Research finds that air contains bacteria!

In the quest for the ultimate environmental contamination paper comes one from Yale via Science Daily stating “A person's mere presence in a room can add 37 million bacteria to the air every hour.” Let that sink in—37 million bacteria EVERY HOUR! The story was picked up by several news organizations. Google “37 million Propionibacterineae” and see for yourself.

Before you reach for your gas mask and “boy-in-the-bubble” protective gear, let’s read on.

The researchers measured the air in a classroom at Yale, when it was both occupied and vacant. They found that "human occupancy was associated with substantially increased airborne concentrations" of bacteria and fungi of various sizes. [Insert your own “toxic air at Yale” joke here.]

Only 18% of the bacteria found came from humans with the most common being Propionibacterineae, skin organisms not generally considered pathogens.

Down at the end of the article is the disappointing news that “Extremely few of the microorganisms commonly found indoors—less than 0.1 percent—are infectious.”

But the study’s lead author is quoted, "All those infectious diseases we get, we get indoors." He pointed out that Americans spend more than 90 percent of their time inside.

If you want to learn more, the paper was published in Indoor Air, The International Journal of Indoor Environment and Health.

I’m going to pass on that and mention that I’ve written several blogs about this type of study. If you want to read them, click on the “Infection” label to your right. The point I make in these blogs is that many different environmental surfaces have been shown to harbor bacteria, but very few have been linked to outbreaks of disease.

I am happy to report that although contaminated with 37 million [!] bacteria per hour, air is still OK to breathe. This remains true even with people in the room.