Ni Huan, a woman in Shanghai, stands on her eco-friendly balcony. [Shanghai Morning Post]

Ni Huan, a woman in Shanghai, has created a self-made air purifier which can filter particle pollutants including PM2.5, the major cause of smog, in her home.

The air purifier is composed simply of an electric fan, a filter plate and a piece of string.

"The fan cost 80 yuan (U.S. $13), which I had planned to throw away. The filter plate was bought online, also at 80 yuan (U.S. $13). The string is no more than 20 yuan (U.S. $3). Altogether, they cost less than 200 yuan (U.S. 32)," said Ni whilst showing off her gadget.

She said that she learned from an ecological protection group how to make this DIY air purifier.

The facility worked 24/7 when heavy fog swept the city a few days ago.

"Look at the filter plate; its color is getting black, which means it does quite well in absorbing particles," she said, pointing to the slimline disc.

The theory behind the air purifier is simple, Ni said, explaining that the fan moves the air indoor through the filter plate, which then filters or absorbs the pollutants.

Although it is simple, it works. "I change the filter plate every two months. It can get 'black' more quickly in winter," she said.

A normal air purifier sells for several thousand yuan (at least U.S. $160). With complicated buttons, the elderly often find them hard to operate. However, the DIY air purifier can be operated simply with the power-on and off button.

The filter plate mainly works to remove PM 2.5 particle pollutants, with little effect on other forms of airborne nasties.

"It is cost-effective for home use," said Ni, "But it is a shame that the filter plate can only be bought via an environmental protection organization online."

Ni is an enthusiast of green living. Apart from the DIY air cleaner, she also installs solar panels on her balcony to generate electricity. She uses a green energy car and keeps a compost bin for kitchen waste in her home.

"My life is low carbon and I wish this could offer some inspiration to those who endorse eco-protection," she said while leading nearly a dozen visitors to tour her balcony.

(Source: Shanghai Morning Post/Translated and edited by Women of China

Editor: Kate Wu（wonmen of china)