‘Air Stagnation Advisory’ in Effect until Friday in Missoula

The National Weather Service, in conjunction with the Missoula City County Health Department has declared that an Air Stagnation Advisory is now in effect in the Missoula valley.

Air Quality Specialist Ben Schmidt has details.

“That's a service that the National Weather Service now provides, and they have for the last two years, where they alert people in our mountainous terrain when we could have Valley inversion,” said Schmidt. “Of course, when you have valley inversions, that's where you have pockets of cold air just sitting there and everything it generates down there does all that it a little bowl of cold air because the cold air doesn't rise and clear out.”

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Schmidt explained further.

“So what's going on is, a high pressure ridge has moved in, it could weaken in the middle of the week, it could come back; it’s a little iffy exactly what's going to go on,” he said. “But that air stagnation alert is just trying to let people know to do things to try to reduce your emissions as much as possible,” he said. “That way we won't get elevated particulate levels in the air, which of course has health consequences for people.”

Schmidt detailed the ways residents can help mitigate the pollution that stays in the Missoula valley.

“So the basic things people can do to reduce pollution in the valleys is, number one, if you do have a solid fuel burning device such as a fireplace or wood stove is do not use it when we have an air advisory or high pressure ridge in the area,” he said. “It is really that smoke you generate has nowhere to go. It just sits here and affects you and your neighbors.”

Schmidt said anything you can do to reduce your driving during an Air Stagnation Advisory will also help to mitigate the pollution.

“The other thing people can do, especially when we're in this advisory in these freezing temperatures in that 30 to 32 degree range is reduce your driving,” he said. “Trip chain, combine trips, find ways to reduce your emissions from your vehicles whether it's a diesel or gasoline engine, which is more common. You do have noxious emissions from your vehicles, which can combine in the atmosphere to form ammonium nitrate that is one of the pollutants that can get elevated in the Missoula Valley during these inversions, and the automobile is the primary source for that.”

The alert is in effect through 5:00 p.m. on Friday.