Many new vehicles have a cabin air filter to clean the air inside your car. These filters remove dust, pollen and other pollutants from the air you are breathing while driving along. These filters not only clean the air, but help keep the interior cleaner by filtering out the dust that the HVAC (Heating, Ventilation and Air Conditioning) system would normally just blow into and around the insides of your car.
These cabin air filters are located in the HVAC case, most often behind the dashboard of the vehicle. Some are located under the hood of the vehicle, a check of your owners manual will tell you for sure. All of the air entering the vehicle, when the windows are closed of course, comes through the HVAC system. The heater, defroster, vent and air conditioner all get their air supply filtered through the cabin filter.
The cabin filter is much like the air filter your engine uses to keep its air supply clean. Pleated paper or fabric is mounted to a frame which is then fitted into the HVAC case. These cabin filters can also be electrostatically charged to further enhance their air filtering abilities by attracting more pollutants.
The filter itself is strategically placed in the air stream of the HVAC system so that while filtering the air efficiently, it is also easily accessible for maintenance. The fan, or fans, of the HVAC system pulls outside air into the vehicle, pushing it through the heating or air conditioning elements, regulating its temperature, then blowing it through the filter before it enters the cabin. In the even that the air conditioning system is in recirculate mode, that is when the system is not pulling outside air into the cabin, the air is still blown through the filter before re-entering the cabin area.
These cabin filters improve the air quality inside your vehicle, and provide a cleaner, more healthful driving environment.