In air pollutant monitoring using sensors, moisture can adversely affect the analytical accuracy of volatile organic compounds (VOCs). Therefore, a new moisture pretreatment device (KPASS–Odor) for analyzing VOCs in the air was developed, based on frost and created by a desublimation process inside a cold tube. The performance of KPASS–Odor was compared with conventional devices (i.e., a Nafion^TM dryer and a cooler) through the measurements of low water-soluble VOCs (i.e., benzene, toluene, ethyl benzene, p-xylene, and styrene) and relatively high ones (i.e., methyl-ethyl ketone, methyl isobutyl ketone, butyl acetate, and isobutyl alcohol) using gas chromatography (GC) and sensor methods. Regarding the GC method, the recovery rates for KPASS–Odor and the cooler were >95% and >80%, respectively, at a flow rate of 500 mL/min for all compounds. For the Nafion^TM dryer, the recovery rates differed between low and high water-soluble compounds, which exhibited the rates ≥88% and ≤86%, respectively. In terms of the sensor method, the VOC recovery rates of KPASS–Odor and the Nafion^TM dryer were found to be >90% and <50%, respectively. Therefore, KPASS–Odor was determined to be the most suitable moisture pretreatment device for highly soluble VOCs of concern in this study.

In this study, the effects of various moisture pretreatment devices (MPDs) on the analytical process of trichloroethylene (TCE) and nitrous oxide (N₂O), which are representative organic and inorganic compounds emitted from semiconductor industries, were investigated. Three types of MPDs—a KPASS (MPD_K), a Nafion™ dryer (MPD_N), and a cooler (MPD_C)—were evaluated for their performance under sample gas conditions of 25 °C and 150 °C at various flow rates. MPD modification was also carried out to improve their performance at high loading capacities. The results indicated that humidity introduced significant bias in the measurement of TCE and N₂O according to the analyzers explored in this study. At a flow rate of 1 L/min, among the MPDs, MPD_N exhibited the highest moisture removal efficiency, followed by MPD_K and MPD_C. In terms of analyte recovery rates, MPD_K achieved the highest TCE recovery, followed by MPD_N and MPD_C, across all tested conditions. Conversely, MPD_C resulted in the lowest N₂O recovery rates, whereas MPD_K and MPD_N maintained over 95% recovery rates. At a flow rate of 4 L/min, MPD_N and MPD_C did not work at high temperatures. In contrast, the modified MPD_K, which received less investment compared to many other membranes, showed an acceptable moisture removal efficiency (>85%) and analyte recovery (>98%). Therefore, modified KPASS is recommended as a useful moisture pretreatment device for the analytical process of TCE and N₂O at both normal and high loading capacities.