Most cars built since 2001 come factory-equipped with a cabin air filter that is designed to clean and protect the air inside the vehicle. It prevents pollutants such as ozone, particulates, pollen, dirt, dust and soot -- that aggravate any respiratory condition -- from entering the car through the heating and air conditioning vents.

"Over time, however, cabin air filters can get clogged and actually multiply the dangers from these pollutants when the heating and air conditioning system blows them around inside the car with no avenue for escape," said Ramon Nunez, spokesman for Purolator Filters NA LLC. Purolator supplies high quality automotive filters to the North American aftermarket. www.purolatorautofilters.net.

Simply checking and replacing your car's cabin air filter every 12,000 to 18,000 miles is the easiest and least expensive way to ensure that you are not inhaling irritants and allergens that will compromise your driving comfort or that of your passengers.

A cabin air filter may also be called a pollen filter, air-conditioning filter, passenger compartment air filter, interior ventilation filter or dust filter.

Normally, the cabin air filter is located in the cabin air intake, under the dash or even behind the glove box. Replacing it can take anywhere from 10 minutes to an hour, depending on its location and how difficult it is for a do-it-yourselfer or a technician to reach, Nunez said.

Purolator offers its BreatheEASY replacement cabin air filters for most cars, domestic and import. Its non-woven, engineered media traps the finest particles of dust, soot and pollen, adsorbs odors and reduces dust accumulation inside the car. Visit the Purolator Web site at www.purolatorautofilters.net to see if a cabin air filter is available for a particular vehicle.

Approximately 45 million vehicles in the United States have cabin air filters, according to Nunez. Refer to your owner's manual or check with your technician to see if your vehicle has one.