They are one of the first lines of defense against the choking smog that regularly blankets major cities and are seen as a necessity by millions of city-dwellers.
As acceptance grows, masks are moving from function to high-fashion. Style-savvy types match it with their outfits and Chinese designers from Paris to Shanghai have incorporated Swarovski-studded pieces or post-apocalyptic looks into their runway shows.
Perhaps the most outlandish vision belongs to Beijing designer Wang Zhijun, who has turned the surgical-style masks into an art project to raise awareness about China's pollution problems.
By repurposing high-end sneakers -- the kind that have sneakerheads foaming at their mouths -- into designer face masks, he's hoping to make a personal statement about the impact of pollution, as well as start a conversation among his peers.
"The masks make an impression, but they also show that you can use basic, everyday stuff to bring change into your life," he says.
"If that helps to raise environmental consciousness, then I can consider myself fairly satisfied. Though there's much more to be done."
Wang first started using designer sneakers to make face masks in 2014 and has since produced around 20 different pieces. Although initially running under the radar, one of his most recent works left many shoe hoarders cringing in disbelief.
He created what was possibly one of the most sought-after pollution masks ever made, using a pair of Kanye West-designed, limited edition Adidas Yeezy Boost 350 V2s. A pair of the coveted sneakers reportedly once resold on eBay for $10,000
"I didn't even wear them. I took them out of the box and just cut them up to sew the mask," Wang recalls.
After Wang put the mask up for sale on eBay China in October, it drew a bid of more than $5,000. Far more than the $700 he had paid for the shoes, eBay ultimately blocked the transaction due to its price limits on first-time sellers.
But sale or not, Wang's work gave him exactly what he'd hoped for.
"Many western websites dedicated to fashion and footwear reported on the Yeezy mask. My other masks got a lot of attention, too. People started emailing me to ask where they could buy them," Wang says.
"But I'm not making them for a profit. Their purpose is to raise awareness about pollution in China. They are a creative project -- my own campaign to tackle the issue."
Wang, who is a runner and avid sneaker collector, developed the idea after one of the regular blankets of smog that so often shrouds Beijing made it difficult for him to exercise outdoors.
"I used to run around my neighborhood in central Beijing, until I couldn't anymore. It would hurt my lungs, making it difficult to breathe," he says.
"I started reading up about pollution around then -- on English-language outlets, our country doesn't really say much about it. That's when I decided to act, starting from what I know best, and what's around me."
The 34-year-old had previously worked as a graphic designer at Puma and Saatchi&Saatchi and having created his own custom-made pair of Nikes inspired by the Chinese New Year horoscope
, he decided to turn his passion for tinkering with sneakers into something more practical.
He carefully drafted the idea for his first designer sneaker face mask, and used an all-black cover made of a panel from a Nike jacket and a Nike Flyknit racer silo shoe.
On his second attempt he moved exclusively to using sneakers and now incorporates most parts of the shoe -- from laces and insoles to side panels and tongues -- into his masks, without even sketching out his designs.
"I just picture the mask, and start dissecting the shoes. It comes naturally," Wang says.
Each mask is unique, and takes him around five days to craft. Although Wang used 3M filters from the local convenience store for his early models, his newest ones are fitted with Respro filter valves imported from the UK.
Health professionals haven't tested them, but the designer believes they are fully functional.
"I ran a half marathon in one of them, and noticed discoloration afterwards. They work," he says.
You won't find him sporting his own masks these days -- since catching global attention, the designer mostly uses them for promotional photoshoots.
And while at first he had to dig into his own sneaker collection or those of his friends, big brands have started sending him their latest models to be dissected.
"They all thought I was crazy initially, but then they got on board with the project and started offering up their sneakers," he says.
Puma has now featured his work in one of its global campaigns
and watch company Swatch recently asked him to create a bespoke mask
for one of its ads.
Regardless of the commercial attention, Wang seems determined to keep the masks a passion project.
"I am happy to collaborate with labels, but I am really not interested in turning this into a mass-scale venture. Nor do I care to attract the fashion crowd simply because my work 'looks cool,'" he says.
"It's about keeping the focus on the pollution problem, not about running a business or looking trendy."