Fairbanks sulfate isotope measurements during ALPACA (2022）

Within and surrounding high-latitude cities, poor air quality disturbs Arctic ecosystems, influences climate, and harms human health. The Fairbanks North Star Borough has wintertime particulate matter (PM) concentrations that exceed the Environmental Protection Agency’s (EPA) threshold for public health. Particulate sulfate (SO42-) is the most abundant inorganic species and contributes approximately 20% of the total PM mass in Fairbanks, but air quality models underestimate observed sulfate concentrations. Here we quantify sulfate sources using size-resolved δ34S(SO42-), δ18O(SO42-), and Δ17O(SO42-) of particulate sulfate in Fairbanks from January 18th to February 25th, 2022 using a Bayesian isotope mixing model. This data contains sulfur and oxygen isotope measurements for size-resolved filter samples collected during the Alaskan Layered Pollution and Chemical Analysis field campaign in 2022. Ambient concentrations of SO2, HMS, non-HMS S(IV), SO4, and the sulfur oxidation ratio are also included. Finally, the median fractional contributions of each oxidation pathway calculated in the Bayesian isotope mixing model are included with their 95% confidence interval.