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  • Urban inland wintertime N<sub>2</sub>O<sub>5</sub> and ClNO<sub>2</sub> influenced by snow-covered ground, air turbulence, and precipitation
Title: Urban inland wintertime N<sub>2</sub>O<sub>5</sub> and ClNO<sub>2</sub> influenced by snow-covered ground, air turbulence, and precipitation
Abstract. The atmospheric multiphase reaction of dinitrogenpentoxide (N2O5) with chloride-containing aerosol particlesproduces nitryl chloride (ClNO2), which has been observed across theglobe. The photolysis of ClNO2 produces chlorine radicals and nitrogendioxide (NO2), which alter pollutant fates and air quality. However,the effects of local meteorology on near-surface ClNO2 production arenot yet well understood, as most observational and modeling studies focus onperiods of clear conditions. During a field campaign in Kalamazoo, Michigan,from January–February 2018, N2O5 and ClNO2 were measuredusing chemical ionization mass spectrometry, with simultaneous measurementsof atmospheric particulate matter and meteorological parameters. We examinethe impacts of atmospheric turbulence, precipitation (snow, rain) and fog,and ground cover (snow-covered and bare ground) on the abundances ofClNO2 and N2O5. N2O5 mole ratios were lowest duringperiods of lower turbulence and were not statistically significantlydifferent between snow-covered and bare ground. In contrast, ClNO2 moleratios were highest, on average, over snow-covered ground, due to salinesnowpack ClNO2 production. Both N2O5 and ClNO2 moleratios were lowest, on average, during rainfall and fog because ofscavenging, with N2O5 scavenging by fog droplets likelycontributing to observed increased particulate nitrate concentrations. Theseobservations, specifically those during active precipitation and withsnow-covered ground, highlight important processes, including N2O5and ClNO2 wet scavenging, fog nitrate production, and snowpackClNO2 production, that govern the variability in observed atmosphericchlorine and nitrogen chemistry and are missed when considering only clearconditions.  more » « less
Award ID(s):
1738588
PAR ID:
10323458
Author(s) / Creator(s):
; ; ; ; ; ; ;
Date Published:
Journal Name:
Atmospheric Chemistry and Physics
Volume:
22
Issue:
4
ISSN:
1680-7324
Page Range / eLocation ID:
2553 to 2568
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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