Plain English Guide to the Clean Air Act
This EPA web site explains air pollution and the Clean Air Act in "plain English."
http://www.epa.gov/oar/oaqps/peg_caa/pegcaain.html

USGS Acid Rain
This web site provides recent measurements of precipitation pH.
http://h2o.usgs.gov/nwc/NWC/pH/html/ph.html

The Asbestos Informer
Sponsored by the U.S. EPA, this web site provides basic information about asbestos, its uses, the potential health risks associated with exposure to asbestos fibers, and asbestos regulations.
http://www.epa.gov/region4/air/asbestos/inform.htm
For additional information on asbestos see:
http://www.epa.gov/docs/region04/air/asbestos/index.htm

World Health Organization Asbestos
This is the executive summary of a report prepared by the World Health Organization on the human health risks of exposure to asbestos fibers.
http://www.asbestos-institute.ca/reviews/oxford.html#0

EPA Region 9 Air Quality
Read about air quality trends in EPA Region 9 (AZ, CA, HW, NV).
http://www.epa.gov/region09/air/breath96/exec.html
Additional information about air quality programs and current issues in Region 9 can be found at the following site.
http://www.epa.gov/region09/air/

Mexico City Air Pollution
This is a discussion of automobile usage in Mexico City.
http://www.colby.edu/personal/thtieten/air-mex.html

Environment Canada Air Quality
This web site provides a summary of air quality information for Canada.
http://www.mb.ec.gc.ca/air/a00s18.en.html

South Coast Air Quality Management District
A number of air pollution web sites are linked here. Most deal with southern California, Mexico, and Texas.
http://www.aqmd.gov/otherlnk.html

Clean Air and Energy, National Resources Defense Council
From here, view information on particulate air pollution, the Clean Air Act, and any pending legislation related to it, air pollution and children's health, and urban air pollution problems.
http://www.nrdc.org/air/

U.S. Environmental Protection Agency Office of Air and Radiation
This site offers an abundance of great current information and data on urban air pollution, acid rain, air toxics, and more. Browse their publications covering acid rain and emission trends for NOx, SOx, CO2, O3, and others.
http://www.epa.gov/oar/oarhome.html