How clean is airplane air, really?

EVERY TIME YOU CRAM INTO A TIGHTLY packed plane, you might find yourself wondering if you’re about to catch something from the person sitting next to you— or a few rows away.

- BY ALICE PARK

You're not alone: researchers are also curious about what’s lurking in airplane air. Erica Hartmann, associate professor in the department of civil and environmental engineering at Northwestern University, and her colleagues tried to find out by testing face masks worn by passengers on flights to document what kinds of bugs they trapped. The team was also interested in the air circulating in hospitals, another public place where germs commonly spread, and tested face masks worn by hospital personnel.

The researchers collected 53 masks in sterile bags and cut out the outer layers to analyze just the microbes circulating in the air, then extracted and analyzed DNA from them. To ensure they were detecting all the microbial DNA present, they also used an amplification process called PCR to enrich what was present on the masks.