Radon and aldehyde concentrations in the indoor environment.

An energy-efficient residence in Mt. Airy, Maryland, USA, was monitored for aldehydes and radon in order to develop relationships between air infiltration rates and contaminant levels. One fifth of the measured formaldehyde concentrations were in the range that may cause health concerns. These concentrations were measured under very low air infiltration rates. Increased ventilation was effective in reducing high concentrations. Use of the heat exchanger led to an increase in the air infiltration rate which resulted in a substantial reduction of formaldehyde levels. Similar results were obtained for radon.