Introduction:
The question to be answered is what are main factors of air pollution in Beijing. Air pollution is a severe problem in Beijing and China now, it is always vital since the air quality is strongly related to the health of residents. The government has made several policies trying to reduce the air pollution, the air pollution is reduced but far from being solved. Finding the main factors of air pollution may not only reveal why it is so hard to be eliminated but also help the government to make real effective policies.