| In recent years, with the development of the social economy and the improvement of the people’s living standard, the environment becomes more and more serious. Air is one of the important indispensable environmental factors to human survival, also is one of microbial proliferation medium. Bio-aerosol is one of the most important roles of aerosols. It is one of the most serious threat to human health, and can seriously affect the ecological environment and climate. At the same time, the characteristic of bioaerosols varies with the geographical environment and climate conditions, and the present domestic research is relatively limited. Therefore, to understand the dynamic change rule and pollution degree of bio-aerosol systematically and comprehensively has important significance. Thus, to quantify the characteristics of microbial aerosols during various weather conditions, sampling was carried out in the site of guanzhong of Xi’an using a six-stage cascade impactor from July, 2014 to August, 2015. The results are as follows:(1) The concentration of culturable bacteria aerosols ranges from 96.88 CFU?m-3 to 1908.60 CFU?m-3, and the culturable fungi aerosols ranges from 67.32 CFU?m-3 to 1736.53 CFU?m-3 from July, 2014 to August, 2015.(2)The distribution characteristics of culturable microorganisms varies over different months and seasons. The monthly average concentrations of culturable bacteria aerosols were in the ranges of 240.47CFU?m-3~1004.81CFU?m-3, the seasonal average concentrations appeared to be higher in autumn and winter, and lower in spring and summer; The monthly average concentrations of culturable fungi aerosols were in the ranges of 197.11CFU?m-3~765.54CFU?m-3, the seasonal average concentrations appeared to be higher in spring and autumn, and lower in summer and winter. For the size distribution of culturable microorganisms, different seasons of culturable microbial aerosols had no significant difference(P>0.05).(3) The distribution characteristics of culturable microorganisms varies under different weather conditions. In general, the order of the culturable microorganisms was raining days<sunny days<cloudy days<haze days, and the concentration in haze days was significantly higher than the other three kinds of weather conditions. Moreover, The concentration showed in this study can compare to the outdoor standard recommended by the Chinese academy of sciences, and the concentration during haze days was higher than this level.(4) The size distribution of culturable microorganisms varies under different weather conditions. Compared with sunny days, the number median diameter in cloudy day was bigger than in the sunny days. When the raining days and haze days came, the number median diameter became smaller. The concentration in the six stages of culturable bacteria aerosols during cloudy days and haze days was bigger than the concentration in the sunny days, but the concentration in raining days became less.(5) The relationship of bioaerosols with meteorological and environment factors was analyzed in detail. This study suggested that the culturable bio-aerosols showed negative correlation with temperature, and positive correlation with wind speed and relative humidity. At the same time, the culturable bio-aerosols showed positive correlation with PM10、PM2.5. Moreover, SO2、N02 and CO showed positive correlation with culturable bacteria aerosols, but showed negative correlation with culturable fungi aerosols, O3 showed negative correlation with culturable bio-aerosols, but it is not significant.. |
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