Evidence against Rapid Mercury Oxidation in Photochemical Smog

Mercury pollution is primarily emitted to the atmosphere, and atmospheric transport and chemical processes determine its fate in the environment, but scientific understanding of atmospheric mercury chemistry is clouded in uncertainty. Mercury oxidation by atomic bromine in the Arctic and the upper atmosphere is well established, but less is understood about oxidation pathways in conditions of anthropogenic photochemical smog. Many have observed rapid increases in oxidized mercury under polluted conditions, but it has not been clearly demonstrated that these increases are the result of local mercury oxidation. We measured elemental and oxidized mercury in an area that experienced abundant photochemical activity (ozone >100 ppb) during winter inversion (i.e., cold air pools) conditions that restricted entrainment of air from the oxidized mercury-rich upper atmosphere. Under these conditions, oxidized mercury concentrations decreased day-upon-day, even as ozone and other pollutants increased dramatically. A box model that incorporated rapid kinetics for reactions of elemental mercury with ozone and OH radical overestimated observed oxidized mercury, while incorporation of slower, more widely accepted reaction rates did not. Our results show that rapid gas-phase mercury oxidation by ozone and OH in photochemical smog is unlikely.

Medienart:

E-Artikel

Erscheinungsjahr:

2022

Erschienen:

2022

Enthalten in:

Zur Gesamtaufnahme - volume:56

Enthalten in:

Environmental science & technology - 56(2022), 16 vom: 16. Aug., Seite 11225-11235

Sprache:

Englisch

Beteiligte Personen:

Lyman, Seth N [VerfasserIn]
Elgiar, Tyler [VerfasserIn]
Gustin, Mae Sexauer [VerfasserIn]
Dunham-Cheatham, Sarrah M [VerfasserIn]
David, Liji M [VerfasserIn]
Zhang, Lei [VerfasserIn]

Links:

Volltext

Themen:

66H7ZZK23N
Air Pollutants
Chemical mechanism
FXS1BY2PGL
Journal Article
Mercury
Model
Oxidation
Ozone
Research Support, Non-U.S. Gov't
Smog

Anmerkungen:

Date Completed 17.08.2022

Date Revised 26.08.2022

published: Print-Electronic

Citation Status MEDLINE

doi:

10.1021/acs.est.2c02224

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM343972794