BEIJING, Oct. 3 (Xinhua) -- Heavy air pollution continues to hit Beijing and surrounding areas and will not disperse until Tuesday night, the city's weather bureau said Monday.
According to the bureau, the concentration of hazardous fine particulate matter known as PM2.5 in Beijing was between 100 and 200 micrograms per cubic meter, indicating moderate pollution.
The city issued its first yellow alert for air pollution in the second half of this year on Sunday, triggering restrictions on work at construction sites, outdoor barbecues and burning straw.
Meteorological experts expect north China to face more smog in autumn and winter, given unfavorable weather conditions this year.
China has a four-tier color-coded system for severe weather, with red being the most serious, followed by orange, yellow and blue.