Seasonal variation and influencing factors of airborne bacterial and fungal concentrations in different indoor public environments

Airborne microorganisms in diverse building types pose distinct hazards to human health. Thus, it is essential to determine the distribution of indoor microorganisms in public spaces. This study investigated airborne microorganisms in three public places (n = 277 rooms). The results revealed significant differences in microbial concentrations among various public places. The microbial concentrations in supermarkets (Bacteria: 732.16 ± 1354.82 CFU/m³, Fungi: 440.52 ± 555.97 CFU/m³) were higher than those in hotels (Bacteria: 240.86 ± 361.30 CFU/m³, Fungi: 244.16 ± 377.85 CFU/m³) and waiting rooms (Bacteria: 206.24 ± 256.82 CFU/m³, Fungi: 266.81 ± 349.02 CFU/m³). The results indicate that low temperatures and high air exchange rates can reduce the indoor airborne microbial concentration. Moreover, PM10 also affects the concentration of airborne microorganisms. This study provides practical significance for evaluating the distribution of microorganisms in different buildings and valuable data for developing indoor microbial standards.