Sales of air purifiers and face masks are booming in China as citizens attempt to protect themselves from the lung-choking smog that plagues many of the country's cities. Total sales of air purifiers hit 3.5bn RMB (£293m) in 2013, according to Daxue Consulting who have carried out market research. "There is 80-100% growth year-on-year compared to 2012," said Matthieu David-Experton, CEO of Daxue Consulting, which has offices in Shanghai and Beijing. More than 40% of these sales in 2013 were recorded in November and December when air pollution levels were particularly high, according to their figures. Sales of face masks have also risen dramatically with many retailers in Beijing reporting that they had sold out stock during the city's most recent bout of smog. One manufacturer, 3M, which sells its products on Tmall, sold out of 26 of its 29 products. Louie Cheng, president of PureLiving China, an indoor environmental consulting company based in Shanghai said his company's sales of face masks and air purifiers surged when air pollution levels reached off index levels in the city last December.

"After that particularly bad week at the beginning of December, over a two day period we probably had 300 clients pass though our office to buy filters and masks," Cheng said. "We were sold out of things. There was a clearing of the shelves sort of response." This is echoed by Thomas Talhelm, founder of Smart Air, a company that sells budget air purifiers. "It's very clear that things get kind of crazy whenever the air pollution gets bad," said Talhelm. "Our sales doubled every day for three days when the air was really bad in Shanghai." However, there have been concerns raised at the lack of regulation in this lucrative market. "There is no industry standard," said David-Experton. The Shanghai Municipal Bureau of Quality and Technical Supervision (SMBQTS) has previously said some companies that produce air purifiers are inaccurately describing the capabilities of their products. Recently there were calls for a national standard for anti-pollution face masks as some on the market claim to filter out PM2.5, tiny particulate pollution which is considered dangerous, but are not effective.

The anti-pollution market is growing rapidly, said Cheng. "As a whole the tide is rising, everyone is jumping in. It's kind of like green washing 10 years ago where everything was 'eco friendly'," he said. "It was a lot of marketing but there was not a lot of labelling control.do airfree air purifiers work "There is regulation but there is not a lot of enforcement around the regulation. air duct cleaning cedar city utahPeople will put their trust and money into something and it may not be justified." crc mass air flow sensor cleaner directionsIt is not just at the lower end of the market, said Cheng. "We see some very expensive systems and they are either employed incorrectly or they are just flat out ineffective."

As Talhelm discovered, the technology behind air purifiers is not complicated and some of the price tags of up to 16,000 RMB (£1,565) are not justified. He set up his company last September after he had found it difficult to buy a reasonably priced yet efficient air purifier to protect himself from the smog in Beijing. "I set out to buy a recommended one and realised it was $1,000. I couldn't justify the cost," he said. After carrying out research, Talhelm discovered that a HEPA filter attached to a fan is as efficient as some of the more expensive models he could not afford. "HEPA filters are not some crazy thing, in fact if you have a vacuum cleaner at home, it probably has a HEPA filter and you did not pay $1,000 for it." This week the Chinese premier Li Keqiang said China is "declaring war" on pollution, an indication of how serious the issue has become. While there were blue skies over Beijing as Li made his declaration, air pollution has become a persistant problem and last year the Chinese capital, Beijing, experienced a total of 189 polluted air days.

This declaration was significant, said Ma Jun, director of the Institute of Public and Environmental Affairs and one of China's most wellknown environmentalists. "There is great political will now to try and deal with the problem," he said. But economic growth "still trumps everything," he added. "Pollution is not just an environmental issue, it is an issue of livliehood and if unchecked it could become a political issue," Ma said. "There is an understanding that this is not just about public health and resources but also about social stability."February 18, 2015 Stanford engineers develop new air filter that could help Beijing residents breathe easily Stanford's Yi Cui and his students have turned a material commonly used in surgical gloves into a low-cost, highly efficient air filter. It could be used to improve facemasks and window screens, and maybe even scrub the exhaust from power plants. In the past few years, Yi Cui has made several business trips to China. Each time he has found himself choked by smog produced by automobiles and coal power plants.

After a few of these trips, Cui, an associate professor of materials science and engineering at Stanford, came up with an idea to clean the pollution. He and his graduate students set to work designing an inexpensive, efficient air filter that could ease the breathing for people in polluted cities. “My lab group really likes to solve problems, even if it’s something we’ve never worked on,” Cui said. “We think we could use this material for personal masks, window shades and maybe automobiles and industrial waste. It works really well, and it might be a game-changer.” The work is published in the current issue of the journal Nature Communications. This was the first time Cui’s group had designed an air filter – Cui’s work with nanomaterials focuses primarily on battery technology – so he and his students didn’t immediately look to materials that have traditionally been used in air filters. Instead, they looked for polymers that would have a strong attraction to the main components of smog, particularly particle matters that are smaller than 2.5 microns, known as PM2.5.

These pose the greatest risk to the human respiratory system and overall health; current filtration systems that can remove them from the air are very energy-intensive. It turned out that polyacrylonitrile (PAN), a material commonly used to make surgical gloves, met these requirements. “It was mostly by luck, but we found that PAN had the characteristics we were looking for, and it is breathtakingly strong,” said Po-Chun Hsu, co-author on the study and a graduate student in Cui’s lab. Using a technique called electrospinning, the researchers converted liquid PAN into spider-web-like fibers that are just a thousandth the diameter of a human hair.  In the study, the researchers approximated Beijing’s smog by flowing smoke from burning incense over different densities of the fiber, and later performed a field test in Beijing. The final material allows about 70 percent transparency and yet collects 99 percent of the particles. “The fiber just keeps accumulating particles, and can collect 10 times its own weight,” said Chong Liu, lead author on the paper and a graduate student in Cui’s lab.