The purpose of the study is to assess the level of bacterial and fungal contamination of the split system elements and air in air-conditioned rooms. The research method included the quantitative accounting of microorganisms on the surfaces of split-system filters and in the air of university classrooms. It was found that after an hour operation of the air conditioner, the number of microorganisms in the air decreased by 41.4%. At the same time, the microbial landscape changed in the direction of increasing the percentage of molds and coccal microorganisms, which indicates a high risk of atmospheric pollution in the classrooms.