MONDAY, April 29 (HealthDay News) -- The population of microbes
in the air of the New York City subway system is nearly identical
to that of the air on city streets, according to a new study.
Along with showing the efficiency of the subway system's
ventilation system, the findings provide an important baseline in
case air in the system needs to be checked for the spread of
potentially dangerous microbes, the researchers said.
The research team used a new high-tech device to collect air at
a rate of about 300 liters per minute. Within 20 minutes, the
researchers had a sufficient amount of air to conduct a census of
the microbe population.
The study is published online in the journal
Applied and Environmental Microbiology.
The findings "are strong testimony for the efficiency of the
train pumping system for ventilation," principal investigator
Norman Pace, of the University of Colorado, Boulder, said in a
journal news release.
The only obvious differences between air on the street and in
the subway is that the subway's population of microbes has a
somewhat higher proportion of skin microbiota and twice the density
of fungal microbes, which Pace said may be due to rotting wood.
"I was impressed by the similarity of [subway] and outdoor air," he said.
Until now, there was nothing known about the microbe population
of subway air, Pace said. He added that the microbiology of indoor
air is a growing area of research as scientists try to understand
how these complex microbial ecosystems affect health and the
Some day this knowledge will influence design and construction
practices, said Paula Olsiewski, program director at the Alfred P.
Sloan Foundation, which funded the research.
The U.S. Environmental Protection Agency offers an overview of