Bacterial Community Structure Of Atmospheric Aerosol In Autumn And Winter In Xi'an

Atmospheric microbial aerosols are an important part of atmospheric aerosols,which are closely related to the ecological environment and life material of nature and play an important role in the energy flow and material circulation in nature.There is no fixed composition of the bacterial microbial community in the atmosphere because there is no nutrient and attachment point in the air that facilitates the direct growth and reproduction of microorganisms.Microbes in the atmosphere can enter into the body through the damaged skin and respiratory tract,causing a threat to human health and a variety of diseases.Microorganisms exist in the atmosphere in the form of communities.At present,the research on microbial community in the atmosphere is limited to the microbial concentration and particle size distribution,while the study to the microbial community structure is very few.In this study,the PM2.5 and PM10 microbial aerosols of autumn and winter in Xi'an were collected by using the ZR-3930 ambient air particulate integrated sampler.Based on the study to the bacterial community structure of the atmosphere in Xi'an by using the method of 16 S r RNA in bacterial,we have explored the following conclusions:(1)The dominant community of bacterial in the PM2.5 and PM10 of autumn and winter were Proteobacteria and Firmicutes.In the genus level,the dominant species in the autumn were Bacillus,Bacteroides and Lactococcu.The dominant species in winter were Pseudomonas,Lactococcus,Lactobacillus and Ochrobactrum.And there is a complex correlation between these dominant species.(2)Proteobacteria was significantly higher in the haze days than that in the non-haze days,but Bacteroidetes was higher at non-haze days.At the genus level,Bacillus,Pseudomonas were higher at haze day,while Lactobacillus was higher at non-haze days.(3)When the haze pollution increased,the change of bacteria content in PM10 was significantly larger than that in PM2.5.At the genus level,the dominant species in both particulate matter were Pseudomonas.When the haze pollution increased,the contents of different strainsvaried in the two samples.(4)When the haze pollution is serious,the air bacterial activity becomes larger and the reproductive capacity is increased.It will increase the health hazards to the human body.(5)During the analysis of the RDA to the different environmental factors and bacterial community structure in the atmosphere,we have found that O3 and relative humidity had a great influence on the bacterial community,and the effect of temperature and NO2 on the bacterial community structure was the second.There is also a correlation between different environmental factors.