Characterization of Microbial Aerosol Contamination in Public Spaces and Health Risk Assessment:A Case Study Based on Campus Buildings

WANG Wei; WU Shan; WU Junqi; HE Yanting

doi:10.3969/j.issn.1000-0232.2025.07.005

Abstract：To address PM2.5 microbial aerosol contamination in the indoor environments of university campus public buildings,this study systematically analyzed the characteristics of microbial aerosol contamination and relevant health risks in teaching buildings,dormitories,and cafeterias using an interdisciplinary methodology.By combining an exposure evaluation model with microbial sampling,environmental factor monitoring,and 16S rRNA sequencing technology,the coupling relationships of spatial morphology,environmental parameters,and microbial community in these buildings were disclosed. Research results revealed that indoor PM2.5 concentration was generally lower than outdoor concentrations,but showed significant differences in spatial distribution.The atrium-style vertical space in teaching buildings reduced PM2.5 concentrations by 20％～30％due to thermal buoyancy-driven ventilation.Conversely,horizontally-confined zones like dormitory corridors and cafeteria dining aisles become key pollution sites due to airflow obstruction,with peak PM2.5 concentration reaching 1.5 times that of open areas.Microflora analysis showed Proteobacteria,Bacteroidota and Firmicutes as dominant bacterial communities,with Stenotrophomonas accounting for a relatively high proportion in teaching buildings,dormitories,and cafeterias.Notably,microbial abundance in dormitory corridors was significantly higher than in other functional zones,while the relative abundance of Acinetobacter in dining areas was 30％～60％higher than in other areas,likely due to dining activities promoting microbial diffusion. Analysis of the environmental driven mechanism indicted that microflora in different building types showed varying responses to environmental factors.Regarding relative microbial abundance,it correlated with PM2.5 concentration,temperature,and humidity,with PM2.5 concentration specifically showing a positive relationship.For microflora structure,PM2.5 and humidity affected microflora structures both inside and outside teaching buildings,and significantly influenced those in dormitories.In dining areas,temperature predominantly controlled microflora distribution.This difference reflected the selective construction of microbial ecological niches based on architectural functional zoning.Health risk assessments identified potential risks in dormitory corridors(HQ=0.151),bathing areas(HQ=0.148),and dining areas(HQ=0.167).The cumulative exposure risks for male workers were about 1.40 times that of female workers,primarily attributed to differences in years of occupational exposure. Based on these findings,the study revealed the spatial-environmental coupling mechanism of PM2.5 microbial aerosol,offering a new perspective for the healthy design of campus buildings.Proposed spatial optimization strategies include:adopting a layout combining vertical ventilation and horizontal flow guidance;optimizing dormitory corridor width to 2.2m to improve pollutant emission efficiency;and setting a misaligned layout of bathroom entrances and corridor axes(≥30 ° deflection)while increasing window areas at both ends of the corridor.Regarding management strategies,dynamic ventilation regulation was implemented in high-risk areas.For example,ventilation rates were increases to ≥ 4 times/hour during dining hall peak hours,and dormitory directional ventilation systems were turned on during bathing hours(20:00-22:00),simultaneously controlling humidity(RH＜65％)and microbial diffusion. This study not only deepens understanding of microbial aerosol contamination in campus buildings but also provides scientific references for controlling health risks in public buildings.It holds significant theoretical value and practice importance.Future studies can further quantify the interaction effect between pedestrian dynamics and static building structures to refine prediction models and control systems.