The polluted air inside some Canadian hockey arenas could be putting children at risk, a CBC News investigation reveals.

The report found the exhaust that routinely streams out of ice resurfacing machines in skating arenas is to blame for high levels of tiny particles, which experts say are having an effect on people who skate in rinks.

"It's quite serious. I think you'll find a large number of arenas have high levels of ultrafine particles," said Kenneth Rundell, who runs the human performance lab at Marywood University in Scranton, Pa.

Pollutant particulates that have a diameter of less than 0.1 microns are defined as "ultrafine particles" — particles so small they can easily deposit deeply into the lungs, agitating asthma and some cardiovascular illnesses.  Lung cancer and heart disease are commonly known as diseases related to high exposure of ultrafine particles that can be inhaled.

With Rundell's help, the CBC tested 42 arenas in Halifax, Sudbury, Winnipeg, Edmonton and Vancouver.  Of those rinks, 24 per cent tested higher than 60,000 particles of pollution per cubic centimetre — a level that Rundell said decreases lung capacity.

What's more, 14 per cent also tested higher than 100,000 particles of pollution per cubic centimetre, roughly the equivalent of the air quality that might be experienced standing next to Toronto's Highway 401, the busiest road in the country.

In some of the arenas tested, the CBC found that ice resurfacing machines spewing the microscopic pieces of toxic dust operated once every hour.  An arena in Winnipeg peaked at 250,000 particles of pollution per cubic centimetre.

"When I worked for the Olympic committee, we made this observation that ice rink athletes tended to have a much higher prevalence of asthma," Rundell said.

Curbs for children suggested

He believes it is the pollution in the arenas that is damaging the lungs of hockey players and figure skaters.

Rundell advised limiting the time young people spend in arenas if they're filled with hundreds of millions of ultrafine particles.

Jeff Brook, the senior research scientist with Environment Canada, is among dozens of scientists around the world beginning to study how ultrafine particle pollution is affecting health.

"We really should be trying to make attempts to minimize kids' exposure to ultrafine particles while waiting for more info to come in on their impacts," he said.

Improving ventilation systems in buildings or installing vents nearer to the ice rather than in the roof could help clear the air indoors.  Another, more costly solution is to start using ice resurfacing machines powered by electricity to eliminate the use of fossil fuels.  But those kinds of machines are not likely to become commonplace, as they might run into the six figures.