Impurities such as dust, pollution, and other dirt must be removed from both the air and the fuel. Gasoline is filtered several times before it reaches your engine, but the air is simply pulled in from around the vehicle, which is why an extremely efficient and clean air filter is necessary.
When the filter is dirty, some fuel doesn’t burn, the engine becomes less efficient, and both the engine and exhaust system get clogged.
If you drive where there is a lot of dust, pollution or pollen in the air, your engine air filter will get dirty more quickly and need to be changed sooner.