Photochemical Modeling of Wintertime HOx Sources and Sinks in a Subarctic Urban Location
8 affiliations
- 1Institute for Climate and Atmospheric Science, School of Earth & Environment , , ,
- 2School of Chemistry , , ,
- 3UCLA Atmospheric & Oceanic Sciences , , ,
- 4Aix-Marseille Université, CNRS, LCE , ,
- 5LATMOS/IPSL , , ,
- 6Earth & Atmospheric Sciences , University of Houston , , ,
- 7GESTAR-II , University of Maryland Baltimore County , , ,
- 8Geophysical Institute and Department of Chemistry and Biochemistry , , , ,
Abstract
The hydroxyl radical (OH) is a key atmospheric oxidant that is important for regulating pollutant concentrations and particle formation and composition. The globally dominant formation mechanism of OH is ozone photolysis. However, the low-light conditions in the wintertime Arctic may limit OH formation through this pathway, and there is a lack of observations available to explain oxidant chemistry in polar locations. We use the Dynamically Simple Model of Atmospheric Chemical Complexity (DSMACC) 0D model to assess processes controlling the abundances of atmospheric oxidants in a subarctic city. To constrain the model, we use measurements made during the Alaskan Layered Pollution and Chemical Analysis (ALPACA) field campaign, which took place in Fairbanks, Alaska, USA, during the winter of 2022. HONO photolysis to form OH is the major chemical source of HO x in the polluted, low-light environment of wintertime Fairbanks, and formaldehyde is an important precursor for HO 2 . We find that the HO x budget is distinct between a polluted, strongly stable inversion event and a clean, weakly stable period because of the different meteorology and pollution levels regulating peroxynitric acid (PNA, HO 2 NO 2 ) cycling. Our results improve our understanding of the unique atmospheric pollution chemistry under cold and low-light conditions.
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BibTeX
@article{hoffman2026photochemical,
title = {{Photochemical Modeling of Wintertime HOx Sources and Sinks in a Subarctic Urban Location}},
author = {Alicia Hoffman and Rachel L. James and Dwayne E. Heard and Lisa Whalley and Daniel Stone and Samuel Seldon and Jochen Stutz and Jonas Kuhn and Sol Cooperdock and Brice Temime-Roussel and Amna Ijaz and Barbara D’Anna and Kathy S. Law and Slimane Bekki and Fangzhou Guo and James Flynn and James M. St Clair and Meeta Cesler-Maloney and William R. Simpson and Steve R. Arnold},
journal = {ACS ES\&T air},
year = {2026},
month = sep,
doi = {10.1021/acsestair.6c00254},
url = {https://europepmc.org/article/PMC/PMC13660409},
note = {CC BY},
}
RIS
TY - JOUR
TI - Photochemical Modeling of Wintertime HOx Sources and Sinks in a Subarctic Urban Location
AU - Alicia Hoffman
AU - Rachel L. James
AU - Dwayne E. Heard
AU - Lisa Whalley
AU - Daniel Stone
AU - Samuel Seldon
AU - Jochen Stutz
AU - Jonas Kuhn
AU - Sol Cooperdock
AU - Brice Temime-Roussel
AU - Amna Ijaz
AU - Barbara D’Anna
AU - Kathy S. Law
AU - Slimane Bekki
AU - Fangzhou Guo
AU - James Flynn
AU - James M. St Clair
AU - Meeta Cesler-Maloney
AU - William R. Simpson
AU - Steve R. Arnold
PY - 2026
DA - 2026/09/12
JO - ACS ES&T air
DO - 10.1021/acsestair.6c00254
UR - https://europepmc.org/article/PMC/PMC13660409
AB - The hydroxyl radical (OH) is a key atmospheric oxidant that is important for regulating pollutant concentrations and particle formation and composition. The globally dominant formation mechanism of OH is ozone photolysis. However, the low-light conditions in the wintertime Arctic may limit OH formation through this pathway, and there is a lack of observations available to explain oxidant chemistry in polar locations. We use the Dynamically Simple Model of Atmospheric Chemical Complexity (DSMACC) 0D model to assess processes controlling the abundances of atmospheric oxidants in a subarctic city. To constrain the model, we use measurements made during the Alaskan Layered Pollution and Chemical Analysis (ALPACA) field campaign, which took place in Fairbanks, Alaska, USA, during the winter of 2022. HONO photolysis to form OH is the major chemical source of HO x in the polluted, low-light environment of wintertime Fairbanks, and formaldehyde is an important precursor for HO 2 . We find that the HO x budget is distinct between a polluted, strongly stable inversion event and a clean, weakly stable period because of the different meteorology and pollution levels regulating peroxynitric acid (PNA, HO 2 NO 2 ) cycling. Our results improve our understanding of the unique atmospheric pollution chemistry under cold and low-light conditions.
SN - 2837-1402
ER -