1st Ld-Writethru: Sandstorms sweep through northern China

A sandstorm swept over much of north China including Beijing on Thursday, turning the sky yellow and obscuring visibility.

The city's meteorological center issued a blue alert for sandstorms Thursday morning, forecasting winds to carry sand and dust across the capital. Many pedestrians in downtown Beijing were seen wearing protective masks.

Most monitoring stations in the city showed PM10 and PM2.5 readings of more than 1,000 micrograms per cubic meter and over 400 micrograms per cubic meter respectively as of Thursday at noon, according to data from Beijing Municipal Environmental Monitoring Center.

Visibility plummeted to as low as one kilometer in many parts of Beijing and it is expected to fall further.

Neighboring Tianjin Municipality was also hit by dust and sand, which darkened the sky and slowed traffic.

"The sky turned gray and the smell of dust and sand crept into my room in the morning. My child felt uncomfortable after staying outdoors for a while," said a Tianjin resident surnamed Liu.

Traffic police advised drivers to slow down and turn on their fog lights when driving.

According to Lu Huanzhen, forecaster at the Tianjin meteorological station, the sandstorm in Tianjin is expected to disperse on Friday night.

Parts of Beijing, as well as Gansu, Hebei, Heilongjiang, Jilin, Shaanxi and Shanxi provinces and the autonomous regions of Inner Mongolia, Ningxia and Xinjiang will see sandstorms from Thursday to Friday, said the National Meteorological Center.

Zhu Jiang, head of the Institute of Atmospheric Physics of the Chinese Academy of Sciences, said the sandstorms originated in Mongolia.

China has a four-tier color-coded system for severe weather, with red being the most serious, followed by orange, yellow and blue. Endi