Chen Liangyao displays the filter of his DIY ventilation device. [Wang Juliang/for China Daily]

Home air purifier sales and prices have soared to sky-high levels in pace with China's air pollution.

But Chen Liangyao has taken a different - and seemingly cheaper - tact.

The Fudan University professor has developed a do-it-yourself ventilation system that improves indoor air quality.

It's his solution to the fact that studies show shutting the windows doesn't keep all the smog out on heavily polluted days. Yet people are advised to stay indoors when the smog is thickest.

A plus is that Chen's setup also clears odors that hover when the windows are closed.

The 63-year-old Department of Optical Science and Engineering professor spent 7,000 yuan ($1,500) to install the system in his Shanghai apartment in 1999.

That was long before the Shanghai Environmental Monitoring Center's air quality index that measures pollution surged to a record 482 on Dec 6 of last year.

"It allows fresh air in but blocks small particles," he explains.

Chen's invention has captured media attention.

But he believes he's simply a step ahead of where we're all going - or at least should be.

"Every member of and force in society should advance indoor air quality," he says.

"All new residences should be built with a proper air-ventilation system. We can prevent respiratory diseases this way."

Chen got the idea when he studied in the United States. Ventilation systems are common in US houses but rare in China, he explains.