10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
Abstract View
Formation and Growth of Aerosol from Agricultural Emissions
PHILIP SILVA, USDA - Agricultural Research Service
Abstract Number: 83 Working Group: Aerosol Chemistry
Abstract Particulate matter influences on the environment from agriculture are usually considered to be dominantly coarse mode dust with some secondary component in the fine mode from the impact of ammonia emission. Indeed, some scientists have started investigating whether and how ammonia can interact with anthropogenic and biogenic hydrocarbons to form secondary aerosol. But agricultural emissions include many reactive volatile organic compounds that may potentially contribute to secondary aerosols with or without ammonia. We have performed several field sampling experiments at a poultry house, a dairy, and a hog farm to find evidence for secondary aerosol formation, including new particle formation at the source. We use a scanning mobility particle sizer (SMPS) to acquire size distributions of particles from 10 nm – 0.5 μm in 5-min intervals. Data from the SMPS indicates that particle growth and particle formation events are observed at all facilities by the SMPS very near source. Some formation and growth events are rapid with particle growth exceeding 20 nm per hour. Some data for gas phase measurements of nitrogen- and sulfur-containing compounds will be discussed in terms of whether it is impacting the presence of particle formation or growth events. These data suggest that agricultural emissions may be underestimated as a source for new particulate matter in rural areas and that it is not just the interaction of ammonia with the urban plume that produces secondary aerosol.