The acidity that acidic rain gives to aquatic environments causes the discharge of aluminum from soil into the water. Being highly toxic, aluminum causes harmful effects on aquatic animals which may even kill them. In other cases, the aquatic animals are may not be killed instantly, instead the high level of aluminum combines with the low pH causing a lot of stress to the animals (1). This leads to a decrease in body mass and size of fish as well as the ability to fight for food, oxygen and habitat.
However, some plant and animal types have the ability to withstand acidic water. Those that are sensitive to acidic conditions are affected as the pH level decreases. The younger species are the most affected lowering the chances of fish eggs to hatch. The change in the pH levels also leads to lack of adequate calcium in fish which may cause deformation of their bones and weak spines (2).
Researchers have confirmed that acid rain has, over the years, had negative effects on forests. The most common effect that acidic rain has on forests is the fact that forests that are exposed to acidic rain have a characteristic slow growth. In other cases, forests may be adversely affected by acid rain, making vegetation to dry or rot. Forests are also affected indirectly by acid rain through degradation of soil when the acidic rain water dissolves in the soil. The dissolution of acidic rain in the soil normally dissolves nutrients that are required by the trees for their growth and thus these nutrients become unavailable to the trees. Forest trees are affected directly by acid rain through the damage of the leaves which in most cases turn brown in color. This results to inadequate nutrient supply to trees since the synthesis of organic materials takes place in the leaves through the process of photosynthesis (2).
As result, the plant becomes weak and more susceptible to bad weather and insects. The trees ultimately get infected with diseases and die. Toxic substances may also be released into the soil which collaborates with the acidic condition to harm the trees. When the chemical composition of forest floor lacks the ability to neutralize acids, its effects gets worse. However, limestone may occur naturally in the forest floor and due to its alkaline nature, it neutralizes the acidity caused by acid rain. In this case, trees will be normal as if the rain that has fallen is not acidic.
A lot of damage in the automotive industries has been reported to occur as a result of air pollution which has increased over the years due to various activities by man. Acid rain has been implicated as a major pollutant that causes permanent damage to different types of automotives. The evaporation of the acid water is what, actually, causes damage to automotive coatings. They do so by accelerating the rusting of automobiles. Damaged coatings have dark colored patches which are irregular in shape.
Metals such as bronze, a tough material, are corroded by acid rain water especially by the dry deposition. Different types of stones including limestone have been deteriorated by the effect of acid water. The overall result is the reduction of value in buildings and other objects that are constructed using these kinds of materials. When dry depositions fall on structures and other surfaces, they cause dirt on them and this calls for higher maintenance expenses (3).
Acid rain affects human health in different ways. Emissions of sulfur and nitrogen oxides to the atmosphere have contributed largely to problems related to vision. In most cases they result to short sightedness and unclear vision. Dry airborne depositions may cause damage to the respiratory system and this may result to the dysfunction of the lungs especially for those with breathing difficulties. When these pollutants that occur in form of gases are inhaled, they may cause the development of asthma or bronchitis and other respiratory diseases. In other cases, emissions from sulfur and nitrogen oxides may irritate the eyes and nostrils.
Death may even occur in cases of severe asthma. Leakage of toxic compounds ends up contaminating drinking water sources and causes vomiting to individuals or poisoning by the metals present in water. Edible fish usually get contaminated especially by aluminum and mercury. Consumption of such fish leads to poisoning and nerve or brain damage due to mercury accumulation. This effect is irreversible and may result to death (2).
Acidic rain has had damaging effects on infrastructure. As stated it damages automobiles, buildings and paints. In addition to the stated materials, acidic rain also damages cultural heritage like sculptures and statues that are made of materials that can be affected by acidic conditions. To illustrate the effect that acidic rain has on non-aquatic organisms, consider a study that was carried out on birds that nest on trees.
This study showed that birds in the Netherlands were seriously affected by acidic rain during reproductions. The eggs laid by birds were observed to have a defective tendency of close to half. The eggs were characterized by poor quality with weak shells and losing the average weight (2). It is thus evident that acidic rain affects both plants and animals badly and it is in the interest of every one of us to try his/her best to find a solution to the problem.
Ways of reducing acid rain
Cleaning up exhaust pipes
The burning of fossil fuels such as charcoal is a major contributor to acid rain. Other sources of energy associated with the same are natural gas and oil. The burning of these fuels emits nitrogen oxide and sulfur dioxide which react with air and other compounds to form acid rain (1). The effects of acid rain can be reduced by burning coal that contains small amounts of sulfur. Coal may also be washed specifically with scrubbers which remove the sulfur dioxides from the gases by chemical processes. Other devices which are similar to converters may be used to reduce the emissions of nitrogen oxides from automobiles (2).
Use of alternative sources of energy
Nuclear and hydropower energy can be used instead of energy from coal. Alternatively, wind, geothermal and solar energy can also be used because they are cheaper and eco-friendly. This ensures that less acidic gases are emitted to the atmosphere hence reducing levels of acidic rain (2).
Conservation of energy
The levels of acidic rain can also be reduced by proper use of energy at home or at the work place. People should, thus, make an effort to share automobiles when they are visiting the same place in order to reduce acidic-gas emissions and save energy (3). We can also conserve household energy and thus less energy will be generated which, in turn, will reduce the levels of acidic gases in the atmosphere. This can be done by employing basic energy conservation techniques such as ensuring that the water heater in the bathroom is properly insulated and turning off electronic equipment after using them to consume less electricity (2).
As discussed, acid rain has adverse effects to our lives. In order to curb these effects, we need to be informed on the causes and effects of acid depositions, especially the activities carried out by man that contribute to the same. There is also the need to understand the environmental changes that are brought by these acidic pollutants in order to come up with reliable solutions. Besides lack of knowledge, other people are aware of the facts about acid rain but they just ignore it.
Acid depositions, both wet and dry, get deeper into objects and soil. It is, therefore, of essence for people to shun ignorance and engage in activities that can restore the damaged environment. The best method of restoring such an environment is liming. Additionally, affected objects should be washed to remove sulfur compounds in order to prevent the buildup of pollutants. This involves adding limestone to acidic lakes to neutralize the acidity. The advantage of lime is that it does not kill fish thus allows the natural habitants to survive in the water. It is also wise to add the lime repeatedly to prevent the water from getting back to the initial acidic condition.
As efforts are made to reduce the effect of acid depositions, scientists should assess the progress of the process to ensure a sustainable solution is achieved. Individuals should actively take part by using energy properly and making use of alternative sources of energy that do not cause harm to the environment. In case of burning coal, the involved party should make sure that he/she uses coal that contains low levels of sulfur. It is also advisable for people carpool. Maintenance of all vehicles is necessary as well as buying those vehicles that emit low levels of nitrogen and sulfur oxides.
Environmental Protection Agency. 2010. Web.
Park, Chris, Acid Rain: rhetoric and reality, Barnes & Noble, California, 1997. National Geographic Society. Web.