The Beijing-Tianjin-Hebei region is expected to see heavy air pollution for a week, starting on Friday, because of unfavorable conditions for the dispersal of pollutants, according to the Ministry of Environmental Protection.

The concentration of PM2.5 will climb to 200 micrograms per cubic meter or higher in central and southern parts of the region, it said.

The capital is likely to see moderate to heavy air pollution through Thursday. Some areas in Shanxi, Shandong and Henan provinces will also be affected, it said.

Air pollution will peak from Sunday to Wednesday, when conditions turn even more unfavorable. Another one or two bouts of smog may strike the region again later this month, the ministry said.

PM2.5 refers to dangerous particulate matter with a diameter of less than 2.5 microns that can enter the bloodstream via the lungs.

The air pollution is created by the convergence of coal burning in the ongoing heating season in the northern part of the country with the restart of factory production after Spring Festival, taking the discharge of air pollutants to a very high level, the ministry said.

It also said the structures of industry, energy consumption and transportation in the region have not been changed completely, so heavy air pollution is likely to happen when unfavorable meteorological conditions exist.

The Beijing-Tianjin-Hebei region is prone to air pollution in March because of the normal high humidity and stable atmosphere, said Chai Fahe, senior researcher at the Chinese Research Academy of Environmental Sciences.

The ministry noted that the region has been hit in March by heavy air pollution for three consecutive years.

It said it will pay close attention to the situation and provide solutions for local governments in time to reduce pollution's effect on people's health. A national joint research center on air pollution will look into the causes of the current pollution and make the results public.

Bad air is expected to be dispersed by rain and a cold weather front around March 16.

Recent research has found that the 28 major cities in the Beijing-Tianjin-Hebei cluster discharge 10 percent of all sulfur dioxide and volatile organic compounds, as well as 15 percent of nitric oxide and primary particulates, though they cover no more than 3 percent of the country's territory. Coal burning, industrial production and vehicles are major contributors to PM2.5 in the region as well.

Hou Liqiang contributed to this story.