A cold air inversion concentrated east of the Cascades is keeping the air clogged with tiny particles. And public health officials in Washington, Oregon, and Idaho warn that people trying to warm up in front of wood fires could make the pollution worse.
Here's what's going on in the atmosphere: Usually, air temperature decreases as you get higher. But in an air inversion, the opposite happens. And the warmer air acts like a lid, keeping particles concentrated near the surface.
Judy Bardin is an epidemiologist with the Washington Department of Health. She says the people who are most vulnerable to smoke pollution are children and people with lung and heart issues.
But healthy adults shouldn't consider themselves immune.
"The level of activity that may cause problems is different for people," Bardin explains. "You know if they have asthma, it could be taking the dog out for a walk. Or somebody else may not have problems until they go out for a run."
The National Weather Service has placed parts of southern Oregon, eastern Oregon and Washington, and north Idaho under a stagnant air advisory. Health agencies urge against idling cars and cozying up to a fire unless absolutely necessary. Outright burn bans are effect in Spokane, the Yakima Valley, and other areas of eastern Washington.
Forecasters say the health advisory may last longer than they originally thought.
As one Washington Department of Ecology spokesman said, "it's still up in the air."
On the Web:
National Weather Service warnings:
http://www.nws.noaa.gov/view/nationalwarnings.php?map=on
Airwatch Northwest:
Copyright 2011 Northwest News Network
Copyright 2011 Northwest News Network
