Abstract
AbstractAcetone photolysis is a potentially important source of hydroperoxyl and hydroxyl radicals (HOx) to the upper troposphere. The extent to which acetone photolysis is a significant source of HOx in the upper troposphere is unclear in part because of scarce measurements of the acetone photolysis quantum yield (Φacetone) in the actinic region (i.e., λ > 300 nm). Past measurements of the Φacetone have derived temperature‐ and pressure‐dependent parameterizations that lead to significantly different conclusions about the importance of acetone to HOx formation in the upper troposphere. Here, we focus on previously published data to derive the recommended Φacetone for atmospheric chemical modeling. Using Stern‐Volmer analyses, we determine temperature‐ and pressure‐dependent Φacetone using updated measurements of fundamental acetone photolysis parameters. We also use simulations of the Φacetone produced from recent photophysical modeling to derive temperature‐ and pressure‐dependent parameterizations of the Φacetone. In contrast to the current Φacetone parameterization used in atmospheric chemical modeling, our parameterization reflects a predicted nonzero Φacetone in the wavelength region above 320 nm. Despite the increased Φacetone values in the higher wavelength region of the acetone photolysis action spectrum, the modeled effect on HOx production is not significantly different from HOx produced using the current recommended Φacetone parameterization. Uncertainties in the acetone photolysis mechanism remain; thus, more direct temperature‐ and pressure‐dependent measurements of Φacetone are warranted.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call