Ontario bowed to pressure Tuesday and agreed to strengthen the province''s pollution regulations and push forward their deadline by five years.
The decision was announced as provincial and federal environment ministers wrapped up a two-day meeting in Quebec City.
One of the main items on the agenda was the creation of a smog-reduction strategy.
Norm Sterling, the Ontario Government House Leader, also agreed to curb the acceptable level of ground-level ozone by 20 percent.
The regulations will apply as of 2010 instead of 2015 as Ontario originally planned.
All the provinces, except Quebec, decided to ratify the standards governing ozone, particulates, mercury and benzene in the 1998 Canada-Wide Accord on Environmental Harmonization.
Quebec Environment Minister Paul Begin said although the province did not sign the accord, it will act in a manner consistent with the standards.
The provinces were unable to agree on a strategy to reduce greenhouse gas. But federal Environment Minister David Anderson said he was pleased with the progress made at the meeting.
He said air pollution causes 5,000 deaths in Canada each year and is partly responsible for the high number of respiratory illnesses such as asthma.
by Virginia Sutcliffe