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

Abstract

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.

Abundance and Diurnal Trends of Fluorescent Bioaerosols in the Troposphere over Mt. Tai, China, in Spring

“…In addition, FL B and FL C particles in fine mode still strongly correlated with the fine mode non‐FAPs (For FL C, 3σ: R 2 = 0.72–0.90; 6σ: R 2 = 0.69–0.90; 9σ: R 2 = 0.67–0.88), which indicates that they might have similar source with non‐FAPs. This is similar to the findings in winter in Beijing (Yue et al, ) and is also indicated by the moderate correlations with biomass burning tracers (Tables S8 and S9).…”

“…This can be explained that as particle size increases, the increasing quantity of constituent biomolecules leads to fluorescence intensity exceeding the baseline of other spectral band. This change pattern has also been observed in the atmosphere in winter in Beijing (Yue et al, ) and in laboratory experiments with nonbiological interferences (Savage et al, ). Collectively, as to number concentration, the fluorescent bioaerosols resided mainly in the fine mode (<~3 μm), while for mass concentration, they were dominated by coarse (2.5–10 μm) and Lcoarse particles (>10 μm; Figure S6).…”

“…The abundance of total FAP (>0.8 μm) in the ambient atmosphere by volume was 647 ± 533 L −1 (26.9% ± 10.0%, Figures and S6 and Tables S5 and S6), which is at the scale of the concentration for clean period in winter in Beijing (Yue et al, ), but one order of magnitude lower than the concentration in autumn in Nanjing (Yu et al, ). The most abundant type of FAP was FL B particles, which is the same as the observations in Beijing and Nanjing (Yu et al, ; Yue et al, ).…”

“…The abundance of total FAP (>0.8 μm) in the ambient atmosphere by volume was 647 ± 533 L −1 (26.9% ± 10.0%, Figures and S6 and Tables S5 and S6), which is at the scale of the concentration for clean period in winter in Beijing (Yue et al, ), but one order of magnitude lower than the concentration in autumn in Nanjing (Yu et al, ). The most abundant type of FAP was FL B particles, which is the same as the observations in Beijing and Nanjing (Yu et al, ; Yue et al, ). Laboratory experiments of bacteria, fungal spores, and pollen grains have very rarely measured these PBAP as FL B particles (Hernandez et al, ; Savage et al, ), although Perring et al () showed that some mold spores are detected as this type.…”

“…The average abundance of FL3 (281 L −1 ) fluorescent aerosol at this site was also higher than the Puy de Dôme mountain (95 L −1 ). Regional pollution can also lead to higher FAP concentration since nonbiological fluorophores may be included, which can be seen from the WIBS measurements in Beijing, another city frequently influenced by pollution of North China Plain (K. Wei et al, ; Yue et al, ). Alternatively, varying climatic zones, WIBS prototypes and FAP definitions may also contribute to these differences (Pöhlker, Huffman, et al, ; Savage et al, ).…”