Assessment of bioaerosol concentration in the indoor environments

Bioaerosol is defined as airborne particles such as living organisms include bacteria, fungi and their related metabolites, such as endotoxin. Over the recent years, health effects of bioaerosols such as infectious and respiratory diseases, acute toxic effects, allergies and cancer have been considered. The aim of this study was to evaluate the bacterial and fungal concentrations in indoor air of various environments. This cross - sectional study was conducted in 2013. A single-stage Andersen biosampler was used for the bacterial and fungal collection in the air of indoor environments. A total of 240 samples (60 samples of bacteria and 60 samples of fungus with repeat) were analyzed. The effects of environmental factors such as temperature and humidity on bioaerosol concentrations were also evaluated. The highest average concentration of airborne bacteria was seen in the residential environments 944 CFU/m3 and the highest fungal concentration 102 CFU/m3 was obtained in school classrooms. However, indoor air of offices and university classrooms had the lowest concentration of bacterial and fungal bioaerosols with the overall mean of 132 and 36 CFU/m3, respectively. According to the results, the bioaerosol concentration in the indoor air of some environments was higher than of WHO guideline, which can cause health risks and respiratory diseases, especially in children and people who are sensitive. Increasing the ventilation rate by mechanical equipment or natural systems can be effective in improving indoor air quality