Blue skies, sunshine, and no breeze -- it's a recipe for smog in Metro Vancouver.

Air pollution can make daily activities difficult for people with breathing problems. But new research suggests it can affect a lot more than that.

"We were actually looking at the relationship between air pollution and birth outcomes," said Dr. Michael Brauer, of the School of Environmental Health at the University of British Columbia

UBC researchers looked at 70,000 births over a four year period.

They compared each baby's home with a high resolution map of air pollution.

The results were a cause for concern.

The study found that people who lived within 50 metres of a major road (including a provincial highway) had about a 20 to 25 per cent increased risk of giving birth to a baby that had low birth weight (defined as weighing less than 2500 grams or 5.5 pounds) .

Babies born underweight, or prematurely, are at risk for long term health effects, including developmental disabilities and chronic lung disease.

Dr. Brauer says the study may make pregnant women think twice about their exposure to air pollution.

"We now have to think about pregnant women being sort of a vulnerable group," he said.

Most of the air pollutants in their study came from vehicle traffic and construction projects .

"We primarily saw carbon monoxide, nitrogen oxides. both of which are really strong indicators of vehicle emissions," said Dr. Brauer.

With certain areas being hot spots for pollution - he says the results could have direct implications for urban planners.

"Are we actually trying to put people in the same places where we're trying to move goods for example, are we trying to put people along our traffic corridors where they're actually exposed to air pollution."

With the increasing variety of health risks associated with air pollution, it's even more important to reduce emissions and adopt a greener lifestyle. The research team has published maps showing annual average air pollution levles, low birth weight rates and neighbourhood income levels in various Metro Vancouver communities. For this inforamtion, see

With a report by CTV British Columbia's Dr. Rhonda Low.