Li Xinmin, an official with the Ministry of Environmental Protection has urged hastening the national elimination of high-emission vehicles to help curb urban air pollution.
He said, "The automobile emissions have become main sources of air pollution in Chinese large and medium-sized cities. High-emission cars and trucks only make up 28% of all automobiles in China, but they are responsible for 75% of the pollutant emissions."
Automobiles which fail to meet the National Emission Standard I are listed as high-emission vehicles in China. The Standard I, equivalent to the Euro I standard, allows an average petrol sedan to emit a maximum of 2.7 grams of carbon monoxide a kilometer, whereas Standard IV requires less than 1 gram of carbon monoxide and 0.08 gram of nitrogen oxide per kilometer.
China introduced Standards I, II and III respectively in 2000, 2005, and 2007. Standard IV is scheduled to be adopted nationwide in 2010.
China had more than 64 million automobiles by the end of 2008, among which 18 million were high-emission vehicles.
During the Olympics and Paralympics last year, Beijing limited the use of most vehicles through an odd-even license plate system. The initiative took 45% of the cars off the roads and helped keep skies clean.