Contribution of autumn biomass burning to organic aerosol in the Pearl River Delta region

In this study, we applied thermal desorption chemical ionization Time-of-Flight mass spectrometer (FIGAERO-ToF-CIMS) to obtain high temporal resolution (i.e., hourly) measurements of levoglucosan, which is a widely-used tracer for biomass burning emissions. Using the dataset, we estimate the contributions of biomass burning to organic aerosol (OA) at an urban and a regional site in the autumn of Pearl River Delta (PRD) region. The results demonstrated that the average concentrations of levoglucosan at the urban and regional sites in the autumn PRD region were (0.07 ± 0.08) and (0.14 ± 0.12) µg/m3, respectively. We show that concentrations observed at the regional site were higher than the urban site. The diurnal variation of levoglucosan peaked in the morning and at night at both sites. It was observed that levoglucosan was poorly correlated with CO and acetonitrile at both sites, whereas significantly positive correlation was obtained with OA. The average contributions of biomass burning to OA were further estimated based on the tracer method to be 7.4% (urban site) and 11.4% (regional site), respectively, with significantly higher contributions at night than during the day. © 2023 Chinese Society for Environmental Sciences. All rights reserved.