Assessing the Oxidative Potential of Outdoor PM2.5 in Wintertime Fairbanks, Alaska

Yuhan Yang; Michael A Battaglia; Magesh Kumaran Mohan; Ellis S Robinson; Peter F DeCarlo; Kasey C Edwards; Ting Fang; Sukriti Kapur; Manabu Shiraiwa; Meeta Cesler-Maloney; William R Simpson; James R Campbell; Athanasios Nenes; Jingqiu Mao; Rodney J Weber

doi:10.1021/acsestair.3c00066

Assessing the Oxidative Potential of Outdoor PM_2.5 in Wintertime Fairbanks, Alaska

ACS EST Air. 2024 Feb 10;1(3):175-187. doi: 10.1021/acsestair.3c00066. eCollection 2024 Mar 8.

Authors

Yuhan Yang¹, Michael A Battaglia¹, Magesh Kumaran Mohan¹, Ellis S Robinson², Peter F DeCarlo², Kasey C Edwards³, Ting Fang³, Sukriti Kapur³, Manabu Shiraiwa³, Meeta Cesler-Maloney⁴, William R Simpson⁴, James R Campbell⁴, Athanasios Nenes^{1

5

6}, Jingqiu Mao⁴, Rodney J Weber¹

Affiliations

¹ School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, Georgia 30332, United States.
² Department of Environmental Health & Engineering, Johns Hopkins University, Baltimore, Maryland 21218, United States.
³ Department of Chemistry, University of California, Irvine, California 92697, United States.
⁴ Geophysical Institute and Department of Chemistry & Biochemistry, University of Alaska Fairbanks, Fairbanks, Alaska 99775, United States.
⁵ Laboratory of Atmospheric Processes and their Impacts (LAPI), School of Architecture, Civil & Environmental Engineering, Ecole Polytechnique Fédérale de Lausanne, Lausanne 1015, Switzerland.
⁶ Center for Studies of Air Quality and Climate Change, Institute of Chemical Engineering Sciences, Foundation for Research and Technology Hellas, Patras 26504, Greece.

Abstract

The oxidative potential (OP) of outdoor PM_2.5 in wintertime Fairbanks, Alaska, is investigated and compared to those in wintertime Atlanta and Los Angeles. Approximately 40 filter samples collected in January-February 2022 at a Fairbanks residential site were analyzed for OP utilizing dithiothreitol-depletion (OP^DTT) and hydroxyl-generation (OP^OH) assays. The study-average PM_2.5 mass concentration was 12.8 μg/m³, with a 1 h average maximum of 89.0 μg/m³. Regression analysis, correlations with source tracers, and contrast between cold and warmer events indicated that OP^DTT was mainly sensitive to copper, elemental carbon, and organic aerosol from residential wood burning, and OP^OH to iron and organic aerosol from vehicles. Despite low photochemically-driven oxidation rates, the water-soluble fraction of OP^DTT was unusually high at 77%, mainly from wood burning emissions. In contrast to other locations, the Fairbanks average PM_2.5 mass concentration was higher than Atlanta and Los Angeles, whereas OP^DTT in Fairbanks and Atlanta were similar, and Los Angeles had the highest OP^DTT and OP^OH. Site differences were observed in OP when normalized by both the volume of air sampled and the particle mass concentration, corresponding to exposure and the intrinsic health-related properties of PM_2.5, respectively. The sensitivity of OP assays to specific aerosol components and sources can provide insights beyond the PM_2.5 mass concentration when assessing air quality.