Recently, various CO2 sensors reported in the literature may be classified in two major categories depending on measuring principle of sensors. First, the chemical CO2 gas sensors have the principal advantage of a very low energy consumption and small size. On the negative side, It is difficult to apply to a variety of practical fields because they have a short lifetime and as well as low durability. Second, NDIR-based CO2 sensor is commonly used in monitoring indoor air quality due to relatively high accuracy compared with that of a chemical CO2 gas sensor. In this paper, therefore, we evaluate NDIR-based CO2 sensors to verify applicable potentialities of them in a remote air quality monitoring system. In addition, the principle and structure of NDIR CO2 sensor is discussed, and then we analyze the CO2 concentration has been measured in the real platform of subway station for a month. Finally this paper proposes that the accuracy of the measuring values from NDIR CO2 sensor is enough for indoor air quality monitoring applications.