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Ground-based FTIR Retrievals of PAN at the Polar Environment Atmospheric Research Laboratory

Peroxyacetyl Nitrate (PAN) is a key reservoir species of tropospheric nitrogen radicals (NOx = NO + NO2), having significant implications for the production of tropospheric ozone. The atmospheric lifetime of PAN is strongly temperature dependent, ranging from approximately 1 hour at 298K to several weeks at the colder temperatures of the upper troposphere and lower stratosphere (UTLS). This property allows PAN to be transported vast distances in the UTLS from mid-latitude sources to the high Arctic region, where it can influence NOx and O3 budgets, contributing to the pollution phenomenon known as ‘Arctic haze’. Previous measurements of PAN in the Arctic were made primarily on a campaign basis via in situ measurement techniques, providing limited information on long-term concentrations and trends. In this talk, I will describe a new ground-based retrieval method for PAN using the Bruker 125HR at the Polar Environment Atmospheric Research Laboratory (PEARL), allowing for a long time-series of total columns over the high Arctic to be estimated. Basic comparisons against measurements from the Infrared Atmospheric Sounding Interferometer (IASI) satellite instruments and the GEOS-Chem CTM were performed, and evidence of a significant enhancement in PAN total resulting from the long-range transport of biomass burning plumes in August 2017 will be presented.

Event series  Brewer-Wilson Seminar Series