Chinese authorities have expanded the number of cities covered by the highest alert for pollution, warning people to stay indoors, urging schools to close, and restricting vehicle traffic.
"The way we capture the air now is a bit of a trade secret," says a co-found of Vitality Air, who goes down to Banff and Lake Louise in Alberta to fill giant cans with air through clean compression.
Dangerous levels of air pollution prompted the city's government to halt outdoor construction and urge schools to close. Authorities told people to stay indoors and implemented traffic restrictions to reduce the number of cars on the road.
We used "science" to see if listening to Oi! would help a runner, a CrossFitter, and a Pilates instructor perform better.