Clean Air Delivery Rate
Explains this rating system for air cleaners and shows application examples. Also provides a tutorial about air cleaners.
http://www.cadr.org/

Healthy Home and Workplace Pty. Ltd.
Information about health issues relating to indoor living and working environments as well as safe housing and associated technologies.
http://www.healthyhouse.com/

Indoor Environment Connections
Offers information about a trade magazine for commercial, industrial, and institutional building owners providing data about indoor environmental issues.
http://www.ieconnections.com/

Airpak
Offers software for modeling air flow, thermal transfer, and contaminant distribution in ventilation systems and other indoor environments. Includes online demonstration, contact information, and sample output.
http://airpak.fluent.com/