Sensitivity of tropospheric ozone to chemical kinetic uncertainties in air masses influenced by anthropogenic and biomass burning emissions

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Ridley, DA 
Cain, ML 
Methven, J 
Arnold, SR 

We use a Lagrangian chemical transport model with a Monte-Carlo approach to determine impacts of kinetic rate uncertainties on simulated concentrations of ozone, NOy and OH in a high-altitude biomass burning plume and a low-level industrial pollution plume undergoing long-range transport. Uncertainties in kinetic rate constants yield 10 - 12 ppbv (5th to 95th percentile) uncertainty in the ozone concentration, dominated by reactions that cycle NO and NO₂, control NOₓ conversion to NOy reservoir species, and key reactions contributing to O₃ loss (O(¹D)+H₂O, HO₂+O₃). Our results imply that better understanding of the PAN thermal decomposition constant is key to predicting large-scale O₃ production from fire emissions and uncertainty in the reaction of NO+O₃ at low temperatures is particularly important for both the anthropogenic and biomass burning plumes. The highlighted reactions serve as a useful template for targeting new laboratory experiments aimed at reducing uncertainties in our understanding of tropospheric O₃ photochemistry.

37 Earth Sciences, 3701 Atmospheric Sciences, 41 Environmental Sciences, Climate-Related Exposures and Conditions, 13 Climate Action
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Geophysical Research Letters
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National Centre for Atmospheric Science (NERC) (via University of Leeds) (R8/H12/83/003)