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Travel Health & Safety: How Clean is Your Airplane's Air?

You have no choice but to breathe it, often for hours at a time. So what's keeping it safe most of the time, and how safe is it, really?

The old joke about certain foreign countries -- "Don't drink the water and don't breathe the air" -- is only partially true and in certain places at certain times. For the water, yes, lots of places and lots of times. For the air, think Beijing in winter, or Pasadena in summer for two locations to avoid. But you shouldn't have to say this about the air in airplanes. You have no choice but to breathe it, often for hours at a time. So what's keeping it safe most of the time, and how safe is it, really?

Altitude Attitude

Most planes these days pressurize their cabins at an assumed altitude of about 5,000 feet to 8,000 feet (1,500 to 2,500 meters), and Boeing says its new 787 cabin (due next year) will be set at a maximum of only 6,000 feet (1,829 meters, the level the supersonic Concorde kept), making for less headaches and other mild problems that are now associated with some flights, particularly long distance ones. Many people live and thrive at 8,000 feet and above (think La Paz in Bolivia or Lhasa in Tibet, for instance). But travelers with severe lung and heart problems, including anemia and sickle cell disease, may want to ensure that oxygen is on board in case of difficulty breathing. US Federal Aviation Agency rules allow only five kinds of manufactured oxygen to be brought on board, and in any case, you should check with the airline regarding its policy on this matter. If they forbid personal oxygen containers, you will have to purchase your oxygen from the airline, which may have it on some flights, not others. Give the airline two or three days of advance notice. A helpful website for those needing oxygen is

Odd as it may seem to most, passengers with recent abdominal or ocular surgery should consult their doctors before flying, as gases inside the body might expand due to cabin pressurization and cause unforeseen problems. In fact, everyone's intestines expand a bit as a result of pressurization, so digestion may be impaired. Carbohydrates may be easier to digest than meat, so choose the pasta course and have a salad if that is offered. Eat lightly and drink plenty of water is my motto most of the time.


The low humidity of airplane cabins dries out your airways and decreases whatever natural resistance you may have to infections. To make more profit, airlines have saved on fuel since the late 1980s by taking in less fresh air while aloft than they did on older planes, now taking in, at best, about 50% of what they used to, which was 100% fresh air. And they recirculate it after heating it, and so you are breathing in everyone's carbon dioxide over and over. While most city building codes demand that commercial office buildings bring in a minimum of 15 cubic feet of fresh air per minute, airplanes bring in as little as six to ten cubic feet, though pilots, who have to stay awake, get about 50 cubic feet per minute, one authority saying they get ten times as much oxygen as the passengers.

Most newer airplanes recirculate their air 20 to 30 times an hour, and have HEPA (high efficiency particulate air) filters, which capture 99.9% of particles, such as bacteria, fungi and bigger viruses) that measure between 0.1 and 0.3 microns, they say. Still, people appear to catch colds on airplanes.

You might consider an air ionizer, though critics insist they don't really do any good. My "evidence" is only anecdotal, applying only to me, but in my experience over the past eight years of using an ionizer, I believe my gadget, Air Supply, works. I don't believe it's just a coincidence that the number of plain old ordinary head colds I suffer after flying somewhere has dropped from about half the time to around a fourth of the time, a 50% decrease, so that's worth the effort, I believe. I use the Ultra-Miniature Air Supply, which costs $145 and is said by the manufacturer to be "the world's first wearable air purifier."


The air in plane cabins is so dry (usually 10% to 20% humidity, sometimes as little as 1%, compared to the Sahara desert's 20% to 25% humidity), that you health is challenged every time you fly. When you get dehydrated, your immune system is compromised and your entire body suffers in many different ways. Therefore, before boarding a plane, you must buy a bottle of water (or two) after clearing security, as flight attendants on most trips I have taken in the past six years do not serve water as often as before, nor are they usually as generous with the amounts. The days of being handed a full bottle of drinking water are mostly gone, at least in coach class (where I do most of my traveling). And on Third World planes, I get a little nervous about where the water comes from if it isn't in an unopened bottle.

During the flight, you should drink a full eight ounces (a big glass) of water for each hour you are in the air, minimum. I solve problems resulting from water drinking by sitting near the restrooms. Avoid caffeine and alcohol, which only dry out your body further.

Communicable Diseases Aloft

The CDC (Centers for Disease Control & Prevention) says it has only documented a single case of TB being transmitted from one passenger to another, this on a flight exceeding eight hours, pointing out that the number of air exchanges in an airplane exceeds the number recommended for hospital isolation rooms. A few rare cases of transmission of measles, flu and SARS have also occurred, and for colds, even, "the risk of transmission on airplanes may be small, if present." CDC, tel. 800/CDC-INFO, website, email


A fascinating and highly personal website concerned with air passenger health is that presented by Diana Fairechild, a former international chief purser for Pan American World Airways. She doesn't pull any punches, apparently. Check it out at

The next Travel Health & Safety column will deal with places where you can drink the water, and places not to.

Note: The author is also the Vice President (pro bono) of IAMAT, the International Association for Medical Assistance to Travellers, a registered charity, tel. 716/754-4883, website

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