Effects of modified residential construction on indoor air quality

Indoor air quality (IAQ) was assessed in homes in an experimental community of single-family dwellings that had been built with materials chosen for low pollutant emission and other modified design features to provide enhanced residential indoor air quality. The IAQ was measured in six of these experimental homes and also tit three conventionally built homes of similar size and price range. The IAQ was assessed shortly after construction before the houses were occupied and again after each of the houses had been occupied for five months. Before occupancy, there were higher levels of airborne particles and of some volatile organic compounds in the conventional homes than in the experimental homes. During occupancy, benzene, ethylbenzene, m- and p-xylene, and o-xylene were all higher in the conventional homes, but dichloromethane, Freon 11, and trichlorethylene were higher in the experimental homes. In the conventional homes, mean level of benzene and chloroform increased, whereas methylchloroform and toluene levels decreased from preoccupancy to occupancy. In the experimental homes, dichloromethane increased, and m- and p-xylene and o-xylene decreased from preoccupancy to occupancy. The results suggest that attached garages, geographical siting, and occupants' activities substantially influenced the IAQ in these homes. The enhanced indoor air quality homes tested in this study were judged to be at least partially effective, with the most obvious sustained IAQ benefits being related to the lack of an attached garage.