The primary goals of vehicle cabin air filtration are to improve air quality in the passenger compartment, protect the HVAC components from contaminants, and to increase car interior cleanliness. In order to accomplish these goals, cabin air filters must have suitable performance characteristics, including filtration efficiency and pressure drop.Filter performance was measured after operation in two geographical regions. The field test results show that after approximately 24,000 km, filters tested in Arizona trapped over three times more particulate matter than filters tested in Alabama. The pressure drop and efficiency results from filters loaded in a laboratory with various test dusts were compared to the results from the field loaded filters. The comparison showed that filters loaded with SAE Fine dust best reflect the actual pressure drop with both the Alabama and Arizona field tested filters.