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Notice of Smog Advisory

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Notice of Smog Advisory

Effective immediately, the Ministry of the Environment is expanding its existing Smog Advisory to include the following additional forecast regions:

  • City of Hamilton
  • Halton-Peel
  • City of Toronto
  • York-Durham

East to northeasterly flow of polluted air from forest fires in Quebec is resulting in high smog levels over eastern and parts of southern Ontario today.

This advisory will remain in effect until further notice.

  • A Smog Advisory is related to the Air Quality Index (AQI), which rates how clean the air is. The AQI scale ranges from 0 to 100+. Higher numbers mean higher health risks.
  • A Smog Advisory is issued in your region when the AQI is expected to reach 50 in the next 24 hours. It can be lifted once the AQI is expected to reach or drops below 50.
  • Smog is made up of a complex mixture of air pollutants that are sometimes visible, such as a brownish-yellow haze over cities; sometimes not. The two main ingredients of smog are ground-level ozone (O3) and fine particulate matter (PM2.5).
  • Smog is harmful to the lungs and heart. Even in healthy people, smog can reduce lung function.

For more information:

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