What's in the air for tightly built houses?

Reviews literature on the health effects of indoor air pollutants in energy-efficient homes with low ventilation rates. Discusses hazards from gas cooking, formaldehyde, radon and other pollutants. Suggests air infiltration rate of 0.5 air changes/hour to keep indoor pollution to below critical levles. Also suggests installation of an air-to-air heat exchanger or electronic air cleaner.