Microbiological tests of the air in selected rooms of the Faculty of Civil Engineering and Environmental Sciences of the Białystok University of Technology were carried out from September 2023 to April 2024. The total number of psychrophilic and mesophilic bacteria, the number of actinobacteria, the number of Staphylococci, and the total number of fungi were determined in the tested air. Measurements were made using two methods: the impact method and the sedimentation method. For the assessment of microbiological air quality, the higher result of the number of bacteria or fungi calculated on the basis of the two air measurement methods was selected. The obtained results indicate the periodic occurrence of mannitol-positive and mannitol-negative Staphylococci in the tested air, which indicates a sanitary threat to students and employees staying in these rooms. It is essential to introduce air disinfection using UVC air-flow lamps, especially in teaching rooms.