A national standard for anti-smog masks is likely to be set next year, the Beijing Youth Daily reported, amid concerns that some masks on the market are not effective and leave citizens vulnerable to health risks.
The China Non-Wovens Industrial Textiles Association has finished the first draft of a proposal which it will submit to the national standards commission. It is hoped the standards could come into effect next year and help regulate the booming market.
Demand for the masks to keep out PM2.5 - the finest pollutant particles, which can cause the most harm to health - has soared since 2012, with 2.53 billion of them sold last year. Sales are expected to reach 3.92 billion next year.
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The US Environmental Protection Agency says the particles measuring less than 2.5 micrometres can be easily inhaled "deeply into the lungs", where they can damage tissues - a worrying fact in China, where PM2.5 readings often reach hazardous levels.
There is no national standard for civilian masks. Most industrial masks on the market follow US and European standards.
How to standardise PM2.5 masks was one of the main issues at a forum on air pollution management and prevention in Beijing on Wednesday.
The rapidly growing market is full of low-quality fakes that do not protect against PM2.5.
Blue skies reappeared over the capital yesterday after a week of thick smog. The US embassy's air quality monitor posted a "good" PM2.5 reading of 42 micrograms per cubic metre of air at 9am, a level which "poses little or no risk" to health. But the reading was still above the World Health Organisation's guideline of 25 micrograms per cubic metre.
The Beijing Municipal Environmental Monitoring Centre blogged that the city had a PM2.5 count of just 6 to 11 at 7am, due to cold air and a northerly wind.
"Today it's suitable to open your window and let the air in," the centre added.