Air quality statements have been issued for Alberta, Saskatchewan and Manitoba, as well as northwestern Ontario. By Wednesday, Edmonton was expected to see a similar major reduction in air quality.
All athletic practices for Tacoma Public Schools have been moved indoors, a district spokesman said.
An Air Quality Alert is in effect for Western Washington until 5 p.m. on Wednesday.
As winds shift and pick up, thick smoke from hundreds of wildfires burning in British Columbia is being pushed into the South Sound. Smoke could worsen into unhealthy levels by Monday, the agency said.
For now, Missoula could really use some upper level winds coming from the cleaner air of the east.That should drive out some of the smoke and bring Missoula County back to a healthy level.
Those who typically walk or jog to work are advised to consider taking a bus or Skytrain instead until the air quality improves.
Weather warning issued ahead Storm Ernesto's arrival this weekend and ugh
The remnants of the storm will hit Connacht around 6pm on Saturday night and will reach the east coast by around midnight. Yorkshire is set to be hit by long periods of heavy rain over the weekend as Storm Ernesto looks set to batter the UK.
The Federal Aviation Administration said airplanes bound for the Sea-Tac International Airport, Seattle's main airport, may be delayed because of low visibility.
"Definitely, it's a concern for people, especially those with asthma and other pre-existing conditions where this real poor air quality can definitely cause them to experience symptoms", said Jim Kelly, with the state's health department. All aquatic centers are closed Sunday, and Spokane Recreational League events are cancelled.
MPCA says the smoke is expected to completely exit the state by 9 a.m. on Tuesday.
In Portland, six tourists from Lincoln, Nebraska, posed for a photo in front of the Willamette River with the usual Mount Hood backdrop shrouded in haze.
"We are disappointed that we can't see the mountains and the whole city, because our relatives live here and tell us how pretty it is, and we're missing it", Bev Harris said.