Objective To investigate the current status of indoor microbial pollution in waiting rooms of train and intercity bus station, and to explore the main influencing factors for microbial pollution in indoor air and on object surface in station waiting rooms.

Methods The monitoring data of 177 intercity bus station waiting rooms and 89 train station waiting rooms were collected from the National Public Place Health Risk Factor Surveillance Program in 2021. Mann-Whitney U test and chi-square test were used to compare differences of the total number of airborne bacterial colonies, the total number of airborne fungi, the total number of surface bacterial colonies and the unqualified rates among different groups. A logistic regression model was used to analyze the main influencing factors for indoor microbial pollution.

Results In bus stations, the total number of airborne bacterial colonies and its unqualified rate were lower in South China than that in North China, and the unqualified rates of the total number of airborne fungi and armrest-surface total number of bacterial colonies were higher in South China than that in North China. In train stations, the total number of airborne fungi and its unqualified rate were higher in South China than that in North China (P < 0.05). Seasonal differences were not observed in the total number of airborne bacterial colonies, the total number of airborne fungi and the total number of bacterial colonies on object surface in bus and train waiting rooms. Multivariate logistic regression analysis result showed that the total number of airborne fungi in the waiting room and the total number of bacterial colonies on the seat armrest were positively associated with temperature and relative humidity in bus stations, and the odds ratios with 95% confidence intervals were 1.05 (1.01-1.10) and 1.03 (1.02-1.06), 1.10 (1.03-1.17) and 1.02 (1.01-1.04), respectively. The total number of airborne fungi was positively associated with relative humidity in the waiting room of train stations, and the odds ratio with 95% confidence interval was 1.04 (1.02-1.07).

Conclusion There are great differences between North China and South China in the level of airborne microbial pollution at bus and train station waiting rooms, and higher airborne microbial colonies are associated with higher temperature and relative humidity.