SPOKANE, Wash. — Since Saturday, the Air Quality Index in Spokane has varied between Moderate and Unhealthy primarily as a direct result of the Williams Flats Fire. But different parts of the city can experience different air quality levels at the same time.
Spokane Regional Clean Air Agency is our primary source for reporting air quality. There are four sites that measure the AQI between Spokane, the Valley, and Colbert. Should any one of those hit unhealthy, then they report unhealthy city-wide, but obviously that can still vary from one end of town to the other.
The wind direction is the leading factor here. With winds out of the west, that blows the smoke from the Williams Flats Fire directly into spots like Deer Park and Colbert. But downtown Spokane and the South Hill may still be fairing much better.
Another big factor is the geography of Spokane. The city sits in a valley like a bowl, surrounded by hills on all sides and that can trap smoke and haze when the winds are locally calm and the air is stable. That stagnate air would keep the air quality low in places like north Spokane and downtown (about 1,900') as opposed to the South Hill (about 2,300') which sits 400 feet higher.