TY - JOUR
T1 - Urban Snowpack ClNO2Production and Fate
T2 - A One-Dimensional Modeling Study
AU - Wang, Siyuan
AU - McNamara, Stephen M.
AU - Kolesar, Katheryn R.
AU - May, Nathaniel W.
AU - Fuentes, Jose D.
AU - Cook, Ryan D.
AU - Gunsch, Matthew J.
AU - Mattson, Claire N.
AU - Hornbrook, Rebecca S.
AU - Apel, Eric C.
AU - Pratt, Kerri A.
N1 - Funding Information:
Funding was provided by the University of Michigan and the National Science Foundation Atmospheric Chemistry program (AGS-1738588). K.R.K. was partially funded by a Dow Postdoctoral Fellowship in Sustainability from the University of Michigan. S.M.M. and N.W.M. were partially funded by U.S. Department of Education Graduate Assistance in Areas of National Need (GAANN) fellowships. The authors thank David J. Tanner and L. Gregory Huey (Georgia Institute of Technology) for providing the NO analyzer, Thomas B. Ryerson and Chelsea R. Thompson (NOAA) for providing the photolytic NO converter, Alicia Kevelin, Madeline Parks, and Maria Morales (University of Michigan) for snow sampling and IC analysis, and Chelsea R. Thompson (NOAA) for assistance with NO measurements and helpful discussions. The National Center for Atmospheric Research is sponsored by the National Science Foundation; any opinions, findings, and conclusions or recommendations expressed in this publication are those of the authors and do not necessarily reflect the views of the National Science Foundation. The authors thank the reviewers for their comments that improved the manuscript and the editor for expeditiously handling the manuscript, especially given the current global challenges. 2 x
Publisher Copyright:
© 2020 American Chemical Society.
PY - 2020/7/16
Y1 - 2020/7/16
N2 - Nitryl chloride (ClNO2) is formed in urban areas from the multiphase reaction of dinitrogen pentoxide (N2O5) on chloride-containing surfaces. ClNO2 undergoes photolysis to produce atomic chlorine (Cl•), a strong atmospheric oxidant. While previous ClNO2 studies have focused on atmospheric particulate chloride, the saline snowpack in locations impacted by sea spray and road salt usage represents an additional, potentially large, source of ClNO2. Here, we present the first modeling study to explore the production of ClNO2 from the inland urban snowpack. The coupled snowpack-atmospheric one-dimensional model is constrained to and evaluated by an array of ambient measurements in Ann Arbor, Michigan, during February 2016. The model predicts strong N2O5 deposition onto the snowpack, with ClNO2 formation and release to the atmosphere at low temperatures (<∼260 K). However, at higher temperatures (>∼270 K), the ClNO2 yield is low (e.g., 10%), with ClNO2 undergoing hydrolysis on the snow grains, making the snowpack a net sink for ClNO2. These results motivate measurements to quantify ClNO2 production from the urban snowpack because of potential broader impacts on atmospheric composition and air quality.
AB - Nitryl chloride (ClNO2) is formed in urban areas from the multiphase reaction of dinitrogen pentoxide (N2O5) on chloride-containing surfaces. ClNO2 undergoes photolysis to produce atomic chlorine (Cl•), a strong atmospheric oxidant. While previous ClNO2 studies have focused on atmospheric particulate chloride, the saline snowpack in locations impacted by sea spray and road salt usage represents an additional, potentially large, source of ClNO2. Here, we present the first modeling study to explore the production of ClNO2 from the inland urban snowpack. The coupled snowpack-atmospheric one-dimensional model is constrained to and evaluated by an array of ambient measurements in Ann Arbor, Michigan, during February 2016. The model predicts strong N2O5 deposition onto the snowpack, with ClNO2 formation and release to the atmosphere at low temperatures (<∼260 K). However, at higher temperatures (>∼270 K), the ClNO2 yield is low (e.g., 10%), with ClNO2 undergoing hydrolysis on the snow grains, making the snowpack a net sink for ClNO2. These results motivate measurements to quantify ClNO2 production from the urban snowpack because of potential broader impacts on atmospheric composition and air quality.
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U2 - 10.1021/acsearthspacechem.0c00116
DO - 10.1021/acsearthspacechem.0c00116
M3 - Article
AN - SCOPUS:85088869875
SN - 2472-3452
VL - 4
SP - 1140
EP - 1148
JO - ACS Earth and Space Chemistry
JF - ACS Earth and Space Chemistry
IS - 7
ER -