Commission for Environmental Cooperation of North America
http://www.cec.org/home

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

AIR NOW-EPA
http://www.epa.gov/airnow/index.html

National Geographic Earthpulse
http://www.nationalgeographic.com/earthpulse/

MSNBC Environment Front
http://www.msnbc.com/news/environment_front.asp

American Lung Association
http://www.lungusa.org/air/

Kids

AIR NOW-EPA
http://www.epa.gov/airnow/aqikids/

EPA Explorers Club
http://www.epa.gov/kids/

World Wildlife Fund Kids
http://www.worldwildlife.org/fun/kids.cfm

Passport to Rainforest (NASA & NSF)
http://passporttoknowledge.com/rainforest/