Investigation on indoor air sanitary conditions during trial operation of the newly-bulit metro line in Taiyuan, China

Objective To monitor and evaluate the sanitary conditions of indoor air before operation of the newly-built metro line in Taiyuan, and provide basis and suggestions for the sanitary management after the metro line formal operation.

Methods From November to December in 2020, total number of bacteria, formaldehyde, ammonia, benzene, toluene, xylene, ozone, carbon monoxide, carbon dioxide, inhalable particles, radon and its decay products were measured during the trail operation of the newly-built metro line in Taiyuan according to the Examination Method for Public Places(GB/T 18204), the Specifications for Monitoring of Indoor Radon and Its Decay Products (GBZ/T 182-2006).

Results A qualified rate of 100% was observed for total number of bacteria, formaldehyde, ammonia, benzene, toluene, xylene, ozone, carbon monoxide, carbon dioxide, inhalable particles, radon and its decay products in the air of the stations halls and platforms in 23 stations, but the temperature could not meet the health limit requirements of public places. There were no significant differences in the total number of bacteria and the concentrations of radon and its decay products between the transfer stations and the non-transfer stations, and between the hall and the platform; there were no significant differences in the concentrations of radon and its decay products between the stations with different degrees of decoration.

Conclusion During the trial operation of Taiyuan Metro, the indoor air sanitation of 23 stations was good. Relevant departments should continue to strengthen health management and monitoring before the official operation of the metro to ensure the health of the public travelling in the metro line.