Hazy, smoggy conditions have settled down over southern Ontario and southern Quebec today, caused by forest fires burning in northern Quebec.

A smog warning is in effect for most of southwestern Quebec — from Gatineau to Montreal to Drummondville — and a smog advisory was has already been effect for eastern Ontario, and the advisory was expanded to include all the way through Toronto and the GTA, and Hamilton, later today.

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Typically, smog warnings and advisories are caused by stagnant weather conditions causing industrial and car pollution to build up and 'cook' in the sunlight into ozone, fine particulate matter and a mix of other pollutants. However, according to CBC News, this is mostly due to smoke is blowing into the warnings areas from an extensive forest fire near James Bay, that has so far consumed around 250,000 hectares of land.

As of 8 p.m., regions from eastern Ontario to southwestern Ontario were showing Moderate air quality on the Air Quality Ontario website, with Poor air quality in Brampton, Oshawa and Hamilton. Regions around Metro Montreal are reading as Moderate or Poor air quality as well, with the City of Montreal reporting Poor air quality.

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These weather conditions are expected to stick around for another day, so the smog warnings and advisories will be on through tonight and the day tomorrow, but the smoke should clear out on Wednesday night, making it much easier to breathe.

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