Spatial distribution of atmospheric bioaerosols in Beijing, Hangzhou and Wuhan, China

Exposure to bioaerosols can have adverse effects on human health and contribute to allergies, asthma, infectious diseases and pulmonary conditions. Bioaerosols are airborne particles of microbial, animal and plant origin. Animal- and plant-derived particles, which may disperse over long distances, are being increasingly addressed by environmental studies in addition to microorganisms. In this study, air samples were collected in various planned areas of three cities in China (Beijing, Hangzhou and Wuhan) using a new liquid-based sampler. Animal, plant and bacterial components were quantified according to the expression levels of housekeeping genes via real-time PCR and analysis of cycle threshold (Ct) values. The level of animal-derived particles in the air of Hangzhou was higher than those in the other two cities. More bacterial particles than animal or plant particles were detected in the air in Beijing compared with other cities. We also found a negative correlation between the bacterial content of bioaerosols and relative humidity and a positive correlation between bacterial content and temperature. By contrast, bioaerosol animal content was positively correlated with relative humidity and negatively correlated with temperature. In summary, high levels of bacterial particles were detected in atmospheric samples in China, although the lower concentrations of animal- and plant-derived particles should not be ignored. These data may provide important evidence for structural analyses of animal- and plant-derived bioaerosols as well as for risk assessment.