1274 Meteorological Effects on Nitryl Chloride in an Urban Wintertime Environment

Wednesday, 15 January 2020
Hall B (Boston Convention and Exhibition Center)
Kathryn D. Kulju, Univ. of Michigan, Ann Arbor, MI; and S. M. McNamara, Q. Chen, J. Edebeli, J. D. Fuentes, S. B. Bertman, and K. A. Pratt

The photolysis of atmospheric nitryl chloride (ClNO2) produces chlorine radicals and nitrogen dioxide (NO2), which alter pollutant fates and air quality. ClNO2 is formed at night from the reaction of dinitrogen pentoxide (N2O5) on chloride-containing aerosols. Both ClNO2 and N2O5 are important nocturnal reservoir species for nitrogen oxides (NOx = NO + NO2), an EPA-regulated pollutant ubiquitous in urban environments that drives the production tropospheric ozone (O3). Meteorological parameters influence the abundance of ClNO2 and N2O5, as well as their precursors, including NOx, O3, and particulate chloride. However, the effects of meteorology on ClNO2 production are not yet well understood, as most observational and modeling studies focus on periods of clear air. During a field campaign in Kalamazoo, Michigan from Jan - Feb 2018, N2O5 and ClNO2 were measured using chemical ionization mass spectrometry (CIMS), with simultaneous measurements of atmospheric particulate matter and meteorology. We examine the impacts of atmospheric turbulence, precipitation (rain, snow, and fog), and ground cover (snow covered vs. bare ground) on the abundances of ClNO2 and N2O5. These observations aid our understanding of chlorine chemistry under conditions that are not ideal for atmospheric modeling.
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