Most American motorists know they need to change the oil filter on their car or truck every 3,000 miles or as their owner’s manual indicates. But when it comes to cabin filters, few among us even know about its presence in our vehicles, let alone why or how frequently it needs to be changed.

“Many drivers simply have no idea that their vehicle is equipped with a cabin filter, where it is, or what it does,” said Rob Backode, senior product manager for Robert Bosch Corporation. "Yet the cabin filter is essential to a good driving experience because it cleans the flow of outside air that enters the vehicle through the air vents." Data collected at the end of 2003 shows that 40-plus million vehicles on the road were equipped with cabin air filtration systems.

The Car Care Council Women’s Board, a non-profit organization dedicated to promoting public awareness of vehicle maintenance, recently recognized Bosch for its cabin filter promotional and motorist education program. The program includes, among other items, a 24- x 36-inch poster and a brochure to help educate drivers about the necessity for changing their vehicle’s cabin filter periodically. The brochures are available for motorist education at many automotive retailers or repair shops.

According to Backode, "Cabin filters are especially designed to trap airborne contaminants such as dust, grime, pollen, spores, and other irritants, preventing them from entering the vehicle’s interior, keeping passengers and downstream HVAC components protected. They work much like the filter used with your heating and/or air conditioning system in your home."

To keep your vehicle’s cabin filters in optimal condition, Bosch recommends changing them once every 12,000 to 15,000 miles.

Premium Cabin Filters made by Bosch can trap close to 100% of all airborne contaminants, including pollen, dust particles, harmful substances and odors that can enter through the vehicle’s air conditioning or heating system, Backode said. "This results in marked improvement in the air inside the passenger cabin. In fact, our cabin filter ‘message’ calls particular attention to the critical role they play in helping keep vehicle interiors clean and motorists enjoy driving in an environmentally safer vehicle."

Bosch Particulate Cabin Filters feature a multi-layer design with three layers of superior mold-resistant filtration media, more pleats that provide greater surface area for higher filtration capacity, foam perimeter gaskets and an injection-molded frame when specified by original equipment. The Activated Charcoal Cabin Filters have all of the same characteristics as Particulate Filters, but go a step further. Their additional layer of activated charcoal absorbs close to 100% of toxic and foul-smelling gases such as ozone, nitrogen oxide, sulfur dioxide and hydrocarbons. An additional cover layer makes for extra protection.

Bosch suggests that when removing or replacing cabin filters, all debris that might have collected in or around the cabin filter housing also be removed to ensure a tight seal for maximum filtration.

Cabin filters, also referred to as a pollen filter, interior air filter, breather filter, micro filter, micron air filter, air-conditioning filter, passenger compartment air filter, interior ventilation filter or dust filter, are generally found under the hood, inside the glove box or under the dashboard. For more information, visit: www.boschusa.com/AutoParts/Filters/.