Secondary Organic Aerosol Formation in the Southeastern United States

该项目将研究乔治亚州亚特兰大市人为和生物挥发性有机化合物（VOCs）产生的轻质氧化产物作为二次有机气溶胶（SOA）的来源。SOA形成的机制包括低碳数、水溶性、次生VOCs向颗粒水相的分配，在水相中它们被非均质氧化成低蒸汽压的产物。为了研究这一过程，首席研究员（PI）建议对气体和气溶胶相中的一组小型有机酸和羰基化合物进行在线测量，并进行额外的辅助测量。这些实验将在不同的地点进行一段较长的时间，以检查影响气-颗粒分配及其与亲水/疏水馏分和整体颗粒水溶性有机碳质量的联系的因素。该项目的动机是在城市大气中观察到意想不到的高SOA浓度，这无法用当前的SOA形成化学机制来解释。

This project will investigate lightweight oxidation products from anthropogenic and biogenic volatile organic compounds (VOCs) as a source for secondary organic aerosol (SOA) in urban Atlanta, Georgia. The mechanism through which SOA may be formed involves partitioning of low carbon-number, water-soluble, secondary VOCs to the particle aqueous phase where they are heterogeneously oxidized to lower vapor pressure products. To investigate this process the Principal Investigator (PI) proposes to undertake online measurements of a suite of small organic acid and carbonyl compounds in the gas and aerosol phases, along with additional ancillary measurements. These experiments will be conducted over an extended period of time at a variety of sites to examine factors that influence the gas-particle partitioning and its linkage to hydrophilic/hydrophobic fractions and overall particle water-soluble organic carbon mass. The motivation for the project is the unexpectedly high SOA concentrations observed in urban atmospheres that cannot be explained by current SOA formation chemical mechanisms.