ABSTRACT
The airbourne toxic element and organic substance (ATEOS) study provided an extensive and unique set of aerosol composition measurements. This chapter aims to present the composition of inhalable particulate matter (IPM) at the four ATEOS sites in both absolute and relative terms, their intersite and seasonal variability, and relationships to the nature of the sources and meteorology at these sites. It discusses the major organic and inorganic components of IPM which are the extractable organic fractions, sulfate, resuspended soil, and certain trace element. Concentrations of ambient particulate matter, as well as its sulfate, organic, and lead components, were significantly lower at the urban ATEOS sites during the early 1980s than during the 1960s. Chemical composition can be equally significant with respect to the health impact of airborne particles. For example, sulfate aerosol, in the form of sulfuric acid, is more damaging to lung function than is ammonium sulfate.
