| The concentration of microorganisms in the air is one of the important standards for air quality.At present,China has already had recommendations for evaluation of atmospheric microorganisms.However,there are few studies on the evaluation criteria,distribution characteristics,influencing factors and exposure levels of microbial aerosols in different types of buildings,such as libraries,gymnasiums,laboratories,hospitals and so on.Universities and hospitals are places with high flow of people and frequent activities,and the level of indoor microbial pollution in these places affects people's health.Therefore,in-depth study on the distribution characteristics,influencing factors and exposure levels of indoor microbial aerosols in different buildings is of great significance to improve indoor microbial pollution levels,protect human health and provide basic data for the establishment of indoor microbial standards.Through comparing and analyzing the influence of different sampling time and different sampling methods on the results of microbial aerosol test,the sampling scheme of microbial aerosol was optimized.The paper mainly tested the indoor and outdoor concentration of microbial aerosols in different functional buildings,and simultaneously tested the temperature,relative humidity,particulate matter,CO2 and formaldehyde concentration.Through the statistical analysis of the test data,the concentration distribution characteristics and particle size distribution characteristics of microbial aerosols in different functional buildings were studied,and the correlation with environmental quality parameters was analyzed.The microbial exposure levels of different populations in the universities and hospital were evaluated.The main conclusions were as follows:?1?Compared with the sampling effect of micro-aerosol by natural sedimentation method,the impact sampling method had strong anti-interference ability to the environment,relatively high precision,and better capture effect on microbial aerosol.Selecting a reasonable sampling method and sampling time could improve the capture efficiency of microbial aerosols.?2?The concentration of bacterial aerosol in different functional buildings of universities was?1173340?cfu/m3,and the fungal aerosol was?791145?cfu/m3.The ratio of B/F ratio of indoor bacteria to fungi in various places of universities was 0.0986.18.The concentration of bacterial aerosol in the hospital was?82841?cfu/m3,and the fungal aerosol was?60354?cfu/m3.The B/F value of hospitals was 1.915.10.In winter,the indoor B/F value was greater than 1 in the most places,and the concentration of bacterial aerosol was higher than fungi aerosol,and the B/F value was greater than 1.The intensity of the source of bacteria was higher than fungal in the sites.?3?The particle size distribution characteristics of bacterial and fungal aerosols in different functional buildings were different.The median diameters of bacterial and fungal aerosols in universities were 2.253.59?m and 2.072.73?m,respectively.The median diameters of indoor bacterial and fungal aerosols in hospitals were 2.333.75?m and 2.432.69?m,respectively.The indoor median diameter of microbial aerosols in buildings was smaller than that of outdoor.?4?The temperature and relative humidity range of different functional buildings in hospitals and universities were 16.523.1°C and 12.327.2%,respectively.The temperature and relative humidity was no significantly positively correlated with bacterial and fungal aerosol.The mass concentration range of PM1,PM2.5 and PM10 of different functional buildings were 0.0030.075mg/m3,0.0050.85mg/m3 and 0.0130.100mg/m3,respectively.The bacterial concentration was significantly positively correlated with PM2.5 and PM10,and the Spearman correlation coefficients were 0.281 and 0.346,respectively.The fungal concentration was significantly positively correlated with PM1 and PM2.5,and the Spearman correlation coefficients were 0.314 and 0.273,respectively.?5?The CO2 concentration range of different functional buildings in hospitals and universities was 7041974ppm.The CO2 concentration was significantly positively correlated with bacterial,and the Pearson correlation coefficient was 0.317,but there was no significant correlation with the fungal aerosol concentration.The concentration range of formaldehyde of different functional buildings was 0.020.10ppm,and the indoor formaldehyde concentration was no significantly negatively correlated with the bacterial and fungal aerosol concentrations.?6?There was a correlation between indoor environmental parameters.Relative humidity and PM1 were significantly positively correlated with temperature,and the correlation coefficients were 0.513 and 0.302,respectively.The relative humidity was significantly positively correlated with PM1 and PM12.5,and the correlation coefficients were 0.539 and0.438,respectively.There was no significant correlation between CO2 and temperature,relative humidity,PM1 and PM12.5,but there was a significant positive correlation with PM2.510,and the correlation coefficient was 0.350.The correlation coefficient between PM1 and PM2.5 was0.994,and the correlation coefficient between PM2.5 and PM10 was 0.911.The correlation between PM1 and PM2.5 in particulate matter was stronger than that between PM2.5 and PM10.?7?The indoor daily potential exposure of bacterial and fungal aerosols to different populations in different functional buildings of universities ranged from 98 to 15878cfu/d and from 91 to 6323cfu/d,respectively.The indoor daily potential exposure of bacterial and fungal aerosols to different populations in different places of hospitals ranged from 144 to 4183cfu/d and from 50 to 1601cfu/d,respectively.The average potential daily exposure of microbial aerosols to different populations in schools and hospitals varied greatly.The average daily exposure of microbial aerosols in dormitory was significantly higher than other places.?8?The concentration level of indoor microbial aerosol was affected by the combination of spatial structure,indoor environmental parameters and personnel activities.The concentration of microbial aerosol in different functional buildings was non-uniform.Testing the microbial aerosol concentration with Kruskal-Wallis of every places,the significance value Sig<0.05,which was significantly different and statistically significant. |
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