| With the development of social economy,people pay more and more attention to the quality of indoor air environment.Microbial aerosol is important factor in the indoor environment,including bacteria,fungi and viruses.When the human body is exposed to a high concentration of fungal aerosol for a long time,the risk of pneumonia,bronchitis,and skin damage has increased dramatically.The northern regions,such as Xi’an,enter autumn and winter,the outdoor air quality becomes poor due to various factors such as climate,and the interior air of the building is often affected.University library staff flow frequently,and a large number of precious books and documents are stored,which provides suitable living conditions for fungal aerosols,resulting in excessive concentration of fungal aerosols.It not only increases the risk of asthma and respiratory diseases in the human body,but also accelerates the mildew of the paper and reduces the storage period of the book.Therefore,research on the distribution characteristics and diversity of fungal aerosols in university libraries is practical significance for the health of teachers and students and the construction and management of libraries.This paper choose a university library in Xi’an in autumn and winter as the research object,and set sampling points in the intensive library,Chinese paper library,Chinese current reading room,study room,stairwell and outdoor.In order to analyze the fungal aerosol distribution characteristics in autumn and winter,the fungus was collected by solid impact method and liquid sampling method,and the structure composition of fungal community was detected by ITS high-throughput sequencing.The following conclusions were obtained:The concentration of inhalable particulate matter was monitored by air quality detector,the indoor and outdoor particulate matter concentration in winter library was greater than that in autumn,and the concentration was 2.6 times and 2.3 times in autumn,respectively;the outdoor particulate matter concentration was the largest among all sampling points,which was 121.3μg/m3;The relative content of fine particles in the inhaled particles is relatively large,accounting for 61.8%.During the sampling period,the temperature,relative humidity and wind speed around the sampling point were recorded,the indoor temperature range was 17.329.0℃,the relative humidity range was 23.6%67.3%,and the wind speed was 00.04 m/s.The fungus was collected by solid impact method,the average concentration of fungi in autumn was higher than that in winter,the intensive library was 671.8 CFU/m3,466.1 CFU/m3;the Chinese library was 658.1 CFU/m3,433.2 CFU/m3;and the outdoor of the Chinese library was 887.8 CFU/m3,604.8 CFU/m3;stairwell was 734.1 CFU/m3,537.1 CFU/m3,the Chinese current reading room was 895.8 CFU/m3,486.7 CFU/m3,study room was 786.1 CFU/m3,467.3 CFU/m3.Among all the sampling points,the concentration of fungi in the outdoor of the Chinese library and Chinese reading room was the highest,718 CFU/m3,650.4 CFU/m3;stairwell and study room,respectively,615.9 CFU/m3,594.8 CFU/m3,The minimum of the library is the intensive library and Chinese library is 548.4 CFU/m3,523.1 CFU/m3.The fungal aerosol particle size distribution gradually increases from the first level to the fourth level,then decreases,and fourth level is the largest,sixth level is the smallest,by observing the morphological characteristics of fungal colonies,the dominant genus was Aspergillus,Cladosporium and Alternaria,there was a positive correlation between particle concentration,temperature and relative humidity,number of people,book age and fungal concentration.The fungi were collected by liquid sampling method and combined with ITS high-throughput sequencing.The result showed that the Ascomycete and Basidiomycetes accounted for the most at the gate level,and the genus Verticillium and Gonatophragmium were dominant fungus at the genus level.Accounting for 15.9%and 4.7%of the total sequence,respectively.Aspergillus,Cryptococcus,Talaromyces and Ochroconis are pathogenic fungi,Aspergillus genus accounted for a relatively large proportion of 2.1%,the Chinese library has the highest concentration of fungal communities in the test room,The community diversity of the Chinese language library is the highest.According to the indoor and outdoor concentration distribution characteristics of fungal aerosol and PM2.5,in terms of natural ventilation control strategies,it is recommended to open the window to dilute the pollutants in the autumn morning.The outdoor pollutant concentration in the winter is higher than that in the room.Through reference to relevant literature,it is recommended that the number of air changes be3-4 times/hour. |
