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City PM2.5 density nearly 4 times China limit
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Shanghai experienced this autumn’s first heavily polluted day yesterday with the PM2.5 density nearly four times the national limit.
Serious air pollution saw most areas of the city enveloped in a haze early yesterday. The PM2.5 density rose to 240 in the morning, dropped to 160 by late afternoon but soared again in the evening.
By 8pm last night, it had peaked to a hazardous level of about 270 micrograms per cubic meter — nearly four times the national limit of 75.
PM2.5 refers to airborne particles which are smaller than 2.5 micrometers in diameter. They are the main cause of urban smog and are harmful to human health. Pedestrians put on masks to avoid the particles that can cause lung or cardiopulmonary health problems.
The average air quality index (AQI) was 221 by 6am and did not retreat throughout the day. It had climbed to 264 by midnight. Pudong’s Chuansha area recorded the highest AQI at 293.
The Shanghai Meteorological Bureau said the weather conditions — poor wind and lack of rain — made it difficult to disperse the air pollutants. But the conditions are expected to improve today because of heavy gusts of wind, the bureau said.
The Shanghai Education Commission asked schools to cancel outdoor activities yesterday.
Schools from kindergartens to high schools stopped morning exercise, sports sessions and other outdoor activities.
Fu Fang, principal of Weihai Road Kindergarten in Jing’an, said the kindergarten moved all outdoor activities indoors.
The Gao’an Road No.1 Primary School, whose first-grade students went autumn outing, changed their venue from Yuepu Park to Shanghai Science and Technology Museum.
Although the city has a two-level warning system for air pollution, neither was issued despite the heavy smog, prompting residents to doubt about the newly issued emergency measures.
According to the system, a warning for “heavy pollution” is issued when AQI reaches 200 for 12 hours, the momentary density for PM2.5 reaches 150 micrograms per cubic meter, and the situation shows no sign of improving in the following 24 hours.
The higher-level warning for “severe pollution” is raised when AQI reaches 300 for six hours, the momentary density for PM2.5 reaches 250 micrograms per cubic meter, and the situation remains unchanged or gets worse in the next 24 hours.
The local environment authorities explained that although the AQI topped 200, the momentary density for PM2.5 was only 144 at 3pm. There were also signs that the air quality would be better in the next 24 hours — a condition that did not fit the “heavy pollution” warning system.
But parents insisted that the warning system has loopholes, which led to the delay in schools being notified about the poor air quality. It gave parents no time to take protective measures against the pollution.
“This is unreasonable. By the time the three conditions are met, people will already be sick,” a young woman told Shanghai TV.
“The period should not be as long as 12 hours,” another pedestrian said. “If the warnings can be released sooner, authorities can take more efforts to reduce the emissions and protect the children.”
A woman said she hoped she could learn about the pollution earlier — before she send her child to the kindergarten.
When the warning for the “heavy pollution level” is issued, construction at work sites and discharge of pollutants by factories will be suspended. Vehicles carrying construction materials and burning of straw in the open air will be banned.
Schools will be told to stop classes. Seniors, children and people with heart and lung diseases will be advised to avoid outdoor activities, and other large-scale public activities will also be suspended.
For the “severe pollution level,” stricter measures will be in place. About 30 percent of official vehicles will be taken off the roads. Yellow-labeled, or heavily polluting vehicles, will be banned, while fireworks will not be permitted.
Besides, the Shanghai Environmental Monitoring Center will cooperate with the Shanghai Meteorological Bureau when issuing warnings that call for emergency measures to be put into effect.
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