A blue sun appears over Beijing on Sunday after its second sandstorm in a fortnight
A sandstorm that hit Beijing on Sunday morning pushed air pollution levels off the charts, turned the sky yellow and reduced the sun to a blue spot.
https://www.scmp.com/news/china/science/article/3127317/china-pollution-beijing-sandstorm-turns-sky-yellow-and-sun-blue
The storm was the second to hit the Chinese capital in less than two weeks and came after the Beijing Meteorological Bureau issued a yellow warning (the third highest) on Saturday. It also warned of high winds and advised citizens to stay at home if possible.
As of noon on Sunday, the city’s air quality index had stopped rising, after hitting the maximum reading of 500. Visibility in Beijing was reduced to less than 1,000 metres (3,300 feet).
On the Chinese social media platform Weibo, people shared pictures of the “blue sun”, a celestial phenomenon first seen in the skies above Beijing when the last sandstorm hit on March 15.
A Beijing Evening News report said the optical illusion was caused by “Rayleigh scattering”, which explains how the colours that make up sunlight are diffused by particles in the air.
The sandstorm was caused by strong winds carrying dust from drought-hit Mongolia and other parts of northwest China. Xinhua said Inner Mongolia, Shaanxi, Shanxi, Hebei, Tianjin, Liaoning and Jilin had also been affected by the storm on Sunday.
Wang Ji, director of the Beijing Climate Centre, was quoted as saying it was rare to have had two large sandstorms in less than two weeks. The Chinese capital recorded just one in the whole of last year.
