Strong thermal inversion, pollutant accumulation and weak cold air are the primary causes of the heavy air pollution that is forecast in Beijing for the coming days, the municipal environmental protection agency said Friday.
Heavy air pollution will strike the city on Saturday, with its concentration peaking on Monday. The air will gradually improve from Tuesday night when a cold front arrives.
Meteorologists said the middle atmosphere of northern China had a relatively high temperature this winter, and thermal inversion was more frequent and stronger than previous years, which resulted in poor dispersion of pollutants.
In addition, Beijing and many cities in the region are backed by mountains, which intensified the accumulation of pollutants generated in those cities and blown from plain regions.
Beijing has issued an orange alert for air pollution, which will come into effect from Saturday.
Beijing's air pollution emergency response office has ordered some manufacturers to reduce production and some construction sites to halt work. Heavily polluting vehicles and trucks carrying construction waste and dirt have been banned from roads.