Investigation of environmental sanitary conditions in waiting rooms of hospitals in Fengtai District, Beijing, China, 2018—2023

Objective  To investigate the indoor air quality and the sanitary conditions of central air conditioning ventilation systems in waiting rooms of hospitals in Fengtai District, Beijing, China, and to provide a basis for improving the environmental sanitary conditions in waiting rooms.

Methods  From 2018 to 2023, a total of 120 monitoring sessions were conducted to assess indoor air quality and central air conditioning ventilation systems of 35 hospitals in Fengtai District. According to the Examination Methods for Public Places (GB/T 18204-2013), on-site measurements were conducted to assess indoor temperature, relative humidity, indoor air velocity, carbon dioxide, and inhalable particles in the supply air. Samples were collected from the supply air of central air conditioning, the inner surface of ducts, and the cooling water of cooling towers. The samples were sent to laboratory for measurements of total bacterial count, total fungal count, β-hemolytic streptococcus, dust accumulation, and Legionella pneumophila.

Results  From 2018 to 2023, the overall qualified rate for environmental sanitary conditions in waiting rooms of hospitals in Fengtai District was 72.33%. The overall qualified rate for indoor air quality was 60.10%. Seasonal variations were observed in indoor air quality indicators. The qualified rates for indoor temperature, relative humidity, and carbon dioxide were lower in winter and spring compared to summer and autumn (χ²=14.59, 68.92, and 19.20, respectively, P≤0.001). The overall qualified rate for the central air conditioning ventilation systems was 87.35%. There were significant differences in the qualified rates for different indicators in the monitoring of air conditioning systems (χ²=158.51, P < 0.001). The lowest qualified rate was observed for total bacterial count in the supply air (36.78%), followed by fresh air volume in the air conditioning system (60.71%). The detection rate of Legionella pneumophila in cooling water was 4.17%, the dominant strain was LP1, and positive detections concentrated in July. After the COVID-19, the qualified rate of indoor air quality and the overall qualified rate were significantly improved (χ²=59.81 and 7.97, respectively, P < 0.05).

Conclusion  The environmental sanitary conditions were suboptimal in the waiting rooms of hospitals in Fengtai District. The main problems of indoor air quality included excessive carbon dioxide and high bacterial counts in the air, as well as low qualified rates for thermal comfort indicators such as indoor temperature and relative humidity. The main problems in central air conditioning ventilation systems were excessive microbial counts in the supply air and Legionella pneumophila contamination in the cooling towers. The monitoring and management of the indoor air quality and the sanitary conditions of central air conditioning ventilation systems in waiting rooms of hospitals should be strengthened in the future.