Wildfires have led Environment Canada to issue air quality advisories for parts of British Columbia, Alberta, Manitoba, Saskatchewan and the Northwest Territories, as forecasters warn the smoke could drift farther east.

"Wildfire smoke is causing very poor air quality and reduced visibility," Environment Canada said in a special air quality statement. "Wildfire smoke can be harmful to everyone's health even at low concentrations."

The air quality advisories currently cover northeastern B.C. around the town of Fort Nelson. In Alberta, the northern half of the province is under smoke-related advisories, including communities like Fort McMurray, High Prairie, High Level, Grande Prairie and Fort Chipewyan. Of the 86 air quality alerts in effect across Canada Tuesday afternoon, 65 are for Alberta, which is also covered by the most severe alerts currently in place.

Fort Vermilion, Alta., had the worst air quality in Canada Tuesday afternoon, Swiss air quality monitoring website IQAir reported, with an air quality index of 238 as of 4 p.m. MST.

Air index quality scores between 201 and 300 signal that the air has become "very unhealthy" to breathe, and everyone exposed to it risks experiencing health issues, according to IQAir.

The Alberta communities of Fort Smith and Manning weren't far behind, with air quality indexes of 199 and 175 respectively. Air with scores ranging from 151 to 200 is considered unhealthy for everyone, though sensitive groups including children, seniors, pregnant people, and those with cardiac and pulmonary diseases are susceptible to more severe health impacts.

The advisories also cover central Saskatchewan, including communities like La Ronge and Cumberland House, and neighbouring Manitoba towns like Flin Flon and The Pas. In the Northwest Territories, areas south of Yellowknife are currently impacted, including the Hay River and Fort Providence regions.

Wildfire smoke moving across Canada

"Take a break from the smoke at a location in your community where you can find clean, cool air," Environment Canada advised. "It is important to listen to your body and reduce or stop activities if you are experiencing symptoms."

According to CTV Your Morning's meteorologist Kelsey McEwen, smoky conditions will continue into Wednesday as wind gusts increase to between 50 and 60 km/h in northeastern B.C. and northwestern Alberta, sending smoke eastward.

Wildfire smoke is expected to continue spreading south in Manitoba and Saskatchewan to cities like Winnipeg and Saskatoon. Wildfire-related haze could also move east into Ontario and Quebec, affecting areas from Georgian Bay to Quebec City. Northern Manitoba and southern parts of Nunavut could also be smoky by Wednesday morning.

According to data published by the Canadian Interagency Forest Fire Centre (CIFFC) as of 7:12 p.m. ET, there are 133 active wildfires burning across the country, down from 138 reported earlier Tuesday. The CIFFC reports 41 are currently considered "out of control." Alberta has the most active fires, at 45, followed closely by B.C., at 44. Fires are also present in Northwest Territories, Saskatchewan, Manitoba, Ontario, Quebec and New Brunswick.

South of the border, smoke from fires burning in Canada was visible as far as South Dakota on Tuesday, and weather officials there have issued warnings for reduced air quality in several counties.

Meanwhile, satellite imagery posted to X by the Cooperative Institute for Research in the Atmosphere showed smoky conditions in parts of the northern United States on Monday and Tuesday.

Several states, including California, Oregon, Washington, Idaho, Montana, Wisconsin, Michigan, Illinois, Indiana, Ohio, Pennsylvania and New York, were reporting a moderate air quality index on Tuesday. 

The Oregon towns of Three Rivers and Sunriver reported the worst air quality in the United States on Tuesday afternoon, according to IQAir with air quality indexes of 178 and 165 respectively, as of about 3 p.m. PST.