This study conducted comparison and data analysis of evaluation results from three kinds of monitoring methods for indoor air quality monitoring, which are Korean Official test method for indoor air quality, monitoring method by gas analyzer, and continuous measurement by using sensor. NO₂, one of indoor air pollutants, was selected as a evaluation factor for this study because it is commonly generated during the operation of potable gas range. Monitoring results of NO₂ concentration from three subjected methods show that background concentration of NO₂, before operation of portable gas range, was 43.05~50.22ppb. On the other hand, NO₂ concentration for four and half hours (4½) after gas range operation was 64.31~69.89ppb in average. Average concentration of NO₂ during first thirty (30) minutes was increased about 33.85~49.39% than the concentration of NO₂ before operation of gas range. </br>In general, monitoring results by utilizing NO₂ gas analyzer was 8.1% higher than the results by continuous measurement using sensor method. In case of monitoring method using sensor, the results was lower about 6.1% than Korean official test method, and lower about 11.7~3.2% than NO₂ gas analyzer. Especially, change rate of concentration for first thirty (30) minutes measured by Korean official test method was 50ppb/hr, which is 44.4% lower than the change rate from NO₂ gas analyzer, 90ppb/hr, and 43.2% lower than results from sensor, 88ppb/hr. </br>In accordance with this study, it is concluded that monitoring frequency for indoor air quality management must be shorten during the time period having significant change rate of NO₂ concentration. In other words, air quality monitoring must be considered characteristics of concentration changes as well as accuracy of measurement.

In this study, amenity evaluation technique for indoor air quality in the underground space was developed and evaluated real-time amenity by utilizing real-time sensor monitoring system equipped with the technique. The factors used for amenity evaluation were PMV value, VOCs, illumination, PM₁₀ and CO₂. The amenity value with 60 percent represents the environmental standards of subjected factors. Based on the field survey using the monitoring system developed under this study, the amenity values of CO₂ whose environmental standard is 1,000ppm were 97% for 400ppm and 26% for 1,100ppm, respectively. That of PM₁₀ having 150㎍/㎥ as an environmental standard were 99% for 25㎍/㎥ and 80% for 100㎍/㎥. Evaluated amenity based on VOCs concentration at the subjected areas was in bad condition. And those for PM10 and CO₂ were dependant on the floating population. From the results of this study, the real-time sensor monitoring system installed with the amenity evaluation technique could be a practical tool to evaluate indoor air quality to manage air quality of underground spaces like subway station. New amenity assessment technique using a real-time sensor monitoring of indoor air quality as well as physical environmental properties was developed in this study. The concentrations of CO₂, PM₁₀, VOCs were considered as new parameters to analyze the indoor air quality and they are included in an amenity assessment program of indoor area. We found that the new method is better to express the amenity degree of residents through field tests than conventional thermal comfort technique.