Conditions are a little better in some parts of the county east of Bellingham, but all areas still have unhealthy air quality.
"Basically went from a more favorable flow where we weren't getting the smoke to westerly flow, which brought all that smoke in from OR", said Bill Wojcik, a meteorologist from the National Weather Service in Boise.
Air quality and smokey skies are expected to gradually improve for most regions throughout the evening and overnight as smoke moves southward.
For people in Vancouver in need of a reprieve from compromised air quality, the City of Vancouver and Vancouver Park Board are providing "cleaner air spaces".
Hazardous smoky air from wildfires could hang around through at least Thursday, the Northwest Weather Service predicted in an update Monday afternoon.
Exposure to particulate air matter - a result of wafting wildfire smoke - is particularly a concern for people with underlying conditions, respiratory infections like COVID-19, pregnant women, infants, children, and older adults.
"The forecast indicates slight improvement in air quality today but ground-level smoke will remain, and possibly until later this week", the notice read. Much of northern Idaho is in the very unhealthy - even hazardous in some areas.