posted on 2021-06-28, 17:36authored byJun Liu, Matthew J. Gunsch, Claire E. Moffett, Lu Xu, Rime El Asmar, Qi Zhang, Thomas B. Watson, Hannah M. Allen, John D. Crounse, Jason St. Clair, Michelle Kim, Paul O. Wennberg, Rodney J. Weber, Rebecca J. Sheesley, Kerri A. Pratt
Hydroxymethanesulfonate (HMS) is
produced in the aqueous-phase
reaction of formaldehyde (HCHO) and sulfur dioxide (SO2) and has been proposed as a significant contributor to midlatitude
wintertime pollution events. Here we report HMS detection within submicrometer
atmospheric aerosols during frequent late summer, regional fog events
in an Arctic oil field. The number fraction of individual particles
containing HMS increased during fog periods, consistent with aqueous-phase
formation. The single-particle mass spectra showed the primary particle
signature (oil field emissions), plus secondary oxidized organics
and sulfate, consistent with aqueous-phase processing. HMS mass concentrations
ranged from below the ion chromatography limit of detection (0.3 ng/m3) to 1.6 ng/m3, with sulfate concentrations of
37–222 ng/m3. HCHO and SO2 measurements
suggest that the fog HMS production rate is ∼10 times higher
in the oil fields than in the upwind Beaufort Sea. Aqueous-phase reactions
of local oil field emissions during frequent summertime regional fog
events likely have downwind impacts on Arctic aerosol composition.
The potential for fog-based HMS production was estimated to be an
order of magnitude higher in Fairbanks and Anchorage, AK, than in
the oil fields and may explain the missing organosulfate source contributing
to Fairbanks air quality.