![China riot police seal off city centre after smog protesters put masks on statues | China | The Guardian China riot police seal off city centre after smog protesters put masks on statues | China | The Guardian](https://i.guim.co.uk/img/media/6ebb78cd9b54bd476972167d3674a7f9998235b7/445_339_7767_4661/master/7767.jpg?width=465&quality=85&dpr=1&s=none)
China riot police seal off city centre after smog protesters put masks on statues | China | The Guardian
![A Chinese man wears a face mask while walking on a sidewalk in heavy pollution in Beijing on January 9, 2018. China's air pollution is causing its residents to die three years A Chinese man wears a face mask while walking on a sidewalk in heavy pollution in Beijing on January 9, 2018. China's air pollution is causing its residents to die three years](https://c8.alamy.com/comp/W01DWY/a-chinese-man-wears-a-face-mask-while-walking-on-a-sidewalk-in-heavy-pollution-in-beijing-on-january-9-2018-chinas-air-pollution-is-causing-its-residents-to-die-three-years-early-according-to-a-new-study-by-the-academy-of-sciences-photo-by-stephen-shaverupi-W01DWY.jpg)
A Chinese man wears a face mask while walking on a sidewalk in heavy pollution in Beijing on January 9, 2018. China's air pollution is causing its residents to die three years
![Pollutionwatch: do face masks really prevent the ill effects of pollution? | Air pollution | The Guardian Pollutionwatch: do face masks really prevent the ill effects of pollution? | Air pollution | The Guardian](https://i.guim.co.uk/img/media/23ebff09269888bec1e21dd2d1fd67a159bbe4ad/0_267_5229_3137/master/5229.jpg?width=1200&height=1200&quality=85&auto=format&fit=crop&s=7d07eb44ee14a650e03ca692d30c9001)
Pollutionwatch: do face masks really prevent the ill effects of pollution? | Air pollution | The Guardian
![People and commuters wear face masks on their way to work, braving heavy air pollution in the Chinese capital city as levels soared to more than 20 times the safety levels resulting People and commuters wear face masks on their way to work, braving heavy air pollution in the Chinese capital city as levels soared to more than 20 times the safety levels resulting](https://c8.alamy.com/comp/F8E6KW/people-and-commuters-wear-face-masks-on-their-way-to-work-braving-F8E6KW.jpg)