Main categories: 
There are three types of air filtration: inertia, filtration and oil bath:　　
Inertia: Since the density of impurities is higher than that of air, when the impurities rotate or make sharp turns with the air, the centrifugal inertial force can separate the impurities from the airflow.
Filtering type: guide the air to flow through the metal filter screen or filter paper, etc., to block impurities and adhere to the filter element.
Oil bath type: There is an oil pan at the bottom of the air filter, which uses the sharp rotation of the airflow to impact the oil, separating impurities and sticking in the oil, and the agitated oil mist droplets flow through the filter element with the airflow and adhere to the filter element. When the air flows through the filter element, it can further adsorb impurities, so as to achieve the purpose of filtration.

Replacement cycle: 　
It is generally recommended that customers replace it every 15,000 kilometers.
Vehicles that often work in harsh environments should be replaced once no more than 10,000 kilometers. (Deserts, construction sites, etc.)
The service life of the air filter is 30,000 kilometers for cars and 80,000 kilometers for commercial vehicles.