An Overview of Air Pollutants Inside the Subway and the Influencing Factors.

In recent years, air pollution has become one of the most basic and widespread problems in many big cities. This problem is especially evident in closed, busy urban environments like the subway. Air pollutants inside the subway can endanger the health of passengers and employees and negatively affect their quality of life. This research reviewed the air pollutants inside the Bangkok, Shanghai, and Munich subways and the influencing factors. The control and management strategies for these pollutants were also discussed.