The harm of acid rain

The harm of acid rain

Acid rain has become one of the most serious regional environmental problems in the world today. From a broader perspective, the term acid rain can be extended to acid precipitation. Acid deposition means that the acid in the atmosphere migrates to the ground through precipitation (such as rain, fog, snow, etc.), or directly migrates to the ground under the action of an acid gas mass airflow. Generally, the research on acid deposition mainly focuses on acid rain. The first analysis and monitoring of rainwater in the world was in 1850. The natural source of sulfur dioxide is volcanic eruptions. In the northern hemisphere, the amount of sulphur dioxide emitted by human activities is greater than that of natural emissions. In the southern hemisphere, the opposite is true.

Rainfall with a pH lower than 5.6 is usually called acid rain. This natural acidity was greatly enhanced in the 20th century due to the increase of pollutants emitted by humans into the atmosphere. The pH value changed from 4 to 4.5. Among the pollutants that can form acid rain, the most important ones are the emissions from fossil fuels during the combustion process. SO 2 and nitrogen oxide gas. Such as petroleum refining, power generation, industrial and civil fuel or coal-fired heating. These major industrial production and energy conversion sectors are the largest sources of SO 2 generation and emissions. The more energy required, the more serious the pollution caused. A 1,000MW coal-fired power station generates 6.6Tw.h throughout the year, which consumes 6.5Mt of oxygen and 2.5Mt of coal to release 7.8Mt of CO 2 , 40,000t of SO 2 and 10,000t of NO2.

These gases chemically react with water vapor to form acidified soil and water such as sulfuric acid and nitric acid.

Acid rain can damage aquatic ecosystems and terrestrial ecosystems in different ways, and acid rain can also accelerate the corrosion of building materials. Acid rain has acidified rivers and lakes, and aquatic ecosystems have become disordered. During the most severe period of acid rain, 1750 of the approximately 5,000 lakes in southern Norway caused fish and shrimps to disappear due to excessive acidity; 20,000 of Sweden’s 90,000 lakes have been affected by acid rain to varying degrees. Thousands of lakes in Canada and the United States have been acidified, which has become serious enough to threaten the survival of certain organisms. The United States has reported that at least 1,200 lakes have been acidified, and the 8500 lakes sampled in Canada have all been acidified.

In the United States, acid rain in the Northeast, where the industry is highly concentrated, is gradually spreading to densely populated areas in the west and important nature reserves. A joint acid rain test conducted by the U.S. World Resources Institute and the University of California, Berkeley on the west showed that “the entire west’s precious water resources, forestry resources, 11 national parks, and millions of acres of natural areas are under the prestige of acid rain. “.

Acid rain can also burn crops or reduce production. The research results of American scientists show that corn that has been exposed to acid rain immediately after pollination produces fewer grains than corn that has not been exposed to acid rain. Moreover, the more acidic components contained in the rain, the fewer particles will be formed. Sometimes, after an acid rain, hundreds of acres of crops can be burnt.

Acid rain not only seriously harms the natural environment, but also has become a major factor in harming human health. According to the calculation of the US government, the death toll caused by acid rain and sulfur oxide pollution in 1980 accounted for 2% of the national death toll, which is equivalent to 51,000 deaths in the United States due to air pollution.
The corrosive effect of acid rain has also accelerated the damage and shortened service life of materials such as buildings, bridges, dams, industrial equipment, water supply pipe networks, hydroelectric generators and communication cables, and severely damaged historical buildings, sculptures and other cultural monuments.

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