Pollution characteristics and health risks of indoor airborne fungi in densely populated buildings

Indoor airborne fungi are one of the main pollutants in the indoor environment of densely populated buildings, and are the source of respiratory tract, allergic and infectious diseases that cannot be ignored. This study uses six-stage impact airborne microorganism samplers to collect indoor airborne fungal samples from the library building and the medical building, quantitatively assess the concentration and particle size distribution characteristics of indoor airborne fungi, and evaluate the health risks of indoor personnel. The results show that the indoor airborne fungal concentrations in the library building and the medical building are (731±262) CFU/m3and (1 516±633) CFU/m3, respectively, which both exceed the concentration limit of 500 CFU/m3prescribed by WHO, and the concentration of the indoor airborne fungi in the medical building also exceeds the concentration limit of 1 000 CFU/m3prescribed by ACGIH, indicating a serious airborne fungal pollution. The maximum particle size of indoor airborne fungi in the library building and the medical building all ranges from 2.1 to 3.3 μm, and the proportion of inhalable indoor airborne fungi (<4.7 μm) is as high as 85% and 93%, respectively. The health risk assessment results indicate that male employees and male doctors are exposed to the highest levels of indoor airborne fungi.