House-specific characterization of indoor and outdoor aerosols.

Simultaneous air monitoring inside and outside of 12 homes in the Houston area were performed for fine inhalable particulate matter by means of dichotomous samplers. The patterns of house-specific indoor mean concentrations, indoor/outdoor ratios, and probable source of indoor fine aerosol are discussed, along with pertinent information on household characteristics. The results suggest that most of indoor aerosol appears to be affected by infiltration of outdoor air as well as by indoor generation, with the most important single determinant being the presence or absence of cigarette smoking. However, it is likely that the typical complexity of indoor environments make it difficult to explain sources of indoor aerosol.