Assessment of the Sources, Distribution and Interanual Variability of PAN over North America using New Observations from TES.

Abstract:

Peroxyacetyl nitrate (PAN) is an important trace gas that serves to transport nitrogen oxide radicals (NO_x = NO + NO₂) throughout the troposphere. PAN is observed to form rapidly in fire plumes from the oxidation of short-lived volatile organic compounds (VOCs) in the presence of NO_x. It is thought that efficient PAN production in smoke plumes may lead to relatively efficient downwind ozone (O₃) production if PAN decomposition serves as an important source of NO_x. North America has a relatively long biomass burning season; fires are observed in many different locations over North America during late spring and summer. Here, we present the first measurements of elevated PAN from Tropospheric Emission Spectrometer (TES) over western North America during biomass burning season (late spring through summer). We investigate the relationships between the observed interannual variability of elevated PAN and fires, temperature, meteorology and long-range transport.