Beijing chokes on yellow dust during biggest sandstorm in almost a decade

The index measures the concentration of different pollutants in the air, the most important being PM 2.5. This harmful microscopic particle has a diameter of less than 2.5 micrometers and is considered particularly dangerous, as it can lodge deep in the lungs and pass to other organs and the bloodstream.

Beijing on Monday measured a maximum of 655 micrograms per cubic meter. The World Health Organization considers anything over 25 years old to be unsafe.

From Mongolia, the sandstorm gradually shifted south. Beijing saw concentrations of the largest PM 10 particles exceed 8,100 micrograms per cubic meter according to the city’s environmental monitoring center, prompting the Central Meteorological Observatory to issue a yellow alert for sandstorms, the second level in a four-color weather warning system.

Authorities advised citizens to go outside if possible, and the Beijing Municipal Education Commission on Monday called on schools and education committees to suspend outdoor activities.

But sandstorms have abated drastically; the annual number of days impacted by the sandstorm in Beijing fell from a high of 26 in the 1950s to just three days after 2010, according to Xinhua.

Sandstorms have also affected northern Hebei and Shanxi provinces, western Gansu and central and western Inner Mongolia. Monday, Xinhua said. Other parts of the country, including northern Xinjiang, are experiencing high levels of wind gusts. Sandstorms are expected to last until Tuesday.

Mongolia, located in northern mainland China, is experiencing strong cyclones, the weather administration said. Mongolian sand and dust have shifted east and south over northern regions of China, caused by high cold pressure at the back of the cyclone.