Objectives To investigate and analyze the circumstances of air quality in Guangzhou Metro Line 5 station to provide scientific evidence and reasonable suggestion for health management and disease prevention of metro.

Methods 24 stations of Guangzhou Metro Line 5 were monitored with each monitored on 5 points at the platform and concourse respectively. The monitoring indexes included air temperature, relative humidity, wind velocity, illuminance, noise, carbon monoxide(CO), carbon dioxide(CO₂), respirable particulate matter(PM₁₀), formaldehyde, the total count of bacteria colony.

Results Average noise value of 21 stations exceeds the national standard, with the unqualified rate 87.50%. Average formaldehyde value of 3 stations was higher than the national standard, with the unqualified rate 12.50%. The concertration of CO₂ at the platform was higher than those at the concourse, while relative humidity, PM₁₀ and illuminance at the platform were lower than those at the concourse(P < 0.05).The concertration of CO₂, formaldehyde, the total count of bacteria colony at the transfer stations was higher than those at the untransfer stations, while wind velocity at the transfer stations were lower than these at the un-transfer stations(P < 0.05). The temperature, CO, PM₁₀ at the elevated stations was higher than these at the concourse, while CO₂, formaldehyde at the elevated stations were lower than those at the concourse(P < 0.05).

Conclusions The noise and concentration of formaldehyde should be stressed as more important index for assessing the air quality in metro. The transfer stations were punctuated as to improve the air quality. The air quality in the subway stations could be better by strengthening fresh air supplement and filtration.