Air pollution has had adverse effects on the people of the US. Indoor air pollution may trigger allergic reactions in sensitive individuals, including asthma, respiratory-tract infections, emphysema, cardiovascular diseases and bronchitis (Phalen and Phalen 30). Some effects may be fatal or severely debilitating such as cancer, heart disease and some respiratory diseases and may only be noticed after repeated or long periods of exposure. Treatable effects include irritation of the nose, eyes and throat, dizziness, fatigue and headaches. The effects of outdoor pollutants include permanent lung damage, irritation of the respiratory system, asthma attacks, susceptibility to respiratory infections and acute bronchitis (EPA). Some have severe effects such as lead which accumulates in bones and adversely affects kidney function, the nervous system, cardiovascular system as well as developmental and reproductive systems. Environmentally, air pollution is responsible for climate change and global warming through the greenhouse effect. It is important that air pollution is reduced to levels that have minimal environmental and health effects. Statistics from EPA show significant reduction of the emission of pollutant gases in the period between 2000 and 2012. Carbon monoxide emission reduced by 51%, lead by 50%, while that of sulfur dioxide reduced by 66%. In line with this, EPA promulgates regulations that should be followed by individual citizens, businesses, communities and states.