Understanding Sources of Atmospheric Hydrogen Chloride in Coastal Spring and Continental Winter

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review

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Author(s)

  • Andrea A. Angelucci
  • Teles C. Furlani
  • Daniel J. Jacob
  • Trevor C. VandenBoer
  • Cora J. Young

Related Research Unit(s)

Detail(s)

Original languageEnglish
Pages (from-to)2507-2516
Number of pages10
Journal / PublicationACS Earth and Space Chemistry
Volume5
Issue number9
Online published18 Aug 2021
Publication statusPublished - 16 Sept 2021

Abstract

Ambient 0.5 Hz hydrogen chloride (HCl) measurements were made in Canadian cities to investigate chlorine activation and constrain the tropospheric chlorine budget. Springtime HCl mixing ratios in a coastal city (St. John’s, NL) were up to 1200 parts per trillion by volume (pptv) with a median of 63 pptv and were consistently elevated during daytime. High time-resolution measurements allowed the attribution of events to general sources, including direct emissions. Most coastal HCl was related to sea-salt aerosol acid displacement (R1) and chlorine activation. Continental urban (Toronto, ON) wintertime HCl mixing ratios reached up to 541 and 172 pptv, with medians of 67 and 11 pptv during two sampling periods characterized by different wind directions. The absence of consistent relationships with NOx, temperature, and wind direction, as well as a lack of diurnal patterns, suggested uncharacterized direct sources of HCl. One period with road salting occurred during sampling, but no relationship to changes in HCl observations was found. The contribution of road salt to the measured HCl may have been masked by larger contributors (such as direct sources of HCl) or perhaps the relationship between HCl and road salt application is not immediate, and thus additional measurements over multiple salting events or between seasons would be required. GEOS-Chem modeled HCl temporal variations in mixing ratios agreed well with coastal measurements only. The measured mixing ratios were underestimated by the model in both locations, but to a greater degree (up to 3 orders of magnitude) in the continental city. The discrepancy between the model and measurements for the continental wintertime city emphasizes the need for a greater understanding of direct sources of HCl and the impact of road salt.

Research Area(s)

  • hydrogen chloride, reactive chlorine, cavity ring-down spectroscopy, GEOS-Chem, emissions, marine, continental, wintertime, road salt

Citation Format(s)

Understanding Sources of Atmospheric Hydrogen Chloride in Coastal Spring and Continental Winter. / Angelucci, Andrea A.; Furlani, Teles C.; Wang, Xuan et al.
In: ACS Earth and Space Chemistry, Vol. 5, No. 9, 16.09.2021, p. 2507-2516.

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review