Concentration and size distribution of viable bioaerosols during non-haze and haze days in Beijing

Abstract

Accumulation of airborne particulate matter (PM) has profoundly affected the atmospheric environment of Beijing, China. Although studies on health risks have increased, characterization of specific factors that contribute to increased health risks remains an area of needed exploration. Chemical composition studies on PM can readily be found in the literature but researches on biological composition are still limited. In this study, the concentration and size distribution of viable airborne bacteria and fungi were determined in the atmosphere from May to July 2013 in Beijing, China. Samples were collected during non-haze days and haze days based on the value of air quality index (AQI) PM2.5. Multiple linear regression results indicated that concentrations of viable bioaerosol exhibited a negative correlation with PM2.5 (AQI) ranging from 14 to 452. There was a little difference in size distribution of bioaerosol between non-haze and haze days that all airborne bacteria showed skewed trends toward larger sizes and airborne fungi followed a Gaussian distribution. Spearman's correlation analysis showed that a fraction of bioaerosol with fine and coarse particles had negative and positive relations with PM2.5 (AQI), respectively. Moreover, the temporal variation of d g (aerodynamic diameter) of bioaerosol with PM2.5 (AQI) fluctuated from 9:00 to 21:00, which suggested that their deposition pattern would vary during a day. The primary research in this study implied that aerodynamic size variation should be considered in assessing the bioaerosol exposure during haze weather.

Time- and size-resolved bacterial aerosol dynamics in highly polluted air: new clues for haze formation mechanism

“…Here, for the first time we have captured the size-and time-resolved massive microbial level increase and structure shift events in high PM 2.5 polluted air in Beijing using a high-volume portable aerosol sampler up to 1000 L/min. Traditionally, people often use low flow rate sampler such as BioSampler (SKC, INc., flow rate=12.5 L/min) and the 4-channel PM sampler (16.7 L/min) or sometimes up to 100 L/min, but most for short time samplings(Gao et al, 2015b;Yuan et al, 2017). These samplers with low sampling rates often fail to capture rapid but transient microbial events in the air since newly bacterial aerosol dynamics could be quickly diluted by open ambient air, and such time-resolved events could also discontinue as atmospheric conditions change from the air.…”

Characteristics of bacterial community in cloud water at Mt Tai: similarity and disparity under polluted and non-polluted cloud episodes

“…Relevant studies suggested that the bacterial community was highly variable under different PM 2.5 mass concentrations (Cao et al, 2014). Statistical analysis, e.g., correlation or multiple linear regression, indicated that PM 2.5 exhibited a negative correlation with airborne bacteria on haze days (Gandolfi et al, 2015;Gao et al, 2015), whereas in another study, Spearman correlation analysis showed that PM 2.5 exhibited a significant positive correlation with the airborne microbe concentration (Dong et al, 2016). Possibly, the inorganic and organic compounds in particulate matter (PM 2.5 ) can be available nutrients for microbial growth in air.…”

Characterization of particulate matter concentrations and bioaerosol on each floor at a building in Seoul, Korea

“…Several studies have been conducted on indoor and outdoor PM concentrations related to bioaerosols and diseases (Gao et al 2014;Ha et al 2011;Jo and Seo 2005;Kim et al 2012;Tina and Barbara 2008;Zorman and Jersek 2008), but few of them combined ventilation characteristics with indoor and outdoor PM correlations on each floor of the building in Korea.…”