Abstract
Since Phthalic Acid Ester (PAE), which are representative substances of semi volatile organic compounds (SVOCs), have low vapour pressures, the possibility of being present in both the gaseous and particulate phases has been identified. In order to partition the gaseous and particulate phases of PAE in an indoor air, this study examined the applicability of the Denuder-Filter (D-F) sampling method which used VOC denuder for upstream and a quartz glass fiber filter for downstream. First, the theoretical values were determined for the penetration of the gaseous and particulate phases for a VOC denuder based on the Gormley-Kennedy Equation. Then, for verification, a method of generating exposure gas that was able to be in a stable concentration was studied. Next, experimental values were determined for the penetration of the gaseous and particulate phases to the denuder using the exposure gas and indoor suspended dust. With a flow rate of 5 L/min, most PAEs were adsorbed by the denuder, while particulate penetration ratio of particulate matter larger than 10 nm was about 88% or more. The results show that the gaseous and particulate phases could be partitioned. In addition, it was performed parallel measurement with both the Tenax sampling and the D-F sampling method for examination on gas-particulate phase partitioning fraction in indoor. The concentration became in order of DBP, DEHP, and DEP and without re-volatilization of PAE adsorbed on the denuder. PAE may have in large part of gaseous phase on more than 28°C of room temperature.
