When Sean Gallagher first visited Beijing in 2005, they simply called it "fog."

The British photographer, who has lived in Asia for the past decade, noticed that very few people in Beijing truly considered the city's notorious air pollution much of an issue.

That attitude shifted in 2006, when Beijing hosted the summer Olympics and the city's choking pollution became a issue in Chinese press.

"It entered people’s consciousness, but wasn’t something people took action to protect themselves against," Gallagher said.



Nine years later, they wear the mask.