An Aerodyne high-resolution time-of-flight AMS was deployed at a suburban site in the Sichuan Basin, southwestern China, under high emission intensity, and unique geographical and adverse meteorological conditions. OA was the most abundant component (36 %) in PM1
, characterized by a relatively high oxidation state. The contributions of BBOA and BC to PM1
were high in primary emission episodes, highlighting the critical influence of biomass burning.