As the northern hemisphere entered winter season, public heating supply in northern China was in full swing again. At the same time, air pollution dramatically increased at this time of the year in northern China.
There have been discussions around the cause of air pollution. Many people believe that heating supply is the one influence factor since coal is the major power source for heating companies in China.
Actually, the formation of air pollution is very complicated. It is a combination of pollutants including particulate matters, nitrates, sulfates, ammonium, VOCs and more. Low quality coal burning with high concentration of sulfur is one of the causes for air pollution. Pollutants also come from vehicle exhaust emission, cooking fumes, industrial emission and other sources.
As to air pollution in northern China recently, weather and geographical factors as well contributed to the pollution scale. In the cold winter, weather condition is basically stable in northern China. Near ground atmosphere is stable along with still wind flow and less air circulation. Therefore, polluted air cannot be diluted quickly enough and PM 2.5 index exceeds the range.
However, air pollutant can be forecasted and preventions have been taken based on the study of weather and atmosphere. Chinese government departments are well aware of this situation and are working hard to improve it now.