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

该项目的重点是更好地了解控制大气中细颗粒物浓度和组成的时空变化的因素，特别强调有机气溶胶的可变性。大气中细颗粒物的空间变异性部分源于排放源的时空趋势，这些排放物随后与背景空气的混合，以及排放物的物理和化学处理。研究的具体目标是：(1)通过对交通、背景气溶胶和工业排放有显著贡献的区域的一系列环境测量，确定大气细颗粒物成分的时空变异性；(2)将这种变异性与源和化学处理的时空变异性联系起来，目的是以高保真度和特异度确定来源对OA的贡献；以及(3)更好地了解物理(如蒸发)和化学(如氧化)转化如何在相关的空间和时间尺度(几秒到几天，约10米-100公里)上影响环境中挥发性有机化合物的浓度和组成。该项目将侧重于一系列案例研究(工业为主、交通为主、城乡样带)，以调查OA的排放和随后的物理化学处理，并使用因子分析和聚类分析工具来确定OA的来源，并探索其化学演化。宾夕法尼亚州匹兹堡的采样网络由一个固定的采样点组成，周围将部署一个流动实验室来表征空间变化。

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.