Biomass burning (BB) affects fine particulate matter (PM_2.5) and ozone (O₃) formations by emitting their gaseous precursors and primary aerosols. In the study, impacts of BB in peninsular Southeast Asia (BB-PSEA) are evaluated on the PM_2.5 and O₃ formations in southern China, using a source-oriented WRF-Chem model to simulate an air pollution episode from 21 to 25 March 2015. The source-oriented model separates the emission from the BB-PSEA and other sources and is able to evaluate the effect of aerosol-radiation interactions (ARI) and aerosol-photolysis interactions (ARI) from the BB-PSEA. Comparisons with observations reveal that the model performs well in simulating the air pollution episode. Sensitivity experiments show that PM_2.5 contribution of the BB-PSEA is 39.3 μg m^-3 (68.0%) in Yunnan Province (YNP) and 8.4 μg m^-3 (24.1%) in other downwind areas (ODA) in southern China on average. The PM_2.5 enhancement is mainly contributed by the increase of primary aerosols in YNP but by secondary aerosols in the ODA. The BB-PSEA contributes to O₃ concentrations ([O₃]) of 18.1 μg m^-3 (19.4%) in YNP and decreases [O₃] in the ODA by 3.7 μg m^-3 (5.3%). The increase of [O₃] in YNP is contributed by the gaseous emissions of the BB-PSEA, and the decrease of [O₃] in the ODA is caused by the combined effect of ARI and API due to the BB-PSEA. The NH₃ emission from the BB-PSEA plays a key role in the enhancement of secondary inorganic aerosols in southern China, and also determine the PM_2.5 increase in the ODA.
 

WRF-Chem,生物质燃烧,PM2.5,O3