Investigation of Indoor and Outdoor Fungal Bioaerosols and Environmental Factors in Indoor Air Quality of Nursery Schools

Bioaerosols are airborne particles that contain bacteria, viruses, and fungi. Human reactions to bioaerosols are very different. This study attempted to determine indoor and outdoor fungal density in nursery schools in Birjand city and compares the relationship between air fungus density and particulate matter (PM) with mean temperature and relative humidity (RH) in three seasons: Fall, Winter, and Spring. This cross-sectional study was conducted in six nursery schools within a period of 2017-2018. Bioaerosols sampling from the indoor and outdoor air was performed by air-trapping method (28.3 L/min) for 35 min, collected in Sabouraud dextrose agar medium. The air temperature and relative humidity (RH) were measured. The mean temperature of indoor and outdoor was 23.49±4.259 and 20.87±5.57, and the relative humidity of 36.04±12.86 and 22.4±7, respectively. The most isolated fungal species was Penicillium spp. There is a difference between the dispersal of fungi and suspended particles and the humidity of the two environments (p=0.001). Moreover, there is only a difference in the distribution of fungi in fall (p=0.035). Generally, the contamination of indoor is linked to a load of outdoor airborne fungal spores. It can be safely concluded that bioaerosol has outdoor sources and ventilation plays an important role in improving the quality of the indoor air.