Cabin Air Filters (Pollen Filters). Most late-model European vehicles come standard with a cabin air filter. The purpose of these filters is to filter allergens, irritants, and airborne particles. These can include bacteria, pollution, dust, odors, and spores. The main benefit of these filters is passenger comfort, although failure to replace them at the required 15,000-mile interval could impact the efficiency of the air conditioning and heating system. In addition, no filter clogged or missing filters may cause the premature corrosion of the A/C evaporator. Another symptom that your filter may need to be replaced is the potential excess hazing of the windows. These filters are available and we recommend replacement every 15,000 miles. In heading into the summer season there are more of these particles in the air and keeping your A/C system in peak performance may require the replacement of these filters.