Snow, which fell in most parts of northern China over the weekend, will continue on Monday, according to weather authorities. Snow grounded flights and delayed high-speed trains, but also helped to clean the air.

The new year's first widespread snowfall started on Saturday night, covering almost all provinces, autonomous regions and municipalities in northern China, according to the National Meteorological Center, with snow up to 8 centimeters deep in parts of Hebei province and Beijing.

Snow will continue in these areas, with parts of the Shandong Peninsula expected to receive heavy snow, the center forecast on Sunday.

Snow helped clear the smog that shrouded many parts of North China in the past few days, the center said, but it issued a warning against potential travel risks due to snow and freezing.

Beijing Capital International Airport canceled at least 115 flights on Sunday, including 17 international flights, its website said. The airport had 48 snowplows to clear the runways, it said.

Activities at airports in Datong, Shanxi province, and Hohhot, the Inner Mongolia autonomous region, were suspended until noon on Sunday.

The normally punctual high-speed trains ran at lower speeds for safety, causing many delays.

At least 32 trains on the Beijing-Shanghai and Jinan-Qingdao high-speed railways had delays of at least five minutes on Sunday in Shandong province, according to Jinan railways bureau.

Passengers stranded at airports and railway stations complained on Sina Weibo, a popular micro-blogging platform.

"Just now the airport announced my flight would be delayed for another four hours until 8 pm," wrote a netizen going by the name Li Xiaowa, who was waiting at Beijing Capital International Airport.

"Many high-speed trains have been delayed, especially those bound for Shanghai and Hangzhou," said another micro blogger named 508RXH.

Although transportation was disrupted by the snow, air quality improved temporarily in many cities.

The pollutants in Beijing's air were significantly diminished on Sunday, and air quality in most parts of city was graded as good or slightly polluted. The concentration of PM2.5 - particles of 2.5 microns or smaller - fell to around 100 micrograms per cubic meter in most parts of the city, according to China National Environmental Monitoring Center.

By way of comparison, PM2.5 concentration reached as high as 500 micrograms per cubic meter in some parts of Beijing on Friday before the snow, when the city was shrouded in thick smog.

PM2.5 is considered more dangerous than larger particles as they can penetrate into the lungs and cause many diseases.

The capital's air quality will remain relatively good for the next few days because of the snow, according to the Beijing Municipal Environmental Monitoring Center.

In Shijiazhuang, capital of Hebei, concentration of PM2.5 was reduced to about 100 micrograms per cubic meter on Sunday - from 300 on Saturday - after heavy snow.

"The reduction of PM2.5 in the air on Sunday is due to the snow, which clears the fine particles from the air and washes them away," said a chief weather forecaster at China Meteorological Administration who wished to remain anonymous.

"In addition to snow or rain, Beijing largely depends on wind to blow away pollutants in the air," he said.

wangxiaodong@chinadaily.com.cn

(China Daily 01/21/2013 page3)