It can be replaced in advance. The replacement cycle of the car air filter is generally 20,000 kilometers or half a year. If the car owner drives at high speed for a long time, the replacement cycle can be appropriately extended. If the car owner often drives on some roads with poor road conditions, it should be replaced once within 10,000 kilometers.

An air filter is a device that purifies the air:
1. If the dust, sand and various impurities in the air directly enter the engine cylinder for combustion, they will accelerate the wear and tear of the engine heat, thereby reducing the service life of the engine and even causing serious damage to the engine;
2. The filter element of the air filter is divided into two types: dry filter element and wet filter element. The dry filter is also the most frequently used in our car, and its material is filter paper or non-woven fabric. In order to increase the air passage area, most of the filter elements are processed with many small wrinkles;
3. When the filter element is slightly damaged, it can be blown clean. When the filter element is seriously damaged, it should be replaced with a new one in time.

The effect of not replacing the air filter for a long time:
1. Air filter element: The air filter element can block the dust and road dust entering the engine. These hard particles will cause internal wear of the engine, cause scratches on the cylinder surface, adhere to the surfaces of closely fitted parts, and cause surface wear on exposed and lubricated parts;
2. Air-conditioning filter element: The main component of air-conditioning filter element is activated carbon, which is an efficient adsorption material. As early as the "World War I", it was used in gas masks. And now activated carbon is widely used in car or indoor air purification;
3. Activated carbon is a porous carbonaceous material, and its developed void structure makes it have a large surface area, so it is easy to fully contact with toxic and harmful gases in the air. The strong adsorption force field around the pores of the activated carbon will immediately suck the toxic gas molecules into the pores, so the activated carbon has a strong adsorption capacity.