SSS 2009-02-10（在线收听）

This is Scientific American's 60-Second Science. I'm Adam Hinterthuer. Got a minute?

Here’s a novel potential public health measure against the flu—kick up the humidity. The cold, dry months of winter signal the start of flu season. But previous research found only a weak correlation between the spike in flu rates and the drop in relative humidity. Now researchers from Oregon State University say that's because it's absolute, not relative, humidity that counts. Their study is in the February 9th edition of the Proceedings of the National Academy of Sciences.

Relative humidity is a function of temperature. During the dry winter, relative humidity is low in a warm house but high in the cold outside. Absolute humidity, however, is simply the total amount of water in the air. The less water in the air, the longer the flu virus survives. And that leads to a greater chance of someone catching the bug.

The scientists aren’t sure why humidity affects the flu virus survival. But they hope their discovery can be put to work. Emergency rooms and nursing homes, for example, could up their humidity during the winter. Maybe it’s time for a new health mantra: a sauna a day keeps the flu bug away.

Thanks for the minute for Scientific American's 60-Second Science. I'm Adam Hinterthuer.