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Cold front to clear city's air

THE dense haze that has shrouded Shanghai for the past few days is set to continue today as smog lingers in large parts of east and central China.

But the sky should clear tomorrow with the arrival of a cold front from the north and the air quality will be between "good" and "lightly polluted," the Shanghai Environmental Monitoring Center said yesterday.

The center issued an air pollution alert at 7:39am yesterday when the city's hourly PM2.5 index reached 96.1 micrograms per cubic meter. It urged people with cardiovascular and respiratory diseases to avoid outdoor activities.

The downtown density of PM2.5 pollutants, particles smaller than 2.5 micrometers in diameter, began to climb at 6am and reached 118 at 10am.

The average reading over the previous 24 hours was 116.2 at 10am, compared with the nation's safe standard of 75.

After 10am, the density began to drop and was 77.5 at 5pm.

While Shanghai was still experiencing poor quality air, Beijing was able to breathe more easily yesterday.

After five consecutive days of heavy to severe pollution, the capital's air quality was deemed "good," partly thanks to a fall of snow.

By 9am, visibility in the capital's streets had improved to a kilometer from less than 200 meters in previous days. The air was noticeably cleaner and many residents chose to leave their masks at home when they went out.

All monitoring stations' PM2.5 readings had dropped significantly. The Dongsi station in eastern Beijing recorded 64 at 10am yesterday, while the average density over the previous 24 hours was 129. At 10am on Sunday, the previous 24 hours reading of PM2.5 at the station was 559. Monday's 10am figure was 284.

The Beijing Environmental Monitoring Center said the density of fine particles started to drop from late Monday because of falling temperatures and snow.

At 7am yesterday, all monitoring stations in the city reported an hourly PM2.5 density between 50 and 70.

Since Thursday evening, the hourly density of PM2.5 in most of Beijing had surpassed 300 and many monitoring stations recorded over 700 on Saturday.

With the arrival of a cold front in the capital city last night, the wind was expected to blow away local pollutants, further improving air quality, the center said.

Coal burning, vehicle exhaust and factory emissions, wind-blown dust and the still weather conditions have been blamed for the city's latest round of serious pollution.


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