ZHU Ting from Tsinghua School of Life Sciences, JIANG Jingkun from SOE, and TIAN Geng from Tsinghua Center of Biomedical Analysis, jointly published a paper entitled Inhalable Microorganisms in Beijing's PM2.5 and PM10 Pollutants during a Severe Smog Event on Environmental Science & Technology (ES&T) on January 13, 2014. Nature pressed an online comment on the paper on January 31 (Nature doi:10.1038/nature.2014.14640).

Particulate matter (PM) is the primary pollutant affecting urban air quality. However, due to the limitations of traditional research methods, not much is known about the microbial composition of inhalable PM pollutants. This study employed metagenomic methods to analyze the microbial DNA sequences which were extracted from PM pollutants. The microbial composition of PM pollutants was identified at the species level for the first time. The results suggested that the majority of the inhalable microorganisms were soil-associated and nonpathogenic to human. Nevertheless, the sequences of several respiratory microbial allergens and pathogens were identified. These findings may serve as an important reference for smog prevention, public healthcare, and city planning.