Collaborative Research: Aerosol Formation from Agricultural Volatile Organic Compounds

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This project is investigating the potential for agricultural emissions of nitrogen and sulfur gases from sources such as dairy farms, piggeries, and other animal production sources to lead to the formation of very small particles in the atmosphere. Previous studies have shown that gas phase compounds related to waste management practices from animal agriculture could influence the formation of atmospheric particles. This project includes laboratory, field and modeling studies to investigate the environmental fate of nitrogen and sulfur compounds from these sources. An environmental chamber will be used to quantify secondary aerosol formation potentials at different relative humidities and temperatures for select amines (diethylamine (DEA), trimethylamine (TMA), butylamine (BA), a diamine, or NH3) oxidized in the presence of an organosulfur compound (methanethiol, dimethylsulfide (DMS), or dimethyldisulfide (DMDS)) or hydrogen sulfide. The investigators will perform field sampling of particulate matter and precursors at agricultural operations in Kentucky at the USDA-Agricultural Research Station (ARS) laboratory to determine the impact of elevated amine and sulfur concentrations on atmospheric chemistry.Kinetic modeling calculations will help clarify the sequence of chemical reactions responsible for the data seen in laboratory experiments. This will, in turn, help explain emission rates observed in field observations. The investigators expect to elucidate the atmospheric oxidation routes for reduced sulfur compounds and amines. Empirical estimates of the aerosol formation potential of key agricultural emissions will be developed for use in predicting local and regional air quality impacts and emissions inventories of the reduced nitrogen and sulfur species will be developed as an additional input to air quality models.