The engine sucks in air. If the air has dust in it, it will scratch the engine. So the air filter cleans the air.

A supercharger.

An air intake filter is what blocks dust particles from entering into you engine. It is an air purifier which cleans the air your engine takes in.

In automotive engine terms, the air intake system would include everything between and including the air filter housing to the heads on the engine. The automotive HVAC (Heating, Ventilation and Air Conditioning) system also has an air intake system. This is where fresh air or recycled cabin air circulates in the cabin area.

On a 2004 Ford Freestar ( 3.9 and 4.2 )

The Mass Air Flow Sensor is between the engine air filter and the engine

air intake tube . It is INSIDE the removable section of the engine air filter

housing