According to the video and related information released by netizens, the train is the K5302 train from Taiyuan, Shanxi to Datong. After the train entered the Yanmen Pass tunnel, dust appeared in the carriage, and many passengers covered their noses or faces with clothes. Some travelers showed off the black dust on their hands, faces and small tables. Many netizens said that the black dust in the car and body was suspected to be coal ash.

The reporter sent a private message to many netizens who sent videos, but no response was received yet. On the afternoon of the 8th, the situation statement released by the Taitie Taiyuan Passenger Section showed that the K5302 train is a non-air-conditioned passenger train. In order to ensure the safety of passengers' passengers and ventilation in the car, the train windows can be opened at a height of 10-15 cm. The Yanmen Pass Tunnel passed by this train is a long tunnel, with dust easily accumulated and it is difficult to clean. On the same day, before the train entered the tunnel, the staff prompted that the windows were closed and the inspection was not in place, causing dust in the tunnel to enter the carriage due to the airflow, causing discomfort in the passenger environment.
Source: Jimu News