Ontario is committed to protecting our air, ensuring we have strong environmental standards that are protective of human health and the environment, and taking action to enforce local air quality standards.

Ontario’s emissions trading regulations on sulphur dioxide and nitrogen oxides (O. Reg. 397/01 and O. Reg. 194/05) introduced in the early 2000s have contributed to the reduction in nitrogen oxides emissions, particularly in the early years of the program.

Nitrogen oxides emissions from on-road vehicles have also decreased due to the phase-in of new vehicles having more stringent emission standards.

Emissions from heavy-duty vehicles however have not decreased as rapidly. Heavy-duty vehicles remain a significant source of nitrogen oxides, a pollutant that contributes to smog formation, and fine particulate matter.

Since 2018, some of our progress has included:

  • Implemented an enhanced emissions testing program for commercial trucks and buses to further reduce pollutants in our air.
  • Secured the services of consultants for the Sarnia Area Environment Health Project to assess the risk of air pollution in the Sarnia area.
  • Enhanced our Air Quality Health Index (AQHI) and roadside monitoring networks with:
    • a new Milton AQHI air monitoring station to address the needs of Halton-Peel and better understand the unique airshed in southern Ontario
    • new technology in Hamilton to collect data to help interpret traffic-related pollutant measurements.
  • Assessed the impacts of the COVID-19 pandemic on air quality in Ontario by using data collected at our network of roadside air monitoring stations that show that concentrations of several common air pollutants associated with transportation and other major emissions sources generally decreased during the initial stages of the provincial declaration of an emergency.
  • Continued our air quality reporting that confirms Ontario’s actions to reduce airborne pollutants are working and that regional air quality has been steadily improving in Ontario for many common air pollutants over the past 10 years.