Trees planted to form a barricade to pollution (3)

"The channel for pollution in the past has turned into a natural protective screen, intercepting the dust before it can go further," Wang Shu-qin said. "The difference will be felt as soon as this project is completed."

The greenbelts will also render the community a more pleasant place to live, she said.

Beijing has set up 35 air-monitoring stations and has started releasing reports in real time on PM2.5 density, as well as the air's concentration of sulfur dioxide, nitrogen dioxide and PM10.

One of the stations, in Changping, another northwestern district of the capital, is charged with studying how cities and suburbs near Beijing add to the pollution in the capital.

"We used to have some 50 coal yards in the district, and that made the city's air quality worse, especially in the winter," said Wang Xia, deputy director of the district's afforestation office. "About 30 of the coal yards have been moved out and the remaining 20 are to be cleared away in the near future and replaced using afforestation. So it's believed that the air quality will improve noticeably."