An unchanging weather pattern over the Inland Northwest this week is trapping pollutants near the ground, creating air quality problems.
The stagnant conditions are keeping particles in the air from being thinned out or pushed away, said Jeremy Wolf, a meteorologist with the National Weather Service office that serves the Spokane area.
“When we see a prolonged period of limited mixing in the atmosphere, we just don’t have enough air movement to disperse a lot of the lower-level pollutants up into the atmosphere,” Wolf said. “So when we get several days of this type of condition, then we can see a build-up of pollutants.”
Air quality warnings in the summer and early fall, prompted by copious wildfire smoke, have become familiar in the Inland Northwest. This week’s poor air quality is different in that it contains less wildfire smoke, and has higher proportions of pollution from vehicles and from intentional burning, such as fireplaces, wood stoves and outdoor waste or brush piles.
The air stagnation advisory lasts until at least 11:00 a.m. Thursday. While a weak storm system is forecast to approach the area late in the workweek, Wolf said, air quality is not expected to improve much until the weekend.
“We see a stronger storm [in computer modeling] as we enter this weekend, and that is expected to clear out the air,” Wolf said.
Lisa Woodard, communications and outreach manager for the Spokane Clean Air Agency, said Monday that air quality was expected to get worse as the week unfolds, but not to the levels seen in wildfire season.
Each morning, an air quality forecaster checks on conditions. If things get considerably worse, Woodard said, the Clean Air Agency can issue temporary restrictions on wood heating and outdoor burning until the weather becomes more favorable.
“We haven’t gotten to that point yet, but that’s a tool in our toolbox to keep air quality within the health-based standards,” Woodard said.
Even without formal restrictions, Woodard said people living in eastern Washington and north Idaho should check conditions each day and prepare to change their routines in the interest of protecting their health.
“If the air quality is above moderate, then take some steps for your personal health condition,” Woodard said. “For example, you may not want to be taking your brisk morning or evening walk. You may want to limit that activity if you’re in a health-sensitive group.”
Residents can check air quality websites to find out what to expect before going outdoors.
Air quality readings across the Inland Northwest were in the “good” to “moderate” range Monday, with a few stations near the Kootenai/Spokane county border reporting levels considered “unhealthy for sensitive groups.”
