| Microorganism, the important component of particles in hazy weather, is one of the main factors of influencing human health. However, few researches have reported the change of community structure and the potential pathogenicity of microorganism, also few investigations have studied the influence of air quality level and human activities on air microorganism. The investigation of community structure and potential pathogenicity of microorganism on the particles from hazy weather has important significance in both the research of hazy component and its influence on human health.This paper investigated the morphology, community structure and potential source of microorganisms carried by particulate matter in various size under different air quality levels; investigated the change of community structure of microorganisms in day and night air under different air quality levels; established a Pathogens library -Human Pathogen Database, which is related to human health; also determined the species, content and its potential harm to human health of pathogenic bacteria in the spring and winter air. The major research results are as follows:1. The morphology, community structure and potential source of microorganisms carried by particulate matter in various size under different air quality levels were studied.? The amount of microorganism attached to particles increases with the increase of air particle size and the decrease of air quality level. These microorganisms are usually coccuses and bacillus, which present as a group. No typical fungus and pollen grains have been found in winter.? The component of bacterial community carried by air particles is affected by both air quality levels and particle size. These bacteria are mainly Proteobacteria, Cyanobacteria, Firmicutes, Actinobacteria, and Bacteroidetes, in which the Proteobacteria are most abundant, and its relative abundance level is about 24.63%?54.22%.? The bacterial communities carried by each air particle sample are very similar, but it is quite different from these bacteria communities in surface soil samples, ground dust samples and water samples which surround the sample spot. It indicates that some of these communities may come from long distances-transportation of air.2. The influence of human activities in the air of day and night under different air quality levels on the change of microbial community structure were studied.? The bacteria and fungi in each sample have similar species abundance and community structure. The bacteria are mainly Proteobacteria, Cyanobacteria, Firmicutes and Bacteroidetes. The fungi are mainly Ascomycota and Basidiomycota.? The community structure of bacteria and fungi in the same air quality level are basically similar, while it varies a lot in the samples of different air quality levels. When the air quality level is mild contamination, the Proteobacteria has the superiority in bacteria communities, of which the relative abundance is up to 86.8%; in fungi communities, Ascomycota has the absolute superiority and its relative abundance level is up to 99.9%.?The number of bacteria species is basically equivalent in both day and night, while the number of fungi species in the night is more than that of daytime. The community structure similarity of bacteria and fungi between the samples collected in daytime are higher than that of night, which indicates that human activities in the daytime promote the community structure similarity of the bacteria and fungi in samples.3. The species and content of pathogen in spring and winter air and its potential harm to human health were studied.?38 kinds of pathogen were found in 14 air particle samples of different particle sizes in winter, and the pathogen of higher content are concentrated in PM2.5 samples. Among the 24 PM2.5 samples in spring,14 kinds of pathogen were found, and 6 kinds of them are the same with samples in winter.The number of pathogen in spring is less than that in winter because that the air quality levels in spring is better than that in winter.?The content peak of pathogen on PM2.5 and PM10 particles in winter are usually appears in the air quality levels of moderate and severe pollution, while the content peak of pathogen on PM2.5 particles in spring are usually appears in the air quality between good and light pollution in PM2.5 samples. With the decrease of air quality levels, the content of most pathogen shows a rising trend. In spring, the peak of pathogen appears early, resulting the higher incidences of disease when air pollution was serious.? When the air quality level is from good to moderate or severe pollution, if the air microbial detection shows that the relative abundance of Bacteroides and Proteobacteria rises sharply, we can speculate that the species and content of pathogen has rised. More attention should be payed to personal hygiene, especially in vulnerable groups. It's also necessary for medical departments to make preventive measures against pathogen. |
PDF Full Text Request