High Abundance of Fluorescent Biological Aerosol Particles in Winter in Beijing, China

Primary biological aerosol particles (PBAP) such as pollen, fungal spores, bacteria, and viruses represent a major subset of particulate matter for both coarse and fine aerosols. Although PBAP affect climate and human health, there still remains a large uncertainty regarding their sources and characteristics, especially in urban atmospheres. Here we combined online fluorescent biological aerosol particle measurements and offline fluorescent and biomarker analysis in winter in Beijing, a city suffering from severe air pollution. Our results show that the abundance of fluorescent biological particles was higher than that of many other natural environments. Bioaerosol loadings were greatly enhanced during mealtime, indicating local emissions of bioaerosols from human activities. The contributions of fungal spores to total organic carbon (OC) from fluorescent bioaerosol analyses were estimated to be around 10% both in clean and polluted periods. This study highlights the importance of human activities to emit bioaerosols into the atmosphere and the potential uncertainties of modeling bioaerosol effects in climate systems.