Acid Rain

Acid Rain

Acid rain is the term used to describe the deposition of acidic air pollution. Although some air pollutants fall directly back to Earth, a lot of it returns in rain, snow, sleet, hail, mist or fog, hence the term "acid rain".
When power stations, factories, houses and cars emit pollution into the air, it contains chemicals known as sulphur dioxide and nitrogen oxides. These chemicals may either fall directly back to the Earth due to gravity, or they may mix with water (moisture) in the air to form acids. Once acids have formed, they can be transported long distances by the wind before being deposited in rain, snow or hail. This is what we commonly call acid rain.

Acid rain can have harmful impacts on the environment. It affects freshwater lakes and the wildlife that depend upon them. It also affects trees by harming leaves and soil, and it damages buildings made of limestone and marble.
During the 1970 and 1980s acid rain become a worldwide problem. In countries such as Britain and America, there are many power stations and factories that produce a large amount of pollution. This pollution is released several hundred feet up through tall chimneys to keep the air at ground level cleaner. It is then blown by the wind and deposited as acid rain in countries such as Canada, Norway, Sweden and Finland, which lie hundreds of miles downwind from the source of the pollution.
Definition
Most rainfall is generally slightly acidic due to the carbonic acid from carbon dioxide in atmosphere. But 'acid rain' is caused when sulfur (sulphur) dioxide and nitrogen oxides (from automobile exhausts and industrial emissions) are washed out from the atmosphere by rain as weak sulfuric (sulphuric) and nitric acid. Acid rain can cause serious damage to crops, and leaches calcium ions fromsoil and plant leaves causing an ionic imbalance.

Meaning

Acid rain is a rain or any other form of precipitation that is unusually acidic, meaning that it possesses elevated levels of hydrogen ions (low pH). It can have harmful effects on plants, aquatic animals and infrastructure. Acid rain is caused by emissions of sulfur dioxide and nitrogen oxide, which react with the water molecules in the atmosphere to produce acids. Some Governments have made efforts since the 1970s to reduce the release of sulfur dioxide and nitrogen oxide into the atmosphere with positive results. Nitrogen oxides can also be produced naturally by lightning strikes, and sulfur dioxide is produced by volcanic eruptions. The chemicals in acid rain can cause paint to peel, corrosion of steel structures such as bridges, and weathering of stone buildings and statues.

History

The corrosive effect of polluted, acidic city air on limestone and marble was noted in the 17th century by John Evelyn, who remarked upon the poor condition of the Arundel marbles. Since the Industrial Revolution, emissions of sulfur dioxide and nitrogen oxides into the atmosphere have increased. In 1852, Robert Angus Smith was the first to show the relationship between acid rain and atmospheric pollution in Manchester, England.
Though acidic rain was discovered in 1853, it was not until the late 1960s that scientists began widely observing and studying the phenomenon. The term "acid rain" was coined in 1872 by Robert Angus Smith. Canadian Harold Harvey was among the first to research a "dead" lake. Public awareness of acid rain in the U.S increased in the 1970s after The New York Times published reports from the Hubbard Brook Experimental Forest in New Hampshire of the myriad deleterious environmental effects shown to result from it.

Adverse effects

This chart shows that not all fish, shellfish, or the insects that they eat can tolerate the same amount of acid; for example, frogs can tolerate water that is more acidic (i.e., has a lower pH) than trout.
Acid rain has been shown to have adverse impacts on forests, freshwaters and soils, killing insect and aquatic life-forms as well as causing damage to buildings and having impacts on human health.

Surface waters and aquatic animals

Both the lower pH and higher aluminum concentrations in surface water that occur as a result of acid rain can cause damage to fish and other aquatic animals. At pHs lower than 5 most fish eggs will not hatch and lower pHs can kill adult fish. As lakes and rivers become more acidic biodiversity is reduced. Acid rain has eliminated insect life and some fish species, including the brook trout in some lakes, streams, and creeks in geographically sensitive areas, such as the Adirondack Mountains of the United States. However, the extent to which acid rain contributes directly or indirectly via runoff from the catchment to lake and river acidity (i.e., depending on characteristics of the surrounding watershed) is variable. The United States Environmental Protection Agency's (EPA) website states: "Of the lakes and streams surveyed, acid rain caused acidity in 75% of the acidic lakes and about 50% of the acidic streams".

Affected areas

Places significantly impacted by acid rain around the globe include most of eastern Europe from Poland northward into Scandinavia,the eastern third of the United States, and southeastern Canada. Other affected areas include the southeastern coast of China and Taiwan.

The Advantages of Acid Rain

Acid rain comes in the form of rain, fog, smog and dry depositions, and it harms forests, kills fish and erodes rocks and buildings. It is caused by excessive emissions of sulfur dioxide and nitrogen oxide compounds from industrial and natural sources. About two-thirds of sulfur dioxide and one-quarter of nitrogen oxides come from fossil-fuel-burning power plants. Some environmental studies indicate that the effects of acid rain are complex and include positive effects on global warming and improvement of forests.

Forests

A 20-year-long study by scientists at Michigan Technological University School on the hardwood forests of Michigan found that acid rain, together with modest increases in temperature, makes forests more productive. Researchers measured nitrogen deposition by acid rain and found that trees store more carbon when the soil contains more nitrogen compounds, as long as there is enough moisture. Therefore, the increased growth rate and greater ability of trees to store carbon dioxide may offset some of the negative effects of acid rain on forests, such as damage to tree foliage.

