The new agreement updates air quality standards for the first time in 20 years, starting with sulphur dioxide, nitrogen dioxide and volatile organic compounds, two of the main contributors to smog.
But agreements with some industrial sectors to set limits on their emissions are still ongoing.
"We're really still in the early stages," said federal Environment Minister Peter Kent. "There's still negotiation to be done in terms of industrial emissions standards."
Kent couldn't say how much air quality in Canada would improve under the new, non-enforceable, guidelines.
"The obvious outcome is to find performance standards which enable us to achieve reductions, to having cleaner, safer, less toxic air," he said. "This is still a work in progress."
The agreement contains two parts: guidelines that set limits on the presence of certain air contaminants in the atmosphere, and industrial requirements that govern emissions from different sectors.
Industries such as forestry and mining have already agreed on their levels. The energy industry, including the oilsands, is among the sectors still under negotiation.
Alberta Environment Minister Diana McQueen said there's no timeline to complete those talks, but that they are proceeding in a "timely" fashion.
"There's more work we need to do with certain sectors," she said.
While the agreement is national in scope, it will be implemented by the provinces, who will be able to interpret it differently to suit their circumstances.
"The touchstone word in the agreement that we've achieved here this week is flexibility, in recognizing the balance between environmental remediation and correction as well as making sure that we keep an eye on not discouraging investment," Kent said.
Quebec has not signed the agreement, but has promised to work with other provinces and supports the general goals of the standards.
McQueen said the agreement allows provinces to decide for themselves what they will do, as long as the air quality standards are met.
She said it's not necessary to enshrine the standards in regulations, since industry is agreeing to them.
"We already have buy-in from stakeholders," she said. "I don't see a need for regulations."
But John Bennett of the Sierra Club says that means when companies exceed their emissions limits, they won't face consequences.
"Each exceedance is subject to further negotiation," he said.
He added that the agreement is likely to lead to a patchwork of different environmental standards across the country, which could even affect where industries decide to locate.
The announcement comes after a two-day meeting of ministers in Lake Louise, Alta. Negotiators have been working for five years on the smog deal, in conjunction with industry and non-governmental groups.
Prime Minister Stephen Harper promised in 2007 that smog would be cut in half by 2015.
Kent couldn't say if Thursday's agreement would achieve that goal. Environmental groups have said the deal doesn't go that far, but will eventually result in real improvement.
The Canadian Medical Association found in 2008 that 21,000 Canadians die prematurely every year because of air pollution. Most of those deaths are from accumulated exposure over years, but 3,000 are the result of short-term acute exposure, the study said.
The CMA said that in 2008, air pollution was the cause of 9,000 hospital visits, 30,0000 emergency department visits and 620,000 doctor's office visits.
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