Large swathes of the US remained under air pollution alerts on Sunday as bushfires continued to tear through much of North America.
Smoke from the fires blanketed large portions of the western, southwestern and northern states, leading to air quality alerts.
More than 80 fires burnt throughout the country last week amid severe drought and temperatures exceeding 30ºC in places.
The state of California is preparing for potential power cuts as a result of the blazes.
Fires have destroyed more than 1.7 million acres, with the largest single fire covering 413,000 acres in Oregon. Local officials do not expect that firefighters will be able to fully contain the Oregon fire until October at the earliest.
Smoke from fires in Canada has drifted into the northern US, leading to pollution alerts in Wisconsin, Minnesota and Iowa.
The pollution is a particular danger to young children, the elderly and those with heart or lung issues.
Vulnerable residents in Minnesota have been advised to limit their time outside and avoid strenuous physical activity.
President Joe Biden convened a virtual meeting on Friday with governors from the affected states to discuss the fires. Canadian Prime Minister Justin Trudeau contacted Minnesota Governor Tim Walz about the issue.
Bushfires have become more frequent, longer and deadlier in recent years as a result of increasing temperatures owing to global climate change.
The fires last year burnt 4.2 million acres, making 2020 the most devastating season on record.
Fires continue to rage throughout Turkey, Greece and Italy. They have forced thousands to evacuate coastal tourist resort towns in western Turkey.