The Conservatives' proposed Clean Air Act received a rocky reception from opposition MPs and environmentalists, who were quick to dismiss the bill as a "hot air plan."

The minority government released the centrepiece of it "made-in Canada" environmental agenda on Thursday, a Clean Air Act that aims to cut greenhouse gas emissions in half by 2050.

The legislation will give Ottawa "new and stronger powers to do the things we need to do to protect the health of Canadians and our environment," Environment Minister Rona Ambrose told a news conference.

"We will be the first federal government to introduce mandatory regulations on all industry sectors across Canada to reduce air pollution and greenhouse gases,'' Ambrose said.

Federal Health Minister Tony Clement lauded the bill, saying that smog leads to thousands of deaths each year.

"We're the first government to tie our environmental policy to health outcomes," Clement told CTV's Mike Duffy Live.

He dismissed the suggestion that the Clean Air Act was not an immediate response to environmental concerns. Asked when people in Toronto are going to be breathing better air, Clement said: "The short answer is 'even today.'

"Because of the action this government has taken on transit passes making it easier to acquire a transit pass with a tax break, that has meant 56,000 cars a day off the roads -- that helps Toronto," he said.

Regardless of whether the Clear Air Act passes and separate from the consultative process on automobiles, the Conservative government will use current legislation to attack air quality issues, Clement said.

Ambrose told reporters Thursday that the auto sector target, a 5.3 megaton reduction by 2010, "is the equivalent of taking another several hundred thousand cars off the road. These are very immediate reductions."

The government will also introduce regulations over the next year to slash emissions from motorcycles, outboard engines, all-terrain vehicles and off-road diesel engines.

But officials were unable to say what proportion of emissions come from those sources, or by how much they will be reduced.

On Friday, after the plan endured a day of tough criticism, Ambrose defended the legislation saying she had received some encouragement form former prime minister Brian Mulroney -- lauded as the 'greenest' prime minister by environmentalists.

"This is a key turning point," Ambrose told CTV's Canada AM. "I had the privilege of talking to Mr. Mulroney yesterday about this and he gave me a great boost by saying this is how people felt about the acid rain agreement, but it's a key turning point."

Ambrose also pointed out that the Canadian Medical Association commended the government's plan because it recognizes that "environmental outcomes have an impact on health outcomes."

Opposition swift to attack

All three opposition parties in the House of Commons have said they will vote against the bill, meaning it has no chance of passing into law in the current minority Parliament.

In Thursday's session of question period, interim Liberal Leader Bill Graham called the rhetoric on the party's environmental policies "hot air" without substance. 

"Why is the government violating its responsibility to the environment, children, and the future of our planet?" he asked.

Harper's Parliamentary Secretary Jason Kenney responded by questioning the Liberal strategy on the environment.

"Every single Liberal leadership candidate who has proposed targets for greenhouse gas emissions had proposed that those targets will be met by 2050," Kenney said.

"The difference is this ... we are committing today, for the first time ever, to introduce meaningful, tough regulations to reduce greenhouse gas emissions by 65 per cent by 2050. We'll do far more than the Liberals ever did," he said.

Bloc Quebecois Leader Gilles Duceppe waded into the debate to say the Conservatives were soft on the environment.

"Will the prime minister admit that after nine months he gave birth to an empty shell; and in that time, greenhouse gas emissions continue to increase and will continue to increase until 2010?" Duceppe asked in French.

But Kenney stood firm on the party line, telling his parliamentarian peers that the Conservative government was the first to establish air-quality objectives.

"I will admit easily that this is the first government that has taken concrete action to reduce greenhouse gas emissions, to reduce pollutants, to table a bill, to improve the quality of our environment with real and strict regulations," he said.

NDP MP Libby Davies contested those assertions in question period, arguing that the Clean Air Act was nothing but lip service.

"Just like the Liberals, the Conservatives are going to make the air Canadians breathe a whole lot dirtier. Despite what the minister says, there are no caps on greenhouse gases, there are no targets for the industrial sector, and by the government's own admission, pollution will not go down, it will go up," she charged.

"Can the prime minister explain why he just gave his friends in big oil and big industry a 20-year pollution holiday?"

Kenney defended the plan, again asserting that the government, "for the first time" introduced meaningful regulations that give the government the power to restrict greenhouse gas emissions.

Activists voice concern

Environmentalists were quick to voice their opposition to the bill.

"There is really no news here,'' Green party Leader Elizabeth May told the Canadian Press. "Canada stands alone repudiating Kyoto.''

Aaron Freeman of Environmental Defence said the proposed Act was effectively abandoning the Kyoto Protocol and the target it set.

"If you can't meet the target, then you are not meeting the Kyoto (Protocol)," he said.

The Sierra Club blasted the vehicle emissions plan as too little too late.

"The proposed federal regulations presented today by the Harper government line up with the outdated and weak standards of the Bush Administration, not the stringent standards of the state of California,'' the group said in a news release.

Details on the Clean Air Act

The bill seeks to cut emissions from 2003 levels by 45 to 65 per cent by 2050.

In the meantime, the government will set so-called "intensity targets'' which would obligate industry to reduce the amount of energy used per unit of production, without implementing a set restriction on emissions.

Industrial polluters would have until at least 2010 before they would face regulations and the government is giving itself until 2020 to set national emissions-cutting targets for the pollutants that cause smog.

The proposed law makes no reference to the Kyoto Protocol although Canada remains a party to the treaty.

The government is moving forward with a three-phase consultation process on targets for large industrial emitters, which account for about half of Canada's greenhouse pollution.

Furthermore, the Clean Air Act will redefine a number of substances, which were previously labelled as toxic, as "air pollutants."

The government also intends to align Canadian regulations with the rules of the U.S. Environmental Protection Agency, while there will be new rules for the fuel efficiency of cars and trucks by 2010.

The Act is likely to be greeted by intense debate within the Commons environmental committee, which must study the Act before it can be approved.

Other highlights from the proposed Clean Air Act:

• By 2011, produce new regulations for vehicle fuel consumption
• By 2025, set federal targets for smog and ozone levels
• Harmonize vehicle emissions standards with those of the United States over the next 12 months
• Align regulations with those of the U.S. for volatile organic compound emissions
• Work with provinces to create system for mandatory reporting of air emissions and avoid regulatory overlap
• Introduce environmental damages fund that applies non-compliance fines directly to cleanup

With files from The Canadian Press