The agency's monitor in Chehalis showed "unhealthy" levels of fine particle pollution, a 167 value on its Washington Air Quality Advisory Tool.
Over the course of the next couple of days, air quality from the Crowsnest Pass, east to the Taber area, south to the US border and north to the Calgary area, is expected to drastically deteriorate.
The low air quality is most likely to have adverse health effects on the elderly, the young and those with chronic heart and lung conditions.
Close windows in your home, if possible, and keep the indoor air clean.
A value of 50 or below represents good air quality with little potential to affect even those with respiratory conditions, while a value over 300 represents hazardous air quality and is likely to affect even healthy individuals.
When air quality reaches unhealthy levels you might think just because you are inside you will not be affected by the smoke, but there are steps you can take to make sure you are not affected.More news: Why Prince Harry and Meghan Markle may 'delay' having a royal baby
N95 or N100 rated masks can help protect some people from air pollution.
The health risks associated with the smoke are accompanied by the melancholy views caused by hazy conditions. Fires burning north and east of Vancouver are adding to the haze, officials said. Meanwhile, lightning strikes over the weekend sparked dozens more fires throughout the state.
And it's unclear when the smoke might leave the region.
Wildfire season can be a disappointment to those who love being outside. If you've got plans to run a marathon today, keep your eye on any updates to the air quality index.
"The last couple years have been a lot worse than previous years", he said. Just do not forget to use your best judgment, monitor air quality, and talk with your doctor.