The effects of air pollution are not confined to urban areas. Negative impacts also occur in rural and wilderness areas through wind, illustrating the complexity of dealing with this environmental issue. Air pollution not only affects animals and plants, but it can also harm soils and water resources. It can also trigger other reactions within the environment.
Air pollution affects plants by slowing the rate of photosynthesis, according to a 2005 study published in Encyclopedia of Plant and Crop Science. Photosynthesis is the process where plants make food. Specifically, air pollution shrinks the size of a plant's stomata or pores, diminishing its ability to carry out gas exchange. If a plant cannot get enough carbon dioxide, photosynthesis and plant growth slow. Some toxins such as ozone and acid rain can physically injure plants.
Air pollution creates a domino effect. The toxins released into the air and water through precipitation can accumulate in the tissues of animals lower down the food chain. When predators feed on these affected animals, concentration levels of the contaminants increase within their bodies. Over time, these concentrations can reach lethal levels as the predators continue to feed. In this way, the effects of air pollution on animals become more widespread within the ecosystem.
Acidification of the Environment
Some toxins such as mercury persist in the environment, meaning that it does not degrade, so negative effects can continue to affect plant and animal populations. Contaminant concentrations can increase, creating toxic environments, such as acid rain, that are unable to support plant or animal life. Acid rain forms when moisture in the atmosphere combines with toxic emissions through a chemical reaction fuelled by the sun. Over time, the acidic precipitation will acidify soils and waters, affecting plant and animal life. A survey conducted by the U.S. Environmental Protection Agency, or EPA, found about 580 of the streams in the mid-Atlantic coastal plain were negatively affected by acid rain.
Some organisms are more sensitive to the effects of air pollution, making them more vulnerable. The permeability of the skin of amphibians such as frogs or toads, for example, increases their risk of exposure to toxins in the air and water. In addition, some areas are more vulnerable to the effects of air pollution such as acid rain. The EPA identified several such areas within the United States, including the Adirondacks and Catskill Mountains in New York state.
Air pollution is not a problem without a solution. Rather, strides have been made in recent years to reduce pollution and lessen its effects on animals and plants. Sulphur dioxide emissions are more than 70 per cent lower in 2008 than in 1980, according to figures from the EPA. Programs such as the EPA's Acid Rain Program protect the health of ecosystems and its plant and animal life.
- "Encyclopedia of Plant and Crop Science"; Robert L. Heath; July 2005
- U.S. Environmental Protection Agency: Environmental Effects
- U.S. Environmental Protection Agency: Effects of Acid Rain - Surface Waters and Aquatic Animals
- National Zoo: Early Warning Sign?
- U.S. Environmental Protection Agency: Sulfur Dioxide