Infopedia 2.0. Softkey Multimedia Inc, 1995

Microsoft Encarta 97. Microsoft, 1997

Grolier Interactive. Grolier 98. Grolier Interactive Inc., 1998

Here are the sites that we looked at and used information from.

Environmental Protection Agency
http://www.epa.gov/

GreenPeace
http://www.greenpeace.org/

Information about Air
http://www.air.org/