The clean air act is to achieve dramatic air reductions in air pollution, in order to protect the ozone layer, reducing acid rain and toxic pollutants, and improve air quality. Not only to address air quality, but to address climate change, reduce our carbon emissions, and prevent the ozone layer depletion. Since the 1990’s amendment, there has been regulations later down the line to further improve the policies. In 1991, 41 areas had unhealthy levels of carbon monoxide pollution but regulated to meet standards in 1997 and 2006. In 2012, Mercury and Air Toxics Standards are cutting toxic emissions from power plants and vehicles.