Is oxidation of atmospheric mercury controlled by different mechanisms in the polluted continental boundary layer vs. remote marine boundary layer?

Maor Gabay, Shira Raveh-Rubin, Mordechai Peleg, Erick Fredj, Eran Tas

Research output: Contribution to journalArticlepeer-review

5 Scopus citations

Abstract

Deposition of atmospheric mercury is of global concern, primarily due to health effects associated with efficient bioaccumulation of mercury in marine food webs. Although oxidation of gaseous elementary mercury (GEM), the major fraction of atmospheric mercury, is a critical stage in regulating atmospheric mercury deposition efficiency, this oxidation is currently not well-characterized, limiting modeling-based assessments of mercury in the environment. Based on a previous study, we hypothesized that the oxidation of GEM is predominantly controlled by multistep bromine- A nd chlorine-induced oxidation (MBCO) in the remote marine boundary layer (RMBL), and by photochemical smog oxidants, primarily ozone (O3) and hydroxyl radical (OH), in the polluted continental boundary layer (PCBL). To test this hypothesis, we used the following analyses: (i) application of a newly developed criterion to evaluate the gaseous oxidized mercury (GOM)-O3 association based on previous studies in the RMBL and PCBL; (ii) measurement-based box simulations of GEM oxidation in the RMBL and at a PCBL site; and (iii) measurement-based analysis of photochemical oxidation vs. other processes which potentially influence GOM. Our model simulations indicated that the MBCO mechanism can reproduce GOM levels in the RMBL, but not in the PCBL. Our data analysis suggested the important role of photochemical smog oxidants in GEM oxidation in the PCBL, potentially masked by the effect of relative humidity and entrainment of free tropospheric air.

Original languageAmerican English
Article number064026
JournalEnvironmental Research Letters
Volume15
Issue number6
DOIs
StatePublished - Jun 2020

Bibliographical note

Publisher Copyright:
© 2020 The Author(s). Published by IOP Publishing Ltd.

Keywords

  • Atmospheric mercury oxidation
  • GEM
  • GOM
  • field measurements
  • hydroxyl radical
  • ozone
  • photochemistry

Fingerprint

Dive into the research topics of 'Is oxidation of atmospheric mercury controlled by different mechanisms in the polluted continental boundary layer vs. remote marine boundary layer?'. Together they form a unique fingerprint.

Cite this