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Acid Rain & Its Effects on the Environment

The Environmental Protection Agency (EPA) defines acid rain as "a mixture of wet and dry deposition from the atmosphere containing higher than normal amounts of nitric and sulfuric acids." Acid rain is the consequence of both natural and man-made activities such as the emissions from volcanoes, decaying vegetation and emissions of sulfur dioxide and nitrogen oxides from the combustion of fossil fuel. Acid rain has several negative effects.

  1. Surface Waters

    • Acid rain affects aquatic environments such as streams, marshes and lakes. This causes a condition known as chronic acidity, which means that water has a constant low pH level. Distilled water, or water with no carbon dioxide, has a neutral pH of seven; any liquid with a pH less than seven is acidic whereas any liquid with a pH more than seven is alkaline or basic. Acid rain causes a kind of domino effect that ultimately leads to a reduction in fish population numbers or even complete elimination of fish species from a body of water. This affects the food chain and reduces biodiversity. At pH 5, it is hard for fish eggs to hatch; at even lower pH levels, some older fish will die, which is why some acid lakes have no fish.

    Forests

    • Acid rain is responsible for slow growth in some forests. Scientists have noted that acid rain causes the leaves and needles on trees to turn brown and fall of instead of thriving. In some serious cases, whole trees or certain areas of the forest just die off as a result of the effect of acid rain. According to the EPA, acid rain is responsible for forest and soil degradation in parts of the eastern U.S., especially in high-elevation forests, including the Appalachian Mountains from Maine to Georgia and Great Smoky Mountain National Park.

    Materials

    • Acid rain leads to the corrosion of metals like bronze and the weathering of stone, marble and paint. Acid rain can also deface the surface of buildings, leading to an increase in maintenance costs. This effect can also be seen in the automotive industry, forcing manufacturers to use acid-resistant paints on new vehicles.

    Visibility and Human Health

    • Acid rain contributes to a reduction in visibility due to the sulfates and nitrates that form in the atmosphere from acid rainfalls. The EPA reports that sulfate particles are responsible for 50 to 70 percent of the reduction in visibility in the eastern part of the U.S. The EPA has also discovered a direct correlation between the inhalation of fine sulfates and nitrate particles from acid rains and illness and even premature death due to lung and heart disorders such as bronchitis and asthma.

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