It's possible to have sandstorms in early summer in Beijing under certain conditions, an expert said on Monday as the municipal meteorological observatory issued a blue alert for extreme weather.
When most people were still in bed at around 5:30 am, the observatory issued a blue alarm for both dust and wind. It said PM10 readings exceeded 800 micrograms per cubic meter at the morning peak.
The dust gradually faded and the authorities lifted the alert at 10:30 am when visibility improved.
Many people believe that sandstorms occur in spring in the capital and seldom in summer. However, senior engineer Guo Jianxing at the Beijing meteorological service center, said that low rainfall this year in the central and eastern parts of the Inner Mongolia autonomous region, as well as a low pressure system, are responsible for the sand that was blown to Beijing on the northwest wind.
Sandstorms typically happen from March to May, he said.
The capital has encountered sandy weather several times this year. The most serious one was on March 28, when PM10 readings came in at 3,157 micrograms per cubic meter in the Dingling area of northwestern Beijing.
Experts are reminding the public to wear masks for protection during sandstorms. Children, the elderly and the infirm should keep outdoor time to a minimum.
China has a four-tier color code for severe weather, with red being the most serious, followed by orange, yellow and blue.
