When people breathe dirty air, pollutants may come into direct contact with their lungs.
Polluted air can burn eyes, irritate throats and affect breathing.
Some chemicals emitted to the air can cause adverse health effects if released in large enough quantities or over a long enough time. These health effects could include cancer, birth defects, damage to the brain, nervous system or respiratory tract and even, in rare instances, death. Acid rain can destroy lakes, rivers and the organisms that inhabit them. Certain compounds degrade the ozone layer above the earth, which serves as a filter for the sun's harmful ultraviolet rays. The thinning of this upper level atmospheric ozone layer may lead to higher rates of skin cancer and eye damage for both humans and animals.