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High-latitude Urban Air Quality: 20 Months of Aerosol Composition Data from Fairbanks, Alaska
ELLIS ROBINSON, Michael Battaglia, Meeta Cesler-Maloney, James Campbell, Athanasios Nenes, Jason St. Clair, Jingqiu Mao, Rodney J. Weber, William Simpson, Peter F. DeCarlo, Johns Hopkins University
Abstract Number: 558
Working Group: Urban Aerosols
Abstract
We present continuous, sub-hourly measurements of aerosol composition from Fairbanks, Alaska, USA that span the past 20 months (January 2020 to August 2021) and include times before and after the social and economic disruption of the Covid-19 pandemic. Conditions of extreme cold, minimal sunlight, and Fairbanks’ location within a river valley lead to wintertime aerosol concentrations that frequently exceed EPA 24-hour limits. We compare PM2.5 mass and composition measurements from winter 2020 (pre-Covid) with winter 2021 using an Aerodyne Aerosol Chemical Speciation Monitor (ACSM). The ACSM dataset identifies the relative contributions of different aerosol components to air quality in Fairbanks. Positive matrix factorization (PMF) of the mass spectral dataset is used to identify the major contributions to both organic and inorganic aerosol fractions, which include oxidized organic aerosol (OOA, 40-60% of OA mass), biomass burning OA (BBOA, 15-40%), and hydrocarbon-like OA (HOA, 15-25%). Wintertime sulfate concentrations display a diurnal pattern similar to HOA, implicating a primary vehicular source of sulfate in the region. Our analysis shows the relative contribution of the different major emissions sources to PM2.5 in Fairbanks, and how these sources change on diurnal and seasonal time scales and under the influence of different meteorological conditions.