Spatial Variability in Organic Aerosol: Relationships between Sources, Processing, and Composition

Carnegie Mellon University, Pittsburgh PA

Investigators

Abstract

This project focuses on developing a better understanding of the factors governing spatial and temporal variations in fine particle concentration and composition in the atmosphere, with specific emphasis on variability in organic aerosol (OA). Spatial variability of fine particles in the atmosphere derives in part from spatial-temporal trends in emissions sources, the subsequent mixing of these emissions with background air, and the physical and chemical processing of the emissions. The specific objectives of the research are: (1) Determine spatial-temporal variability in OA composition through a series of ambient measurements in a region with significant contributions from traffic, background aerosol, and industrial emissions; (2) Relate this variability to spatial and temporal variability in sources and chemical processing, with the goal of identifying source contributions to OA with high fidelity and specificity; and (3) Develop an improved understanding of how physical (e.g., evaporation) and chemical (e.g., oxidation) transformations affect ambient OA concentrations and composition over relevant spatial and temporal scales (seconds to days, ~10 m - 100 km). The project will focus on a series of case studies (industrial-dominated, traffic-dominated, urban-rural transect) to investigate OA emissions and subsequent physical and chemical processing, and use factor analysis and cluster analysis tools to determine OA sources and to probe its chemical evolution. The sampling network in Pittsburgh PA consists of a stationary sampling site, around which a mobile laboratory will be deployed to characterize spatial variations.