Complex Effects of Acid Rain

Acid rain clearly has negative effects on the environment, but the beneficial effects of acid rain must enter into future predictions of its role in environmental damage and global warming. A computer model, created at NASA's Goddard Space Flight Center, predicts that the sulfur dioxide in acid rain will continue to suppress methane production by wetlands well into 2030. Although nitrogen oxide deposition by acid rain may have positive effects on forest trees, highly polluted acid rain damages trees and harms some animal species.

Advantageous Effect?

These scientists claim that acid rain can reduce methane outputs from wetlands. Wetlands are still the single largest source of methane production. Scientists experimented with applying sulphates in the amounts found in acid rain to wetland areas. They found this reduced methane emissions by 30-40 percent. When they expanded the results by using computer models, they found that acid rain can reduce methane below pre-industrial levels. If these studies can be duplicated or other studies can confirm similar results, then acid rain may be working to balance the effects of global warming.

Causes, Effects, And Solutions of Acid Rain

"Acid Rain,"  or more precisely acid precipitation, is the word used to describe rainfall that has a pH level of less than 5.6.  This form of air pollution is currently a subject of great controversy because of it's worldwide environmental damages.  For the last ten years, this phenomenon has brought destruction to thousands of lakes and streams in the United States, Canada, and parts of Europe.  Acid rain is formed when oxides of nitrogen and sulfite combine with moisture in the atmosphere to make nitric and sulfuric acids.  These acids can be carried away far from its origin.  This report contains the causes, effects, and solutions to acid rain.
The two primary sources of acid rain are sulfur dioxide (SO2), and oxides of nitrogen (NOx).  Sulfur dioxide is a colourless, prudent gas released as a by-product of combusted fossil fuels containing sulfur.  A variety of industrial processes, such as the production of iron and steel, utility factories, and crude oil processing produce this gas.  In iron and steel production, the smelting of metal sulfate ore, produces pure metal. This causes the release of sulfur dioxide.  Metals such as zinc, nickel, and copper are commonly obtained by this process.  Sulfur dioxide can also be emitted into the atmosphere by natural disasters or means.  This ten percent of all sulfur dioxide emission comes from volcanoes, sea spray, plankton, and rotting vegetation.  Overall, 69.4 percent of sulfur dioxide is produced by industrial combustion.  Only 3.7 percent is caused by transportation
The other chemical that is also chiefly responsible for the make-up of acid rain is nitrogen oxide.  Oxides of nitrogen is a term used to describe any compound of nitrogen with any amount of oxygen atoms.  Nitrogen monoxide and nitrogen dioxide are all oxides of nitrogen.  These gases are by-products of firing processes of extreme high temperatures (automobiles, utility plants), and in chemical industries (fertilizer production).  Natural processes such as bacterial action in soil, forest fires, volcanic action, and lightning make up five percent of nitrogen oxide emission.  Transportation makes up 43 percent, and 32 percent belongs to industrial combustion.
Nitrogen oxide is a dangerous gas by itself.  This gas attacks the membranes of the respiratory organs and increases the likelihood of respiratory illness.  It also contributes to ozone damage, and forms smog.  Nitrogen oxide can spread far from the location it was originated by acid rain.
As mentioned before, any precipitation with a pH level less than 5.6 is considered to be acid rainfall.  The difference between regular precipitation and acid precipitation is the pH level.  pH is a symbol indicating how acidic or basic a solution is in ratios of relative concentration of hydrogen ions in a solution.  A pH scale is used to determine if a specific solution is acidic or basic.  Any number below seven is considered to be acidic.  Any number above seven is considered to be basic.  The scale is color coordinated with the pH level.  Most pH scales use a range from zero to fourteen.  Seven is the neutral point (pure water).  A pH from 6.5 to 8, is considered the safe zone.  Between these numbers, organisms are in very little or no harm.
Conclusion
In conclusion, this research project, Ryegrass’s ability to effectively decontaminate soil from strong pH levels of Acid Rain, has provided evidence that it is possible to use Ryegrass as an environmental retro-active solution of Acid Rain soil contamination. According to the results presented in the spread sheets, it is evident that both Ryegrass and Perennial Ryegrass assist in absorbing low pH levels of sulfuric and nitric acids out contaminated soil. The supporting evidence includes the change in the stem and root color in both types of Ryegrass, a change in the node fixture in Perennial Ryegrass, and most importantly a change a rise in the pH of the acid rain contaminated soil. These results were strongly apparent in both the sulfuric and nitric acids with pH’s of 2.0 and 2.5. The roots color would change from white, observed in the control group, to yellow, and in extreme cases an orange, in the experimental group. The stem color change was not as drastic as seen in the roots but it was evident in the Ryegrass that the low pH levels of acid were effecting the production of chlorophyll. Although, these surface observations merely suggest what the environment has already concluded, acid rain contaminates, the Ryegrass with closer observation proved otherwise. Despite the color change, the Ryegrass appeared healthy; the turgor pressure maintained a hyposmotic environment. It appears that the intake of the acid into the vascular tissue of the plant was not effecting the entire production of food, or photosynthesis. This statement is feasible because during the observations of these Ryegrass plants over a period of time the Ryegrass never died despite the color change.
Secondly, the node change was unexpected in the Perennial Ryegrass used in the further study. A comparison between a bent node and a straight node can be viewed on the web page found on the computer. A node is a joint. In the control group the nodes were joints lacking a severe directional change. In laymen’s terms they simply remained vertical. However, the Perennial Ryegrass that was grown in contaminated soil with a pH of 2.0 or 2.5 showed a severe directional change at the nodes.