I avoid ice skating at all costs, because I value my tailbone. And now I have all the more reason to stay home, as a CBC News investigation finds that ice-resurfacing machines in hockey and skating arenas can spew particulate matter to a health-endangering extent. At 14 percent of arenas studied across Canada, skaters were breathing in pollution just as dirty as the air next to Canada’s busiest highway. Says researcher Kenneth Rundell:

We found the ice-rink athletes, all the skating athletes, the figure skaters, the short-track speed skaters, and the hockey players had a higher prevalence of exercise-induced asthma … and their lung function was chronically low.

Beware the Zamboni!