The purpose of this study is to provision the standard method for ensuring the reliability of measuring indoor air quality in public transportation. The objective is to determine the difference in the measured concentration values according to various conditions. These variables include measurement conditions, measurement equipment, measurement points, and measurement time. The value differences are determined by measuring the PM10 and CO2 concentration of subways, and express buses and trains, which are targets of indoor air quality management. The concentration of CO2 was measured by the NDIR method and that of PM10 was measured by the gravimetric method and light-scattering method. Statistically, the results of the concentration comparison according to the measurement points of the public transportation modes were not significantly different (p > 0.05), and it is deemed that the concentration is not affected by the measurement points. In terms of the concentration analysis results according to the measurement method, there was a difference of the concentration between the gravimetric and light scattering method. In the case of the light scattering method, the concentration differed depending on whether it was corrected with standard particles in the laboratory environment.