Sources and physical characteristics of atmospheric carbonaceous aerosols

In this thesis the sources and the ambient physical characteristics of atmospheric carbonaceous aerosols are identified for the Pittsburgh region. The analysis is performed as a combination of intensive field sampling campaigns and the application of different aerosol modeling efforts.; In the first section, an emissions inventory is developed to identify the main sources of organic and elemental carbon in the area and estimate the contributions of primary and secondary OC in the region. In the second section, a method (EC tracer) is developed to estimate the contributions of primary and secondary OC from data collected at the Pittsburgh Air Quality Study (PAQS). Reasonable agreement on the contribution of primary and secondary OC is obtained from the inventory approach and the application of the EC tracer method for the different seasons.; The physical characteristics of carbonaceous and other aerosols are determined from ambient size distribution data. Inferences about the sources and the physicochemical transformations of atmospheric aerosols in the Eastern US are established. Seasonal patterns for several size cuts are reported.; Finally, the optical properties of the aerosols are estimated from several approaches. The main causes of visibility degradation are identified and novel methods to estimate visibility impairment are introduced.