It is a known fact that we are surrounded by microbes wherever we go - be it indoors or outdoors. Now, a new research by Yale University engineers has revealed that a big ingredient in the microbial soup is our own microorganisms.
The mere presence of a person in a room can add 37 million bacteria to the air every hour, according to the study, which is the first to quantify how much a lone human presence affects the level of indoor biological aerosols.
The findings were arrived at after measuring and analyzing biological particles in a single, ground-floor university classroom when it was occupied and unoccupied.
"The floor dust turns out to be the major source of the bacteria that we breathe. Mostly people are re-suspending what's been deposited before", said Jordan Peccia, associate professor of environmental engineering at Yale and the principal investigator of the study.
About 18 percent of all bacterial emissions in the room, including both fresh and previously deposited bacteria, were contributed by humans. Four varieties of bacteria identified in the room studied were directly associated with humans, including the most abundant, Propionibacterineae, that inhabit human skin, said the researchers.
According to Peccia, carpeted rooms appear to retain particularly high amounts of microorganisms, but only less than 0.1 percent of the microorganisms commonly found indoors are infectious. Nevertheless, understanding the content and dynamics of indoor biological aerosols may help to implement new ways to improve air quality, he said.
The study was recently published online in the journal Indoor Air.
by RTT Staff Writer
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