A new forecasting system is now able to tell the air quality at each Olympic venue 72 hours in advance, Beijing's environmental authority and developers of the system said.

"In our forecast, we divide the city into one-square-kilometer grids which include Olympic venues," said Wang Zifa, a research fellow at the institute of atmospheric physics, Chinese Academy of Sciences, developer of the system.

The now operational computer system can assess how after being emitted from a source, pollutants flow in the air, undergo what kind of physical change and chemical reaction, generate what kind of secondary pollutant and its density, according to Wang.

"Our multiple technological means can monitor Beijing's neighbors such as Hebei and Tianjin, and analyze the forming of pollutants in the areas so as to make the forecast more precise."

Wang said the development of the comprehensive forecasting system originated in the United States and the European Union.

The forecasts will enable environmental protection authorities to have enough time to take emergency measures in case of extreme weather conditions, such as continuous days of little wind that are unfavorable for the dispersing of pollutants.

Beijing has spent more than 120 billion yuan (US$17.3 billion) to contain air pollution since 1998. The city has expanded public transport, tested a temporary traffic ban that is to be adopted during the Games and relocated polluting factories.

The surrounding areas -- Tianjin, Hebei, Shanxi and Shandong and Inner Mongolia -- are lending a hand to the capital to help achieve anti-pollution goals. They have taken such measures as the closure of major polluters, removal of outmoded taxi cabs and treatment of gas stations to let them capture emitted harmful chemicals.

(Xinhua News Agency June 14, 2008)