AsianScientist (Oct. 23, 2015) – Researchers have conducted a screening of the biological components in the air of 11 provinces in China. Their study, published in Science Bulletin, is the first of its kind in terms of scale.
When people talk about air pollution, PM2.5 immediately comes into mind. Yet, we are often not aware that these tiny particles in the air could be living microbes, e.g., bacteria, fungal spores, and viruses. Some of these living particles could be human pathogens or opportunistic ones which can cause serious health outcomes.
Over the past decades, the chemical compositions of particulate matter have been extensively studied, especially in mega cities. However, despite of their importance, few studies were conducted for biological components of air samples, especially on a large scale. Information about their distribution and concentration was lacking, particularly in different climate zones.
A team led by Professor Yao Maosheng from the State Key Joint Laboratory of Environmental Simulation and Pollution Control at Peking University developed a biological sensor called ultraviolet-aerodynamic particle sizer (UV-APS) to track living organisms in air pollution. Transported using an automobile, this probe reached as many as 11 provinces in China.
The UV-APS detects the size distribution and concentration level of viable microbial aerosol particles by measuring their intrinsic fluorescence level emitted. In previous studies, most of the monitoring was confined to single location which is often in a pristine environment, thus only representing those of natural emissions.
In the present study, the researchers monitored the microbial aerosol levels both in major cities (highly polluted) and their suburbs (less polluted). In addition, they also studied the bacterial aerosol structures using a gene sequencing technique.
The team detected about 104 to 105 viable microbial aerosol particles per m3 in the ambient air. Bacillus was found to be the dominant bacteria. The microbe size distributions were also different in different parts of China. These differences were attributed to the different climate of the regions.
“These unique microbial aerosol distribution patterns might serve as a fingerprint for a particular region,” said Yao.
Furthermore, the team has discovered that locations with a higher level of air pollution also tend to exhibit a higher level of airborne bacterial diversity and concentration.
Li Jing, a PhD student from the team, added, “We have detected significant differences in bacterial aerosol community structures for different climate zones in China using an automobile air conditioning filter method. For example, Hainan has a lower bacterial aerosol diversity compared to that in Beijing.”
Scientists are still at work to find out the relevant mechanism involved in the regulation of fluctuations of bioarosol particles through a haze period in Beijing. In addition, they are also examining the link between air pollution and increased number of hospital visits for respiratory infections.
“Although the results from this work are limited to short-term monitoring at each particular location this is the first ever attempt in understanding the airborne microbial community on such a large scale. Certainly, more in-depth studies are needed to elucidate the impacts of these microbes from the air on our health, ecology and climate,” Yao said.
The article can be found at: Wei et al. (2015) Microbial Aerosol Characteristics in Highly Polluted and Near-Pristine Environments Featuring Different Climatic Conditions.
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Source: Science China Press.
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