The air filter box houses the air filter, a crucial part of the car's air intake system. The air filter improves the performance of the engine, enabling it to work as efficiently as possible whilst increasing the life of the engine.
Air needs to be as clean as possible before it mixes with the fuel and burns in the cylinders of the car's engine. The air filter protects the engine, by filtering the air coming into the engine, collecting dust and other particles before they can get into the engine and cause damage. The air filter also helps to silence the engine to a degree, in that the sound is absorbed by the filter.
The air filter box is connected to the car's air intake, allowing the air filter to catch particles and filter the air at the point the air enters the air induction system. The air filter box assists also in the direction of air flow.
If the air filter box gets damaged, it's possible that some air will be entering the car's engine without being filtered which is not good. A broken air filter box could compromise the air filter it is meant to be protecting. Any damage to the air filter can cause serious problems that can lead to engine damage if not addressed.