Nations around the world have implemented various policies to control and manage air quality but VOCs (volatile organic compounds) aldehydes, and micro hazardous air pollutants are not subject to strict regulation compared to other exhaust emission sources of passenger cars. In this regarde, this study was conducted to evaluate how hazardous pollutants from passenger cars contribute to air pollution using gasoline and LPG fuels. For the study, a passenger car with GDI(Gasoline Direct Injection) and one with the LPI(LPG Port Injection) system were selected to evaluate the contribution rate of hazardous pollutants. Catalyst temperatures were measured for the prevention of emission variation in the process of stabilizing the catalyst and the modal data from the test mode was validated by using a chassis dynamometer (Horiba). In addition, the EEPS(Engine Exhaust Particulate Sizer) and CPC(Condensation Particulate Counter) were used for the measurement of distribution and the number of particulate matters. For the analysis of micro hazardous air pollutant samples, the EPA(Environmental Protection Agency) provision governing shall test was applied.