Hold Your Breath - Airline Air Explained.
-- Frank Gillingham, MD

Air travel is extremely safe, but as most of us who fly frequently know you can end up pretty uncomfortable on even a short flight. Many frequent flyers complain about the air quality and with good reason:

• Airline cabin air is recycled. Older aircraft tend to filter air and mix in part fresh air before recirculating it in the cabin. Newer aircraft tend to use almost all recirculated air. Often when the plane is on the ground the recirculation and filtering systems aren't completely functional so the air may be of even worse quality than when you're inflight.
• Airline cabin air is extremely low in humidity. Such air can dry the mucous membranes of your nose, mouth, throat and bronchial tree (or breathing tubes), which are then less able to keep out viruses and bacteria. Your eyes may become dry and uncomfortable as well.
• Airline cabin air is low in oxygen relative to fresh air on the ground. Healthy individuals shouldn't notice any difference but those with chronic lung conditions might
• While airplane filtration systems are pretty good at eliminating more serious pathogens like Tuberculosis (TB) from cabin air, the proximity of your fellow passengers can increase your risk of getting a respiratory infection--a miserable, business trip-spoiling cold.
• Smoking -- banned from U.S. Domestic flights and international flights to and from the U.S., still occurs on some domestic flights in other countries. Smoke increases mucous membrane irritation, exacerbates lung conditions like asthma and generally makes flying even more uncomfortable than usual.

Here's some advice on coping with airline air:

• Stay well hydrated by drinking lots of fluids (water or fruit juice) and avoiding caffeine and alcohol, which will dehydrate you. In my experience most flight attendants will gladly provide you a bottle of water even during the boarding process. Take out your contact lenses before you fly--or have your lens case handy in case you need to take them out in-flight.
• If your row-mate has chosen to fly with a raging cold and is sneezing and coughing near you, ask to be reseated. Cover your nose and mouth when he or she sneezes.
• Wash your hands. Many respiratory viruses are transmitted through hand to face contact. In addition to keeping your hands clean, don't touch your mouth, nose or eyes with dirty fingers.
• If you're traveling internationally check the HTH Worldwide airline smoking policy listing below. If you're taking a trip with multiple legs that perhaps requires you to fly on a smaller airline for part of your trip, check with that airline directly. If smoking is allowed on any of your scheduled legs, you might want to re-route your trip (if possible).
• Plan ahead--If a cold or illness would ruin a critical business meeting, make sure you bring along the cold remedies you rely on at home. Or check CityHealth Profiles for information on pharmacies at your destination--and even for the name of a doctor in case you really end up really uncomfortable or sick. Remember, that big, reliable chain pharmacy you can count on for 24 hour/day service at home doesn't exist in your destination country. And your favorite remedy may not be sold there or may be sold under a different name.
• If you have a chronic lung condition or if your immune system is compromised because of illness or treatments such as chemotherapy, be sure to check with your doctor prior to flying. Regardless of the status of your health, it's always a good idea to check in on a regular basis with an internist, family medicine specialist, or other primary care physician you trust.