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December 26, 2011

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Home » Metro » Environment

Shanghai's air falls below standard

Shanghai has failed to meet a proposed air quality standard for the past five years, according to the city's environment watchdog.

Shanghai Environment Monitoring Center data showed that the average density of particles less than 2.5 micrometers in diameter was higher than the proposed PM2.5 standard every year since the pilot study began in 2005.

PM2.5 refers to small particles that affect air quality and visibility.

Health experts say they pose major risks as they are small enough to lodge deep in the lungs and even enter the bloodstream, leading to premature death and long-term diseases.

Currently, Chinese cities adopt the less sensitive PM10 standard in reporting air quality.

The practice could lead to the underrating of air pollution with figures at odds with people's perceptions, experts said.

Weather experts say the smaller particles are to blame for worsening air pollution in a number of China's major cities. Last year, for example, both Shanghai and Beijing experienced "hazy" days for up to six months.

The particles are the product of combustion from motor vehicles, power plants, residential wood burning, forest fires, agricultural burning and some industrial processes, according to environmental experts.

The Shanghai center's study showed that the average density of those smaller particles in the air was 0.044 to 0.053 milligrams per cubic meter for the past five years in the city compared to the proposed standard that will require such particles to be controlled to under 0.035 milligrams.

The report showed that in 2010 the daily PM2.5 density in the air above Shanghai ranged from 0.007mg to 0.245mg. The proposed national standard has a daily limit of 0.075mg.

However, the report indicated that the density of PM2.5 in the air was dropping year by year, and the city's environment watchdog said on its website that air quality would continue to improve through PM2.5 monitoring, cutting pollution from motor vehicles and factories, and developing clean energies.

The watchdog's data was collected from 24 monitoring sites across the city.

The stricter PM2.5 standard is to be introduced throughout the country over the next five years, with Shanghai and Beijing starting to use it next year, the Ministry of Environmental Protection has said.

Meanwhile, Shanghai is expected to suffer slight pollution today, but air quality should improve in the afternoon, the center said.

The city has experienced "dusty haze" conditions for about 155 days on average in recent years, according to the city's meteorological bureau.


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