2. http://www.epa.gov/oar/
3. http://airnow.gov/
4. http://www.nlm.nih.gov/medlineplus/airpollution.html
5. http://www.cdc.gov/nceh/airpollution/
6. http://www.epa.gov/iaq/
7. http://www.cdphe.state.co.us/ap/index.html
8. http://www.baaqmd.gov/
9. http://www.law.cornell.edu/uscode/html/uscode42/usc_sup_01_42_10_85.html
10. http://www.ecy.wa.gov/programs/air/airhome.html
11. http://www.cabq.gov/airquality/
12. http://www.nasa.gov/vision/earth/environment/brown_cloud.html
13. http://www.atsdr.cdc.gov/general/theair.html
14. http://www.earth911.org
15.http://www.greenpeace.org
2.U.S. Enviromental Protection Agency, 2006
3.AirNow, 2006
4. Medline Plus, 2006
5. Centers for Disease Control and Prevention, 2006
6.U.S. Environmental Protection Agency, 2006
7. Colorado Department of Public Health and Environment, 2006
8.Lynn Miller, 2006
9. Cornell Law School, 2006
10.Washington State Department of Ecology, 2006
11. City of Albuquerque, 2006
12. Rob Gutro, 2004
13. ATSDR
14.Blobal Security Alerts, LLC, 2006
15.Greenpeace, 2006