by Dana Wollman on March 27, 2009
Unless you fly business class—and even then there are no guarantees—it’s near-impossible to leave a plane feeling well rested. Your neck will remain frozen at a 90-degree angle, your ears will need popping, your clothes will be rumpled, and dehydration is par for the course (hunger, too, if you opted not to pay for an in-flight snack).
But more than the discomfort, the common assumption about planes is that they’re unclean. Researchers know these vessels harbor more bacteria than places on the ground (even airports). But no one can prove that flying makes people more susceptible to diseases, much less which ones. So should you worry? And what can you do to stay healthy?
The question of whether or not people are more likely to fall ill when they fly has been the holy grail for industrial hygiene researchers. After all, it’s tough to determine whether a person caught something on the plane, or earlier that week while dropping the kids off at day care. “To prove you were exposed to that particular virus on a particular aircraft is difficult,” said Lauralynn McKernan, ScD, a research industrial hygienist at the National Institute for Occupational and Safety Health (NIOSH).
Add to that loss of sleep, time zone changes, dehydration, and other factors that scientists know hurt our immune systems, and you’ve got yourself a hypothesis that sounds like common sense, but is almost impossible to prove.
Not all scientists even agree on whether or not airplanes are “germier.” Dr. McKernan recently led a study concluding that the air quality on planes isn’t necessarily worse than what you’d breathe on the ground; her team found that the concentration of fungi was similar, though detected less frequently, to what you’d find in an office building (or the terminal of an airport). The bacteria they found—Micrococcus luteus, Bacillus, and Staphylococcus (that’s Staph, for short), and gram negative bacteria—are commonly found on skin, among other organisms common in dust and outdoor air.
Dr. McKernan, however, did find that the 12 planes she tested had the highest concentrations of these organisms when passengers were boarding and disembarking. She thinks that’s partly because people stand closer to each other during those times and are moving around more, but also that when the plane is on the ground it uses an auxiliary ventilation system. In other words, you can joke all you want about the recycled air on planes, but the ventilation system seems to work effectively.
These findings, Dr. McKernan explained, could serve as a hint to disease-transmission researchers. “Maybe they should focus disease-prevention efforts on the time period before air is captured into the filtration system,” she mused.