The province has already spent $274 million fighting the fires which so far number 565 and have blanketed the city of Vancouver and other areas with thick smoke.
That unhealthy designation means everyone, especially sensitive groups, should avoid going outside.
At times Wednesday night, Bellingham's air worsened to the "hazardous" range, the worst category, and visibility was less than 2 miles.
Portland, Vancouver B.C. and Seattle were all ranked in the Top 10 for worst air quality, with Portland ranking as high as second on Tuesday morning.
"We have serious challenges for public health and we need to adapt our policy making, working with all levels of government to make sure that as we go forward we're better prepared", said Horgan, flanked by federal Defence Minister Harjit Sajjan, Mayor Lyn Hall and Grand Chief Ed John of the First Nations Summit.
Officials have said roughly 3,000 B.C. residents are under evacuation orders and thousands more are on alert as hundreds of blazes char timber and bush in all areas of the province.
Small particles breathed in from the fires are interpreted as foreign invaders by the body, the same as a bacterium or a virus, Henderson said, adding it mounts an attack, or an immunological response, which leads to inflammation.
The good news is the return to clean air that Western Washington is known for most likely will happen on Friday, according to the National Weather Service in Seattle.
The Shovel Lake fire is considered to be the highest-priority of the more than 560 wildfires burning in B.C.as of Tuesday morning.
After a slight reprieve, smoke-filled skies are back over Calgary.