Air Passengers Very Likely to Catch Colds

Researchers at Canada's University of Victoria discovered that air travelers are much more likely to catch a cold after flying, than if they had not taken their flight. Apparently the chance of infection is increased not so much by air recirculation as air humidity -- very low air humidity. A portion of this very interesting post at The Citizen Scientist:

Very dry air dries up the mucous system that captures and expels bacteria and viruses from our noses. This may be a key reason why airplane passengers catch more colds.

Experiments to add humidity to airplane air have not been very successful, at least so far. The passengers themselves add some humidity simply by breathing. But it’s common for the relative humidity on an airplane to be ten percent or less.

Some passengers have devised clever ways to keep their personal air humidified. A few wear face masks, which adds humidity to the air being inhaled. But face masks can disturb fellow passengers. (This bias will change if a flu pandemic occurs.)