Every winter, legions of healthy travelers board airplanes wondering if they’ll still be well when they walk off, after spending hours packed shoulder to shoulder with dozens—or even hundreds—of other passengers, some of whom are likely to be suffering from a cold or the flu. This year, the prospect of contracting swine flu has of course heightened the anxiety. But there’s good reason to take heart (and take to the skies): Several scientific studies show that, in terms of the spread of contagious bugs, airplanes are healthier environments than is commonly believed.
While it’s true that the germs which cause colds and flu can be passed from person to person through coughs and sneezes, research indicates that you need to be sitting very close to a sick passenger—usually within two rows—and for longer than eight hours to significantly increase your chances of contracting an illness. “There is a heightened risk of infection when you enter a confined space such as an aircraft or subway, but a plane is a much safer place because of the ventilation system,” says Dr. Mark Gendreau, an emergency and aviation medicine expert at the Lahey Clinic in Burlington, Massachusetts.
On average, cabin air is completely refreshed 20 times per hour, compared with just 12 times per hour in an office building. On most aircraft, air is also circulated through hospital-grade HEPA filters, which remove 99.97 percent of bacteria, as well as the airborne particles that viruses use for transport (many regional jets lack these filters). Additionally, cabins are divided into separate ventilation sections about every seven rows of seats, which means that you share air only with those in your immediate environment and not with the guy who’s coughing up a lung ten rows back. When the plane is on the ground, however, air circulation in the cabin can be greatly reduced.
The most common way to pick up a bug when flying, experts say, is from a contaminated surface—tray tables, lavatory doors, and latches on overhead bins are loaded with viruses and bacteria. “When I travel, I become very compulsive and even wipe the tray table with an alcohol-based hand sanitizer,” says Dr. Gendreau.
The achy, icky feeling many fliers get after spending hours in the air usually has nothing to do with colds or flu and everything to do with the bone-dry, oxygen-thin atmosphere of the cabin. But new developments in aircraft manufacturing and air filtration promise to make flying more comfortable and to reduce even further the chance that you’ll catch something from a fellow passenger.
The next generation of planes will be built from composite materials—plastics reinforced with carbon fiber—offering relief not only from altitude sickness but also from the burning eyes and swollen nasal passages many fliers experience. Both the Boeing 787 Dreamliner and the Airbus A350, which will launch in a few years, will usher in a new era of comfort with more humidity and less pressure than current planes.
The latest development in cabin air quality is AirManager, a new purification technology being tested by British aerospace giant BAE Systems. It uses a patented technology known as “non-thermal plasma” to eliminate not only germs and particles but also all the viruses, impurities, and foul odors that HEPA filters cannot.
How does cabin air flow?
Here's how cabin air is circulated, filtered, and refreshed throughout most of today's aircraft:
1. Fresh air continuously enters both engines at -65 degrees. Temperature and pressure are increased, then air is passed through a control valve and cooled by additional outside air.
2. HEPA filters remove 99.7 percent of particles; new technology could destroy 100 percent of all bacteria and viruses.
3. Filtered, recirculated cabin air and fresh air are combined.
4. The aircraft is divided into ventilation segments of three to seven rows; you share air only with passengers in your segment.
5. Outflow valve continuously releases cabin air and helps maintain constant pressurization of aircraft.