(CNN) — Smoke from over 1,000 wildfires that burn in canada It has spread across the northern United States, bringing with it poor air quality and health-hazardous pollution to northern cities in the United States such as Chicago, Illinois and Minneapolis, Minnesota.

Chicago, Minneapolis and Detroit (Michigan) are now among the top three US cities ranked among the 20 most polluted in the world, according to IQAir.

The smoke has spread to the Great Lakes region, in particular, as some 1,090 active fires have burned across Canada, of which more than 670 are considered “out of control”, according to the Canadian Interagency Forest Fire Center. This figure is higher than more than 880 fires of last week.

Most of the country’s wildfires are burning in British Columbia, where more than 460 fires are ongoing, the agency reports.

In the United States, the National Weather Service (NWS) has issued air quality watches for millions of people in Michigan and parts of Minnesota, Wisconsin, Illinois and Indiana .

The hazy sky cover follows a smoke belt from the Canadian wildfires that spread across the United States last weektriggering air quality alerts for more than a dozen states from Montana to Vermont, with smoke reaching as far south as Alabama.

The smoke is expected to drift east across the Great Lakes region through Tuesday and disperse Wednesday, just as the upper Midwest is expected to see some of the highest temperatures so far this year. Minneapolis could reach 38 degrees Celsius and Chicago above 32.

The Illinois Environmental Protection Agency has declared a ‘Day of Action on Air Pollution’ through Tuesday due to ‘lingering’ smoke from wildfires generating heavy pollution air in the region. Similar advisories have been declared in Michigan and Wisconsin.

The city recommends that people with chronic respiratory problems limit their outdoor activities and advises against strenuous activities for children, adolescents, the elderly, people with heart or lung conditions and pregnant women.

“All Chicago residents can also consider wearing masks, limiting outdoor exposure, moving activities indoors, using air purifiers and closing windows,” the agency said. city ​​in a statement Monday.

Wildfire smoke is full of small contaminating particles that can enter the lungs and bloodstream if inhaled. According to the US Centers for Disease Control and Prevention (CDC), the particles can cause shortness of breath and eye and throat irritation, but they have also been linked to more serious long-term health problems, such as lung cancer.

Canada suffers worst fire season on record

The United States will likely suffer the effects of prolonged wildfires in Canada, which continues to record the worst fire season in its history.

According to Canada’s National Fire Center, nearly 29 million acres of Canadian land (about 12 million hectares) have burned so far this year. Smoke from this summer’s fires has so far affected the southern United States and crossed the Atlantic to Europe.

The crisis has sparked an outpouring of international support, with firefighters and emergency responders from countries including the United States, Australia and Brazil deploying to Canada. At least two Canadian firefighters died fighting the flames.

Hard-hit British Columbia will receive federal aid from the Canadian Armed Forces, says advertisement, last week, Public Safety Canada.

According to the British Columbia Forest Fire Service, hundreds of fires in the province have been caused by lightning from thunderstorms. Some of those storms were “dry,” meaning there hasn’t been enough rain to help put out the fires, a dangerous prospect in a province suffering from a severe drought.

As the man-made climate crisis intensifies, scientists predict that wildfire seasons will intensify, especially as droughts and heat become more frequent and severe around the world.

Caitlin Kaiser and Monica Garrett of CNN contributed to this article.