Environmental pollution is contamination of air, water and land from man-made waste. Pollution leads to depletion of the ozone layer, global warming and climate change. Air pollution is the release of chemicals and particles into the atmosphere. Water pollution includes surface runoff, leakage into groundwater, liquid spills, wastewater discharge and littering. If toxins are spilled on the ground or if an underground storage tank leaks, soil can become contaminated. Well known contaminants include herbicides and pesticides. Toxic waste is waste material, often in chemical form, which pollutes the natural environment and contaminates groundwater.
Other types of pollution include ocean pollution and noise pollution. Environmental pollution can have a deadly effect on humans and ecosystems. For example, cigarette smoke, including second-hand smoke, causes cancer, emphysema, stroke and heart attack. Drinking water can become contaminated by untreated sewage, rashes and skin problems occur due to oil spills, while excessive noise can cause hearing loss. The U.S. Environmental Protection Agency (EPA) was established in 1970 to put a limit on the amount of pollutants in the air. Congress passed the Clean Air Act in 1963, the Noise Control Act in 1972 and the Clean Water Act in 1977. Pollution is a bigger concern in other parts of the world, especially developing countries. Time Magazine reported in 2007 that the most polluted spots in the world included China, India, Peru and Russia.
