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Hitting the ice: Air quality in arenas

For many Canadians, trips to the local rink are part their weekly routine. In Canada, more than 2,000 indoor ice arenas are used regularly by hundreds of thousands of people for activities such as hockey, figure skating, ringette and public skating.

While cheering on our favourite athlete or participating in our favourite pastime, it’s important to trust that the air we are breathing is safe. Resurfacers and edgers (commonly called by the brand name Zamboni), used to keep the ice nice and fresh, are typically propelled by propane or natural gas engines. These emit air pollutants such as carbon monoxide (CO) and nitrogen dioxide (NO2), both of which can be bad for our health.

Exposure to these pollutants can cause difficulty breathing, eye and respiratory irritation and flu-like symptoms. They can also worsen asthma symptoms. Children, the elderly and those with pre-existing medical conditions are more likely to experience these effects on their health.

From 2017 to 2020, a team of Health Canada scientists set out to provide recommendations on monitoring and improving air quality in arenas.

“There was limited understanding of the air quality in arenas,” explains scientist Aaron Wilson. “More research was coming out, demonstrating that these pollutants could have adverse effects at much lower levels than we had previously thought. We wanted solid evidence to make appropriate recommendations to managers of ice arenas.”

“Arenas are unique environments, in that people are exercising. When you exercise, you breathe in more often and deeper, and that means you take in more of the indoor air pollutants,” says scientist Christie Cole. “It’s a higher intensity situation...where the competitiveness of something like a hockey or ringette game can fuel people to push themselves.”

The team of scientists monitored the air quality for seven consecutive days in eight arenas in Saskatchewan and Ottawa, Ontario. At the same time, they monitored the air quality outside the arenas so they could compare the air quality between the two environments. To properly set up the monitoring stations, scientists assembled sensitive equipment in special boxes that could be placed in the arena or outside.

The air monitors take in the surrounding air and sensors continuously measure the concentrations of pollutants like CO and NO2, with the help of integrated ultraviolet lights. These were turned on 24 hours a day, and provided data to help researchers evaluate air quality at different times throughout the sampling period.

Ideally, all arenas would be air-quality monitored continuously so issues could be identified and corrected immediately, but because of the high cost that is not an option for many arenas.

The information the researchers obtained allowed them to provide better guidance on when and where to monitor the air quality in arenas to get the best results. The scientists recommend sampling when the ice is frequently resurfaced, and placing samplers in the timekeepers’ box, where levels of pollutants were similar to those near the ice surface, and where monitoring equipment was accessible yet protected.

“We also didn’t know how the levels changed during the day,” says Wilson. “Do they only peak when the ice is being resurfaced, or do the air pollutants accumulate throughout the day?”

Over the course of their research, the scientists noticed that NO2 levels would increase over the course of the day and be highest at the end of the day. They also observed that even in the morning, levels were higher than those found outside. This led them to recommend actions that ice arena managers could take to improve air quality in their facility.

For example, arenas that have difficulty reducing pollutant levels with their current ventilation practices are encouraged to consider running continuous ventilation for a few hours overnight in addition to regular ventilation, to clear out the accumulated pollutants from the previous day.

The team also looked at the different fuel types that were used by ice edgers and resurfacers. They found that propane and natural gas systems emitted similar levels of NO2, but less than older, less efficient gasoline models. “Ultimately, switching to electric resurfacers is the best way to eliminate indoor air pollutants, but it is a bit costly up-front and it will take time for all arenas to be able to do that,” says Wilson.

Thanks to the hard work and dedication of the research team, Health Canada can now share best practices for improving air quality in ice arenas. These include general practices that can be put in place in different arenas, based on their specific needs. “Buildings aren’t all the same. The advice includes different strategies with varying levels of complexity and different costs so that arena managers can try to improve their indoor air quality based on their own situation,” says Patrick Goegan.

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