Collaborative Research: Aerosol Formation from Agricultural Volatile Organic Compounds

该项目正在调查农业排放氮和硫气体的可能性，这些气体来自奶牛场、养猪场和其他动物生产来源，导致大气中形成非常小的颗粒。先前的研究表明，与畜牧业废物管理实践有关的气相化合物可能影响大气颗粒的形成。该项目包括实验室、实地和模型研究，以调查来自这些来源的氮和硫化合物的环境命运。环境室将用于量化在不同相对湿度和温度下，某些胺（二乙胺（DEA）、三甲胺（TMA）、丁胺（BA）、二胺或NH3）在有机硫化合物（甲硫醇、二甲硫化物（DMS）或二甲二硫化物（DMDS））或硫化氢存在下氧化的二次气溶胶形成电位。研究人员将在美国农业部农业研究站（ARS）实验室对肯塔基州农业作业中的微粒物质和前体进行实地取样，以确定胺和硫浓度升高对大气化学的影响。动力学模型计算将有助于澄清化学反应的顺序，这些化学反应负责实验室实验中看到的数据。这反过来将有助于解释在实地观测中观测到的排放率。研究人员希望阐明还原硫化合物和胺的大气氧化途径。将开发主要农业排放的气溶胶形成潜力的经验估计，用于预测当地和区域空气质量影响，并将开发减少的氮和硫物种的排放清单，作为空气质量模型的额外输入。

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.