Analysis of microbial contamination and risk assessment model construction at critical public congregation areas of apartment buildings

In the context of rapid urbanization, apartments have become the preferred living choice for many urban residents, bringing the microbial environment of public areas and its impact on residents' health into sharp focus. This study sampled airborne and settling microbes at key congregation points within apartment public areas, analyzed microbial community composition, and systematically assessed microbial risks during both static and dynamic stages. The results reveal that in the static phase, the airborne microbial population is dominated by Staphylococcus (740 CFU/m³), Lysinibacillus (650 CFU/m³), and Micrococcus (550 CFU/m³), while the settling microbial population is led by Staphylococcus (5658.8 CFU/(m²·h)), Micrococcus (4872.9 CFU/(m²·h)), and Lysinibacillus (2672.2 CFU/(m²·h)). The highest counts of airborne microbes were found in the stairwell (270 CFU/m³) during both phases, whereas settling microbes peaked at the apartment entrance (3615.4 CFU/(m²·h)) in the static phase and in the elevator car (15,247.4 CFU/(m²·h)) during the dynamic phase. Further biodiversity analysis results showed that the elevator car had higher diversity during both the morning and evening peaks in the dynamic phase, indicating that pedestrian flow significantly impacts the composition of the microbial community. A mathematical model was also developed to evaluate microbial hazards. The model reveals the elevator car having the highest microbial risk during dynamic phase, with an 18.2% higher risk in the evening peak compared to the morning. This study provides a scientific basis for microbial risk management, environmental design optimization, and disease prevention strategies in public areas of apartment buildings, which will help improve residents' living environment.