Comparisons of elements and inorganic compounds inside and outside of residences

The results of more than 1 yr of air monitoring inside and outside of five homes in each of two communities are presented for SO₂, NO₂, mass respirable particles, SO₄, Al, Br, Cl, Mn, Na, and V. Outdoor measurements across the home site in each city are consistent with proximity to outdoor sources. Looking across indoor residential sites in each city, the home appears to alter outdoor concentrations in several ways. Indoor level of SO₂, SO₄, Mn, and V are lower than those measured outdoors. These constituents are thought generally to result from outdoor sources. The other constituents studied are at times found in excess within homes. In some cases the source or sources of excess concentration of a particular constituent could be identified; often, however, the source of excess indoor concentration could not be identified.