Hazy day in Beijing

Commuters wear masks to protect themselves from breathing in pollution on a smoggy day in Beijing in 2016, although regular surgical masks don’t protect against PM2.5 particles, which pose health risks. This year, however, many residents of Beijing noticed an improvement in air quality, almost certainly the result of government measures to crack down on sources of pollution — see, for example, this January 11 story in the New York Times, “Pollution appears to ease in Beijing amid China’s drive to clear the air” (paywall), or this Bloomberg story on the same theme.