There is a Smog Advisory for today, Thursday June 20th. The definition of a Smog Advisory is quoted below.

A Smog Advisory means that there is a strong likelihood that there may be poor air quality within the next 24 hours due to ground-level ozone and particulate matter.
Taken from the www.airqualityontario.com web site.

You can check the current conditions at this Ontario Ministry of the Environment web site. The readings were good this morning but that will change as the temperature increases.

There are spare the air actions that you can take. They are listed here. There are also actions that the three levels of government can take. What they actually plan to do will be outlined tomorrow at the Smog Summit Political forum