Bacterial and fungal aerosols in rural nursery schools in Southern Poland

This study aimed to characterize airborne bacteria and fungi populations present in rural nursery schools in the Upper Silesia region of Poland during winter and spring seasons through quantification and identification procedures. Bacterial and fungal concentration levels and size distributions were obtained by the use of a six-stage Andersen cascade impactor. Results showed a wide range of indoor bioaerosols levels. The maximum level of viable bacterial aerosols indoors was about 2600 CFU·m^-3, two to three times higher than the outdoor level. Fungi levels were lower, from 82 to 1549 CFU·m^-3, with indoor concentrations comparable to or lower than outdoor concentrations. The most prevalent bacteria found indoors were Gram-positive cocci ( > 65%). Using the obtained data, the nursery school exposure dose (NSED) of bioaerosols was estimated for both the children and personnel of nursery schools. The highest dose for younger children was estimated to range: 327-706 CFU·kg^-1 for bacterial aerosols and 31-225 CFU·kg^-1 for fungal aerosols. These results suggest an elevated risk of adverse health effects on younger children. These findings may contribute to the promotion and implementation of preventative public health programs and the formulation of recommendations aimed at providing healthier school environments..