@article{2a16528297bc46449de524f4e2558ff4,
title = "Observation of Road Salt Aerosol Driving Inland Wintertime Atmospheric Chlorine Chemistry",
abstract = "Inland sources of particulate chloride for atmospheric nitryl chloride (ClNO2) formation remain unknown and unquantified, hindering air quality assessments. Globally each winter, tens of millions of tons of road salt are spread on roadways for deicing. Here, we identify road salt aerosol as the primary chloride aerosol source, accounting for 80-100% of ClNO2 formation, at an inland urban area in the wintertime. This study provides experimental evidence of the connection between road salt and air quality through the production of this important reservoir for nitrogen oxides and chlorine radicals, which significantly impact atmospheric composition and pollutant fates. A numerical model was employed to quantify the contributions of chloride sources to ClNO2 production. The traditional method for simulating ClNO2 considers chloride to be homogeneously distributed across the atmospheric particle population; yet, we show that only a fraction of the particulate surface area contains chloride. Our new single-particle parametrization considers this heterogeneity, dramatically lowering overestimations of ClNO2 levels that have been routinely reported using the prevailing methods. The identification of road salt as a ClNO2 source links this common deicing practice to atmospheric composition and air quality in the urban wintertime environment.",
author = "Mcnamara, {Stephen M.} and Kolesar, {Katheryn R.} and Siyuan Wang and Kirpes, {Rachel M.} and May, {Nathaniel W.} and Gunsch, {Matthew J.} and Cook, {Ryan D.} and Fuentes, {Jose D.} and Hornbrook, {Rebecca S.} and Apel, {Eric C.} and Swarup China and Alexander Laskin and Pratt, {Kerri A.}",
note = "Funding Information: Funding was provided by the University of Michigan (UM), an Alfred P. Sloan Foundation Research Fellowship in Chemistry (FG-2017-9431), and the National Science Foundation (NSF) Atmospheric Chemistry program (AGS-1738588). K.R.K. was partially funded by a Dow Postdoctoral Fellowship in Sustainability from UM. S.M.M. and N.W.M. were partially funded by U.S. Department of Education Graduate Assistance in Areas of National Need fellowships. CCSEM-EDX analyses were performed at the Environmental Molecular Sciences Laboratory, a national scientific user facility located at the Pacific Northwest National Laboratory and sponsored by the Office of Biological and Environmental Research of the U.S. Department of Energy. Additional CCSEM-EDX analyses were conducted at the Michigan Center for Materials Characterization, which is thanked for use of the instruments and staff assistance. The National Center for Atmospheric Research is sponsored by the NSF; 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 NSF. The authors thank D. J. Tanner and L. G. Huey (Georgia Institute of Technology) for providing the NO analyzer, T. B. Ryerson (National Oceanic and Atmospheric Administration) for providing the photolytic NO converter, C. Mattson, A. Barget, A. Kevelin, M. Morales, M. Parks, G. Verwer, and A. Leemon (UM) for experimental assistance, C. R. Thompson (NOAA) for assistance with NO measurements and helpful discussions, and A. P. Ault, P. K. Peterson (UM), and H. Osthoff (University of Calgary) for helpful discussions. 2 x Publisher Copyright: {\textcopyright} 2020 American Chemical Society.",
year = "2020",
month = may,
day = "27",
doi = "10.1021/acscentsci.9b00994",
language = "English (US)",
volume = "6",
pages = "684--694",
journal = "ACS Central Science",
issn = "2374-7943",
publisher = "American Chemical Society",
number = "5",
}