For the more information about water resources in the National
Park Service, please visit http://www.nature.nps.gov/water/.
Clean Air Act The Clean Air Act of 1970 (as amended) regulates
airborne emissions of a variety of pollutants from area,
stationary, and mobile sources. The 1990 amendments to this act
were intended primarily to fill the gaps in the earlier
regulations, such as acid rain, ground level ozone,
stratospheric ozone depletion, and air toxins. The amendments
identify a list of 189 hazardous air pollutants. The EPA must
study these chemicals, identify their sources, determine if
emissions standards are warranted, and promulgate appropriate
regulations. Last Updated: March 02, 2012