Abstract
Phthalic acid esters (PAE) are typical substances of semi-volatile organic compounds (SVOC) and are widely used as plasticizers. This study performed fundamental examination on gas-particulate phase percentage in indoor air of three PAEs, namely DBP, DEP and DEHP by employing a glass fiber filter and two C18 porous polyflon filters in a room that wallpaper was used. The mean concentrations of PAE were the order of 1 μg/m3. DEP of small molecular weight was almost gas-phase and more than 60% of DEHP of large molecular weight was particle-phase. On the other hand the greater part of DBP of middle molecular weight was gas-phase, however, when the room temperature was low, the percentage of particulate phase tended to increase.
Authors have made a passive sampler for SVOC, which is large in a sampling rate due to a windbreaker and diffusion-membrane-less sampling face. Parallel measurement with both active and passive sampling was applied to obtain the sampling rates of DEP, DBP and DEHP. In addition, the measured sampling rate was compared with theoretical sampling rate, which was calculated with a sampler dimension and diffusion coefficients. The sampling rates of gas-phase DEP and DBP were almost consistent with the theoretical sampling rates. However, further investigations should be required on the practical application of this passive sampler, because the influence of airflow was significantly found on the sampling rates.
