Every time she boards an airplane, Sheelagh Doyle of New York City worries that the dry, recirculated air onboard will make her sick.
“Most times, when I take a flight over a few hours, I get a cold or chest infection,” she said. “I’ve resorted to hiding under a blanket for long-haul flights trying to avoid it.”
Many travelers who fall ill within a day or two of a recent flight blame the quality of the cabin air. But as it turns out, airplane air is no worse than what you'd encounter in your average office building.
It's that coughing or sneezing seatmate that you need to worry about.
“Airplane air isn’t as bad as most people envision,” said Charles Gerba, an environmental microbiologist at the University of Arizona at Tucson. Gerba, also known as Dr. Germ, studies germs and where they congregate and doesn’t worry much about the air quality on airplanes. “On a trip, it’s more likely that the food you eat and the things you touch will make you sick.”
The air up there
Many passengers mistakenly believe that the air in the cabin that they left the gate with is the air they have to breathe for the rest of the trip. “This is not true,” said Boeing spokesperson Bret Jensen.
He blames low humidity for giving airplane air a bad rap. “The overall relative humidity aboard an aluminum airplane is low — around 6 percent — and people become dehydrated on long flights if they don't drink water regularly. This can make people feel different than when they boarded the airplane.”
Modern airplanes do recirculate air, “but don’t let that scare you,” said travel health expert Mark Gendreau, the senior staff physician and vice chair of emergency medicine at Lahey Clinic in Burlington, Mass.
“Airplanes take about 50 percent of the air collected in the outtake valves of the passenger compartment and mix it with fresh air from outside that gets heated by the engines. That air is then passed through HEPA filters that sterilize it before it’s reintroduced to the passenger cabin.”
Previously, some health experts were concerned that airlines might not service those HEPA filters as often as they should. But Gendreau says both health and economic concerns help insure that airlines do. “If HEPA filters age, they start collecting material. That creates drag and airplanes start burning more fuel. And these days airlines are not interested in wasting fuel.”
It may help you breathe easier next time you fly knowing that air flow is minimized between seat rows and that airplane air is refreshed more often than the air in office buildings.
“You are closer to people in the enclosed space of an airplane than you are in an office building,” Gendreau said. “But something called ‘dilution ventilation’ means that even with microorganisms in an air space, if you have good ventilation, there will be less of a chance of transmission.”
The airborne germs on an airplane to be wary of, say both Gendreau and Gerba, are the ones coming from an ill traveler in a row nearby.
“When someone coughs or sneezes, 20 to 30,000 particles fly out about three feet and settle on nearby surfaces. Those microorganisms can live from several minutes up to 24 hours,” said Gendreau. “If you’re more than six feet away from that person, you don’t have much to fear. It won’t propel far enough.”
But if you touch something that a sick passenger's germs have landed on, you’re at risk.
Watch what you touch
Travel health experts say that instead of worrying about the cabin air, travelers should make an effort to avoid touching objects such as airplane toilet seats, soap dispensers, seatbacks, armrests and especially tray tables that can harbor infectious germs. “There are surfaces that everyone touches and you have no idea if a person has sniffles and then walks down the aisle touching the seats and armrests as they go,” said Gendreau.
“We find a lot of flu and cold germs on airplane tray tables,” said environmental biologist Gerba, who takes test swabs during his frequent travels. “And there’s no protocol or government requirement for airlines to clean those between flights.”
And don’t think that all the germs you encounter when traveling are on an airplane. “Think about all the places you can get exposed to an illness from the time you leave home,” said Gendreau. “You park in a garage, take the escalator and touch the hand rest. You touch the buttons on the ATM. You go through the security checkpoint, you buy coffee, you sit on a seat. Any of these surfaces might be contaminated.”
To steer clear of germs on airplanes, Gerba suggests trying to avoid sitting next to someone with a cold and even asking to be moved away from a sneezer if there’s an open seat.
If you can’t change your seat, Gendreau said, try turning the air vent above your seat to medium flow and pointing the air current just slightly in front of your face so that germs from those coughing or sneezing nearby are deflected away from you.
He also urges travelers to stay hydrated. “Our nasal passages, our eyes, and the mucous membranes in lips and mouths have enzymes to fight bacteria,” he said. “If you’re dehydrated, those enzymes won’t work well.” Gendreau suggest drinking at least 8 ounces of water for every two hours.
Mostly, though, keep your hands clean.
“Airlines do minimal cleaning of the airplanes during the day,” said Gendreau. “So when I travel, after I put my stuff in the overhead bin, I’ll take out my hand sanitizer, put some drops on the tray table and clean it with a tissue. I’ll also clean the seat belt and the armrests and goop up my hands. Then I know my seat area is sanitized.”
And then he sits back, relaxes and takes a deep breath.