Ground level ozone: history

Ground-level ozone has long been recognized as a pollutant of concern. National Ambient Air Quality Objectives (NAAQOs) for ozone were established under the Clean Air Act (now subsumed into the Canadian Environmental Protection Act (CEPA)) in the 1970's. However, Canada only began giving serious consideration to the need to manage ground-level ozone in the mid-1980's after some success had been achieved in addressing the number one air issue of the day - acid rain. Canada's commitments in the 1988 NO_x Protocol under the United Nations Economic Commission for Europe (UNECE) Convention on Long-Range Transboundary Air Pollution (LRTAP) were based primarily on the contribution of Nitrogen Oxides (NO_x) to ground-level ozone. The first major national effort to address ground-level ozone came with the endorsement of Phase I NO_x/VOC Management Plan by the Canadian Council of Ministers of the Environment (CCME) in 1990. Additional ozone management agreements and programs continued to be established over the period from 1990 to date. The most recent major agreements addressing ground-level ozone are the Canada-wide Standards for PM and Ozone endorsed by CCME in 2000, and the Ozone Annex to the Canada-U.S. Air Quality Agreement signed by Canada in 2000.