On the premise of ensuring safety, the aircraft shall use the maximum ventilation during flight; During ground operation, the aircraft auxiliary power system is used for ventilation. At present, almost all aircrafts carrying passengers in China are equipped with HEPA filters, and the filtering efficiency of 0.3 μ m pollution particles can reach 99.9% or more.

The full name of HEPA is High Efficiency Particle Air Filter, which is often translated into Chinese as high-efficiency air filter. HEPA was born in the 1940s and was initially used to prevent the spread of radioactive pollutants in the air. In the 1950s, HEPA gradually became the proper name of high efficiency filter. Today, HEPA technology has been developed maturely and widely used in aviation, pharmaceutical processing, nuclear power, computer chips and many other fields.