Breathing Life in the Subway

 Hong Kong MTR network map
Courtesy of: Leung, Wilkins, Li, Kong, and Lee (2014)

Few people recognize the amount of life found in the twisting tunnels of a subway, but Leung, M.H.Y. et al. have recognized the importance of determining what types of microbes travel through the air that many commuters in dense cities breath daily in their lives. They tested seven train tracks, collecting the aerosolized microbes during morning peak and non peak hours, as well as during evening peak and non peak hours, over 15 regular weather days. Their study showed that the majority of microbes found in subway were associated with skin, and that the communities within the subway differed based on the architectural characteristics, nearby outdoor micro-biomes, and connectedness with other lines. So, in general while riding the subway keep in mind that you are constantly breathing in a variety of microbial life and that the temperature, humidity and carbon dioxide levels lead to increased abundances of aerosolized microbes. 

So, maybe you should consider walking or riding a bike once in awhile?

Reference: Leung, M.H.Y., Wilkins, D., Li, E.K.T., Kong, F.K.F., and P.K.H. Lee. (2014) Indoor-air microbiome in an urban subway network: diversity and dynamics. Applied and Environmental Microbiology 80(21):6760-6770.