Dirty air will be the norm for 5 days

Beijing will experience five days of poor air quality partly caused by heating systems being turned on, officials announced on Tuesday.

Pollution is expected to be moderate to severe in the next two days, but may drop a little due to possible rain on Friday before rising again during the weekend, Beijing Environmental Protection Bureau has forecast.

"Pollution caused by heating systems is one significant factor, while high humidity and little wind are unfavorable weather conditions for the diffusion of pollutants," said Zhang Dawei, director of the bureau's municipal environmental monitoring center. "But we are expecting that haze and fog will be blown away when the wind comes next Monday."