Comparison of the service life of an automotive cabin air filter under dust loading conditions of the laboratory environment and on-road driving

Abstract

Automobile cabin air filters (ACAFs) play an important role in protecting passengers from health risks associated with exposure to high concentrations of particulate matter (PM). Therefore, understanding the filtration mechanism of ACAFs is essential to assessing human exposure to PM. Despite the importance of ACAFs, changes in filter performance over their operation time remain largely uncharacterized; therefore, prediction of the service life of air filters is unreliable. In this study, changes in the performance of ACAFs were analyzed according to operating time under laboratory and on-road driving dust loading conditions. In the laboratory, with constant temperature and humidity, the filtration efficiency increased from 87.5% to 99.1% with increased loading time in the particle size range of 0.3–0.5 μm. This increase occurs as air paths narrow due to the clogging caused by dust, which increases filtration efficiency and causes a pressure drop. However, under on-road driving conditions, filter performance dropped to 58.7% with similar dust loading. These results indicate that dust loading, which is the most widely used variable in service life estimation, is not sufficient to characterize the service life of an ACAF. Therefore, additional studies are needed to evaluate and establish certification parameters and test methods for determining the service life of an ACAF. The present study provides useful baseline information on the lifespan of ACAFs, which will help to improve automotive cabin indoor air quality.