The bureau will work to reduce the density of suspended particles from the current 150 micrograms per cubic meter to 100 micrograms by 2008.

Bureau Director Shi Hanmin Wednesday told the Beijing Municipal People's Political Consultative Conference: "Pollution from suspended particles has become a bottleneck in improving the capital's environment."

On 89 percent of days last year, suspended particles were the main pollutant in the city.

Dust from the capital's many construction sites is a major cause of the pollution, said Shi.

Construction sites covered 96 million square meters of the city last year.

"Serious dust problems have been caused on the sites, as well as in the streets," Shi pointed out.

The Beijing municipal government said various measures would be adopted to control air pollution, including that caused by dust.

The Beijing Municipal Construction Committee requires building firms to establish a special fund to control dust pollution in their bids for projects.

Barriers must be set up around construction sites and vehicles used there must be cleaned before they are driven from the sites.

Construction sites that do not meet the environmental requirements are listed as such in the city's credit information system.

Vehicles transporting garbage, mud and stones are forbidden from entering the area within the Fifth Ring Road unless they are airtight.

"Furthermore, suspended particles are not simply dust but a complex issue involving other elements," said Shi.

Suspended particles come from the burning of coal, vehicle discharges and large construction sites, as well as from the concentrated population and architecture, he said.

The weather and location of Beijing also influence pollution from suspended particles, he said.

"It is difficult for pollutants to spread if there is no wind or rain in Beijing, unlike in coastal cities such as Shanghai," the official said.

(China Daily April 3, 2003)