Beijing and much of northern China awoke to suffocating sand and dust on Monday as a winter sandstorm drove air pollution off the charts.
A thick cloud of dust blanketed the Chinese capital, where the air quality index of PM10 — pollution particles less than 10 microns in diameter that can penetrate through the nose and reach the lungs — reached 999, meaning it exceeded the top of the scale far beyond the point considered hazardous to health.
Levels of PM10 particles exceeded 561 micrograms per cubic meter as of 8 a.m., according to the Beijing Environmental Monitoring Center. That number is more than 10 times the daily average guideline of 45 micrograms per cubic meter set by the World Health Organization.
Sandstorms used to hit Beijing regularly in spring, but less so in winter. The last time there was a sandstorm this late in the year was in 2015.
The sandstorm originated in Mongolia and gradually moved south. Early Monday morning, the Central Meteorological Observatory issued a blue alert for sandstorms – the lowest level in a four-tier warning system – for much of northern China, from the eastern city of Tianjin to the Xinjiang region in the far west.
Mongolia, which lies north of mainland China, is experiencing strong cyclones, according to the weather agency. Sand and dust from Mongolia have been moving east and south across China’s northern regions, carried by the cold high pressure behind the cyclones.
Sandstorms also hit northern Hebei and Shanxi provinces, western Gansu, and central and western Inner Mongolia on Monday, state-run Xinhua news agency said. Other parts of the country, including northern Xinjiang, are seeing strong gusts of wind. The sandstorms are expected to continue through Tuesday.
In the spring of 2021, Beijing was hit by the biggest sandstorm in almost a decade, turning the sky an eerie shade of orange. For the past few decades, there have been at least two rounds of sandstorms every May, according to Xinhua. The frequency and severity of sandstorms was due in part to drought, increasing population pressures, and poor replanting progress, leading to rapid desertification in the north and northwest.
But sandstorms have decreased dramatically since then; The annual number of days affected by sandstorms in Beijing fell from a peak of 26 in the 1950s to just three days after 2010, Xinhua reported.
Since 2000, the Chinese government has invested billions of dollars in sandstorm prevention. Authorities have launched various reforestation and ecological projects and installed satellites to monitor sandstorms and warn weather authorities in advance.