Fine particle residential indoor air pollution

Abstract

Indoor-generated elemental constituents of fine aerosol particulate matter may be distinguished from constituents infiltrating from the outdoors by comparing time variation in concentrations on an hourly basis. Measurements within three residential buildings indicate that sulfur and lead-bromine aerosols are predominantly of outdoor origin, although a secondary indoor lead source was detected. Potassium is, to a significant degree, of indoor origin. Indoor-outdoor exchange times inferred for fine particle constituents are in agreement with those estimated for gas exchange and with model calculations, suggesting conservative fine aerosol transport. However, coarse particle constituents e.g., iron, exhibit time variability complicated by nonconservative behavior, such as removal by filtration and settling. The experimental techniques used in this study, time sequence filter sampling of aerosols and elemental analysis by PIXE, are generally applicable to studies of the indoor working, as well as living, environments.