The story appears on

Page A4

April 18, 2012

GET this page in PDF

Free for subscribers

View shopping cart

Related News

Home » Metro » Environment

Solutions sought on soot as city suffers 140 hazy days per year

ABOUT 140 days per year are hazy in Shanghai, environmental experts told a forum addressing PM2.5 pollution yesterday.

Hao Jiming, a member of the National Environmental Advisory Commission and vice director-general of the Chinese Society of Environmental Sciences, said PM2.5 density in most Chinese cities exceeds the World Health Organization Interim Target-1, the most lenient standard.

"In many cities, PM2.5 accounts for 50 percent of PM10. In Beijing, the percentage is more than 60 and in Shanghai it is about 60 percent," he said. "Compared with PM10, PM2.5 is more harmful to people's health."

PM2.5 affects air quality and visibility, causing haze, and poses major health risks as the particles are small enough to lodge deep in the lungs and even enter the bloodstream, leading to some premature deaths and long-term diseases.

Every year, there are about 100 hazy days in Beijing, 207 in Tianjin, 133 in Chongqing, 131 in Guangzhou and 239 in Chengdu, Hao said. He didn't specifically define what constitutes a hazy day.

He said developing public transportation and restricting the number of vehicles are the major solution for Shanghai to improve its air quality and reduce hazy days.

"It may take five to ten years for Shanghai to meet China's new standard on PM2.5 of 75 micrograms per cubic meter," he said.

The current air-quality measurement system includes only PM10, sulfur dioxide and nitrogen dioxide but not the stricter PM2.5 gauge, which monitors fine particles 2.5 microns or less in diameter.

Shanghai started to release PM2.5 measurement as a trial in March and plans to include PM2.5 data into the local air-quality measurement system in June. The number of days with excellent and good quality is expected to drop by 10 to 15 percent as a result.

Exhaust from motor vehicles and boats is the biggest source of local PM2.5 emissions, accounting for one-fourth of fine particles in the city's air.

Other major components are the spreading of sandstorms from northern China and local sources that include industrial processes like chemical factories, industrial sprays, industrial boilers, power plants and flying dirt from construction sites, roads and stocking yards.

Residences contribute with kitchen smoke, laundry and painting, as do agricultural practices like straw burning, fertilizer use and livestock farming.

Hao said at the forum that the Yangtze River Delta region, of which Shanghai is a part, has its regional characteristics on fine particle pollution.


Copyright © 1999- Shanghai Daily. All rights reserved.Preferably viewed with Internet Explorer 8 or newer browsers.

沪公网安备 31010602000204号

Email this to your friend