A layer of air rests over the Umpqua Valley near Garden Valley Boulevard on Tuesday.

Air quality in the inland valleys of Southern Oregon will deteriorate over the next several days, according to the National Weather Service

The weather service has issued an air stagnation advisory that will remain in effect until Monday at 10 a.m. but it could go longer than that.

“It’s more like a 10-day event, but I wouldn’t be surprised to see it go two weeks,” said Frederic Bunnag, a meteorologist with the National Weather Service in Medford.

A large high-pressure system all the way from British Columbia into Southern California has caused the atmosphere to become very stable so there is very little movement in the air, Bunnag said.

He said the air stagnation advisory indicates that due to limited movement of the air mass across the area, pollution will increase, and the air quality will deteriorate due to the extended period of stagnant air.

“So if you put any smoke or particulates into the atmosphere, it’s going to hang around,” he said.

Dr. Bob Dannenhoffer, the Douglas County public health administrator, said the prolonged stagnant air could present health problems for some in the county and those at risk should avoid the outside air when it becomes unhealthy.

“We especially worry about those who have chronic respiratory illness or for people who have other underlying lung diseases like lung cancer or COPD,” Dannenhoffer said. “In those cases, we recommend they not be out when the air is unhealthy.”

He said it’s not unhealthy yet, but the risk is there the longer the stagnation continues.

The air stagnation normally happens during cold temperatures at the same time when more people want to use wood stoves for heating. But the smoke will contribute to the pollution.

“We recommend for people that do not have to burn in wood stoves and fireplaces, not to burn during this time if you can avoid it,” Dannenhoffer said.

There is likely to be fog off and on, associated with the stagnant air. The stable atmosphere promotes high humidity and the moisture clings onto the particulates in the air, and Bunnag said that helps form the fog.

Possible freezing temperatures could result in freezing fog, leading to some treacherous driving. Motorists will need to be aware of possible ice on the roadways in many areas of the county through Sunday night, before temperatures are expected to warm early next week.

Reporter Dan Bain can be reached at 541-957-4221 or e-mail at dbain@nrtoday.com.

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Dan Bain is the health reporter for The News-Review. He previously worked at KPIC and 541 Radio.

(2) comments


In the caption to the photo, I believe you left out the word "stagnant." It would read better if it said, "A layer of STAGNANT air..." (would keep folks like me from laughing uproariously and pointing out that there is a layer of air above and below that cloud as well!).



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