A:1. First of all, we should carefully observe whether the air filter itself is dark or black. If the air filter is obviously black, then the air filter should be replaced.
2.Similarly, air filters that are about to break down will be deflated. If we find such a phenomenon, we need to replace it.
3. The third point is to maintenance. If we find that there is a lot of dust around the air filter, then we need to clean it