As a closed indoor space, the cabin body also has its own "air conditioner", but in the industry this system is called "environmental control system", or environmental control system for short.

And many passengers also think that the plane is a confined space, and may not pay attention to the air circulation and filtration system of the cabin before experiencing the new crown epidemic.

With the gradual increase in the age of the aircraft, and the damage to the air-conditioning system caused by catkins and air pollution in certain seasons, the performance of the air-conditioning system will be attenuated or even deteriorated when the new aircraft is put into use for about two years.