| Building indoor airborne microbial contamination is the source of the respiratory tract,allergic and infectious diseases that can’t be ignored,filtration and purification is an important method to control indoor airborne microbial contamination.Public buildings are indoor places with a high concentration of people and strong cross-infection,once indoor airborne microbial contamination occurs,it poses a great health threat to people.With the increase of indoor air hygiene emergencies in public buildings,people are paying more attention to the issue of indoor airborne microbial contamination in public buildings.Therefore,in this study,the typical public buildings represented by library building,office building,and medical building are selected as the research objects,the indoor airborne microbial contamination characteristics were explored and the control effect of the application of filtration and purification methods were evaluated mainly by field measurement combined with the culturing method and high-throughput sequencing method.The main contents are as follows:（1）The indoor airborne microbial contamination characteristics of the library functional rooms,offices,and the medical functional areas have the following common point.The indoor airborne microbial concentration in the library function rooms,offices,and medical function areas all exceeds the corresponding standard concentration limit.The inhalable portion of indoor airborne microorganisms（<4.7μm）accounts for over 60%.There are many kinds of airborne pathogenic fungi in indoor airborne fungi and they have different negative health effects.Men are exposed to higher levels of indoor airborne microorganisms.The problem of indoor airborne microbial contamination in public buildings should be promptly controlled.（2）The spatial and temporal distribution of airborne fungal concentration in library functional rooms showed significant differences.The mean indoor airborne fungal concentration in the reading room and study room with dense personnel and long stays was higher than that in stacks.The highest mean indoor airborne fungal concentration of the reading room,study room,open stack,and compact stack was in autumn.The dominant range of indoor airborne fungal particle size of the library functional rooms was 1.1-3.3μm,and the inhalable portion of indoor airborne fungi（<4.7μm）accounted for over 80%.A total of 18 pathogenic fungi（such as Malassezia and Cladosporium）were detected in the indoor air environment of library functional rooms.The dominant indoor airborne fungal genera in the four seasons of each functional room all had airborne pathogenic fungi.The exposure risk assessment analysis showed that male employees were exposed to the highest indoor airborne fungal levels in the autumn.The statistical analysis results indicate that the outdoor airborne fungal concentration was the dominant parameter for the variations in indoor airborne fungal concentration,and the contribution of indoor and outdoor sources and the status of indoor facilities to the variations in indoor airborne fungal concentration was greater than that of indoor environmental parameters.（3）There was a strong positive correlation between the indoor and outdoor airborne fungal concentration（p<0.05）,and the infiltration of outdoor airborne fungi can affect the variations in indoor fungal concentration in the offices.The dominant particle size range of indoor airborne fungi was 1.1-3.3μm,and the inhalable portion of indoor airborne fungi（<4.7μm）was as high as 89%.The highest relative abundance of fungi in indoor air environments was airborne pathogenic fungi（Cladosporium）.The exposure dose results indicated that male students were exposed to the highest levels of indoor airborne fungi.Operating indoor air disinfection cleaner can effectively control indoor airborne fungal contamination.However,the impact of outdoor airborne fungal infiltration on the control effect of the purifier should be considered.The indoor airborne fungal concentration decreased by 453～1492 CFU/m3after purification,the highest indoor airborne fungal purification efficiency and particle size measurement efficiency can reach 88%and 94%,respectively,and the highest energy consumption for indoor airborne fungal purification was 2.1×10-4 k W·h/CFU.（4）There were significant differences in the spatial distribution of indoor airborne microbial concentration in medical functional areas,and the mean concentration or colony number of airborne bacteria and fungi in the outpatient department with frequent personnel mobility and closely connected to the outdoor environment was greater than that of operating rooms and wards.The dominant particle sizes of indoor airborne bacteria and fungi in the medical functional areas were 1.1-4.7μm and 1.1-3.3μm,respectively.The inhalable portion of indoor airborne bacteria and fungi（<4.7μm）accounted for over 60%and 67%,respectively.The indoor airborne microbial exposure risk of male children in the ward and male doctors in the outpatient department was the highest.Operating purification units and fresh air fans can control indoor airborne microbial contamination.However,the control and purification effect of the fresh air fan should be optimized.The indoor airborne microbial concentration and the colony number after purification in the operating room meet the current standard concentration limits,the indoor airborne bacterial concentration after purification in the ward and outpatient department exceeds the concentration limit of100 CFU/m3,the indoor airborne fungal concentration after purification in the outpatient department exceeds the concentration limit of 500 CFU/m3,the highest indoor airborne microbial purification efficiency and particle size measurement efficiency can all reach 100%,and the highest energy consumption for indoor airborne microbial purification was 3.8×10-3 k W·h/CFU.This study explores the contamination characteristics of indoor airborne microorganisms and evaluates the control effectiveness of the application of filtration and purification methods for indoor airborne microbial contamination in public buildings.It provides theoretical guidance for the preventive protection of indoor personnel health in public buildings and provides a reference for the application of indoor airborne microbial contamination filtration and purification control methods. |
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