NAFA

National Air Filtration Association

 http://nafahq.org/

ASHRAE

American Society of Heating, Refrigeration and Air Conditioning Engineers

 http://ashrae.org/

ARI

Air-Conditioning and Refrigeration Institute

 http://ari.org/

HARDI

Heating, Air Conditioning and Refrigeration Distributors International

 http://hardinet.org/

IAQ

Indoor Air Quality Association, Inc.

 http://iaqa.com/

EPA

United States Environmental Protection Agency

 http://epa.gov/iaq/