OTTAWA - The federal government's new clean air plan will exempt Alberta's oil sands -- alone among all sectors of heavy industry in Canada -- from a requirement to cut two smog-causing chemicals.

And that has environmentalists issuing a pollution warning.

An Environment Canada document provided to non-government groups last week projects a 60 per cent rise in emissions of volatile organic compounds from the oil sands by 2015, and a five per cent increase in nitrous oxides emissions over the same period.

Volatile organics and nitrous oxides cause smog when mixed in sunlight.

"Every other sector has reductions,'' said Emilie Moorhouse, executive director of the Sierra Club. "Albertans' air quality is going to suffer because of this.''

The federal plan also allows new oil sands projects an exemption from greenhouse emissions-cutting targets for the next three years, which will allow for rapid expansion of the industry.

Nashina Shariff, associate director of Alberta-based ToxicsWatch, predicted Fort McMurray's smog will exceed Canadian health standards within five years.

Nationwide, the Conservative plan calls for a 45 per cent cut in emissions of volatile organics and a 40 per cent cut in emissions of nitrous oxides from 2006 levels by 2015.

The government says its plan provides nationally consistent regulations and a level playing field across Canada.

Ottawa intends to hold public consultations on the air pollutant targets in the coming months, and finalize regulations by 2010.

Sector-specific targets for cutting greenhouse emissions, as distinct from smog-causing pollutants, have not yet been released.

Eric Richer, a spokesman for Environment Minister John Baird, said the oil sands exemptions were not new because they were posted on the department's web site last week.

He said the Tory plan will cut air pollution in half by 2015.

"In the oil sands, because of our regulations, air pollution is being controlled unlike ever before,'' said Richer.

"The key air pollutants will be below ... where they would have been in 2015 without our plan.''

Liberal environment critic David McGuinty said he has been trying to determine whether the government has conducted socio-economic analysis of the impact of new clean air regulations, as he said should have been done.

Repeated questions in the Commons have failed to produce answers, he said.

The oil sands are the fastest-rising source of greenhouse emissions in Canada, and there are growing concerns about their environmental impact. Former Alberta Premier Peter Lougheed has said the current rate of development should be slowed.