Canadian wildfires are continuing to send heavy clouds of smoke south, from Northern Ontario and Quebec, through both provinces and into the United States.
Environment Canada has issued special air quality statements for large areas of Ontario and Quebec warning of high levels of air pollution due to the smoke.
The agency says wildfire smoke plumes moved into the impacted areas including the Greater Toronto Area, Hamilton, Windsor, Barrie and London in Ontario and most of northern Quebec.
It says people with lung or heart disease, older adults, children and others are at higher risk of suffering adverse health effects of forest fires smoke.
The agency says wildfire pollution level can fluctuate over time and can vary depending on the location, but air quality is expected to improve for some areas on Thursday night.
Air quality warnings are also in effect in Chicago and Detroit and along with Toronto, they occupy three of the top four spots on Air-I-Q's global ranking for poor air quality.
As of this morning, Dubai in the United Arab Emirates tops the list of major cities with a significant score of 411 -- putting its air quality in the "Hazardous" category. Detroit ranks second, followed by Chicago, and Toronto in fourth, with an "Unhealthy for Sensitive Groups" rating of 159.
Still, some of the smaller communities in Southern Ontario are fairing far worse, with Sarnia scoring 372, as of 3:30 a.m., a score that places the city not far behind Dubai. Air-I-Q updates its numbers hourly.
The Canadian Interagency Forest Fire Centre's website shows there are 487 active fires burning across the country this morning, with 253 of them classified as out of control.
As of Tuesday afternoon, there were 66 active fires in Northern Ontario, and as of this morning, 76 fires were burning across Quebec.
