Customers choose masks from a nearly empty shelf at a store in Beijing on Wednesday. Masks and air purifiers have been flying off the shelves in the capital because of heavy air pollution that began to shroud the city from early last week. Liu Zhe / China Daily

In an attempt to stop her family from breathing polluted air, Christina Wang, the mother of a 3-month-old in Beijing, bought her second air purifier in two months.

"We put one in the living room and another in the baby's room," said Wang.

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She said she shuts all the windows and washes her hands, face and nose every time she returns home.

Wang is among many people grappling with persistent smog in huge urban clusters in North and East China, where people are rushing to buy products to purify the air.

Most of the air purifiers at a Beijing supermarket run by Carrefour SA were sold out when a China Daily reporter stopped by.

"Most of the purchases are for household use," said a store manager, who declined to be identified.

"Sales of air purifiers doubled from the same period last year. We're introducing more brands to meet rising demand."

In the past week, sales of air purifiers in severely affected cities including Beijing and Tianjin grew 500 percent, compared with the previous week when the smog was not serious, according to Suning Commerce Group Co Ltd, a leading home appliance retailer.

According to China Market Monitor Co Ltd, sales of air purifiers last year reached 2.4 million units, up 90.5 percent year-on-year. In value terms, sales grew 106 percent to 5.6 billion yuan ($918 million).

Air purifiers offering multiple layers of filters have become more popular. Sales of those with five layers were up 191 percent, according to China Monitor.

Foreign brands account for more than 80 percent of the market. Those priced between 1,000 yuan and 3,000 yuan are most popular.

The company has forecast that sales of air purifiers will reach 3.6 million units this year, with a retail value of 9 billion yuan.

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