| Airborne particulate matter (PM) concentrations are impacted by neighborhood, urban and regional-scale sources of organic PM emitted directly (primary) and formed in the atmosphere (secondary). Indoor organic PM is influenced by both indoor and outdoor contributions. This dissertation furthers the understanding of all these sources. The polarity of organic PM (a property important to visibility degradation, direct and indirect climate forcing, and human health) was also studied.; Examination of the particle concentration dynamics in Pittsburgh, PA, suggested that multi-day formation and regional transport is an important contributor to particulate organic carbon (OC) in locations that are recipients of long distance transport, e.g. the eastern U.S. Very polar compounds dominated the organic aerosol at this location, and the annual average organic molecular weight-per-carbon weight (OM/OC) was 1.91 +/- 0.24 (1sigma). The contribution of non-extractable organics could increase this ratio as high as 2.05 +/- 0.18 (1sigma). OM/OC varied little across the year and is consistent with measurements in similar locations across the globe.; Outside residences, urban and neighborhood scale sources add to the regional aerosol. Multiple linear regression analysis of data from the Relationship of Indoor, Outdoor, and Personal Air (RIOPA) study suggested that proximity to local sources had a modest effect on PM2.5 mass (concentration at homes located within 37 m from interstate roadways was 24.0 mug/m 3, about 9 mug/m3 higher than the background concentration 250 m away). In some cases the elevation of PAHs and EC concentrations was substantial outside homes closest to sources (i.e., ∼ 20 times for PAHs with interstate roadways, and ∼ 14 times for EC with the oil refinery located in Linden, NJ). Organic material was the predominant species in indoor-generated PM2.5, based analysis of RIOPA data. The emission or production of particulate organic compounds indoors (∼75% of measured indoor OC) was substantial enough to alter the concentration, composition and behavior of indoor PM2.5.; A better understanding of the relative contributions of primary, secondary, urban, regional, neighborhood and indoor sources to organic PM exposure will help to design effective air quality control strategies and to guide regulatory decision-making for public health protection. |
