Canadian wildfire smoke causes air quality alerts in Chicago and other US cities

Visibility cut to less than half a kilometre in south-east Michigan

Smoke from Canadian wildfires continued to reduce air quality in US cities as the Great Lakes and other regions awoke to hazy conditions on Wednesday morning.

A tracker from the Environmental Protection Agency's AirNow website showed that swathes of the Great Lakes region were experiencing air quality ranging from “unhealthy” to “very unhealthy”. Parts of central and eastern US were also dealing with poor conditions.

Chicago, which recorded the world's worst air quality on Tuesday, continued to suffer from smoke from the Canadian wildfires as people with health issues were urged to spend less time outdoors. The city's air quality had a reading of 122 – deemed “unhealthy” – on Wednesday morning.

Minneapolis in Minnesota, was issued its 23rd air quality alert as the city's skyline was obscured by a smoky haze. The alert was in place until Wednesday night.

Smoke pouring in from the Canadian wildfires reduced visibility to less than half a kilometre in south-east Michigan, the National Weather Service said. The NWS expected visibility restrictions to continue until 10am local time.

Detroit, Michigan's largest city by population, posted an “unhealthy” air quality reading of 170 on Wednesday morning.

Images captured by Nasa had also shown that the smoke has reached as far south-western Europe, although it will not cause the same hazy conditions or poor air quality because it is higher up in the atmosphere.

The Canadian Interagency Forest Fire Centre reported on Wednesday that 7.8 million hectares have been scorched since the beginning of the year. There are currently 487 active fires in the country, with 253 considered out of control.

Officials said on Tuesday that recent rainfall will give firefighters a better opportunity to control raging wildfires in Quebec, although it will not be enough to extinguish the flames.

AP contributed to this report