Is the air on planes full of germs?

That little air blower above your seat is often a welcome relief on a long flight, but the thought of breathing “recirculated air” may make you a bit queasy… After all, you’re with a large group of people in a confined space, all sharing the same air – germs and all. The reality is, it’s not all recirculated, and it’s nearly germ-free.

Modern passenger planes draw air from outside, through the engines, which is then mixed with cabin air. So you are always breathing a mixture of fresh and recirculated air. The recycled cabin air is run through hospital-quality High Efficient Particulate Air (HEPA) filters that remove 99.9% of germs and contaminants. Furthermore, some air is released as fresh air is brought in. The average plane’s cabin air is completely replaced 20 times per hour. Finally, since the filtration system circulates air from floor to ceiling (as opposed to front-to-back of the plane), any shared germs would be only from those passengers that are already in your immediate vicinity. In summary, the germy airplane air that people fear is probably cleaner than you would breathe in your home, office building or the hotel you check into after you land.

While airbone germs are not a worry, there is one legitimate concern about air quality: humidity. Cabin air is particularly dry, averaging only 12% humidity – lower than most deserts! Humidifying systems are impractical – the water required would be too heavy for the plane to carry, and the extra moisture in the air would hasten corrosion of the airplane’s metal parts. So, drink lots of water when you fly to stay hydrated, but you can leave the breathing mask at home.