Much of northern China remained blanketed under sand and dust on Wednesday although the worst sandstorm recorded in a decade was expected to gradually settle from Thursday as cold and wet weather fronts moved in.
Earlier this week the storm had caused pollution levels to spike in some of the country’s biggest cities, including Beijing, due to high levels of hazardous small particles in the air.
The National Meteorological Centre said a blue sandstorm alert – the lowest level of the four-tier warning system – remained in force on Wednesday across large areas of the country.
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“Parts of Xinjiang, Inner Mongolia, Qinghai, Gansu, Ningxia, Shaanxi, Shanxi, Hebei, Shandong, Henan and Hubei might see floating sand and dust on Wednesday, while sandstorms may occur in southern Xinjiang,” the centre said.
It advised the public to take precautions against heavy winds and dust by closing windows and doors and wearing masks.
The warning was downgraded from the yellow alert for “hazardous” levels of pollution issued on Monday, when 12 provinces were affected by the sandstorm blowing in from Mongolia.
The centre said that it was the most intense sandstorm in China in the past decade, covering an area of 3.8 million square kilometres (1.5 million square miles) – about 40 per cent of China’s land area.
Beijing’s air quality index was 258 at 4pm on Wednesday, which is considered very unhealthy, according to data from the National Environmental Monitoring Centre.
Levels of PM10, tiny particles that can penetrate deep inside the lungs, surpassed 390 micrograms per cubic metre by 4pm, about eight times the maximum daily average recommended by the World Health Organization.
Some northwestern cities have been shrouded by dust for three days. According to the World Air Quality Index project, a non-profit group that monitors pollution, the concentration of PM10 in many northwestern cities rose to over 500 micrograms per cubic metre.
Air quality in Lanzhou, the capital city of the northwestern province of Gansu, was rated as “hazardous” on the World Air Quality Index. The level of PM10 in the city exceeded the monitor’s maximum reading of 999 Wednesday morning.
Similarly, the air quality in Ordos city in Inner Mongolia also reached “hazardous” levels, with PM10 levels reaching 745 micrograms per cubic metre.
China has seen a steady decline in the number of sandstorms recorded, from 26 days a year during the 1950s to just three days last year, according to state news agency Xinhua.
Zhou Bing, head of the climate service at the National Meteorological Centre, said the decline was down to climate change, which had caused cold fronts to become weaker and less frequent.
“But as long as the conditions are met, sandstorms will still appear,” Zhou told Science and Technology Daily.
The centre predicted pollution in northern China would improve from Thursday but air quality would remain poor in the northwest of the country.
The heavy sandstorms also hit Mongolia hard, with 10 deaths and at least 341 people reported missing, according to Xinhua.
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