Study on the mechanism of SVOC adsorption onto airborne particles in indoor air

Abstract

Abstract Semi‐volatile organic compounds (SVOC), such as di‐2‐ethylhexyl phthalate (DEHP), not only cause chemical sensitivity but can also trigger asthma. SVOCs are adsorbed onto airborne particles as well as gas‐phase molecules in indoor air, owing to their low vapor pressure. Therefore, 3 models are suggested to evaluate partitioning between the gaseous and particulate phases using data from previous studies. In this study, the characteristics of each model were extracted, and the mechanisms of DEHP adsorption onto test airborne particles were investigated under controlled temperature, airborne test particle concentration, and air exchange rate conditions in a chamber. The total DEHP concentration increased from 1.6 to 25.6 μg/m3 as the chamber temperature increased from 15 to 35°C. However, the particulate DEHP ratio φ decreased with the increase in temperature. The high airborne particle concentration caused an increase in the particulate DEHP concentration. Moreover, the estimates based on the Junge model corresponded well with the results of these experiments, whereas the Mackay and Pankow models overestimated the values of φ compared to the results of these experiments. These results indicate that particulate surface concentration is related to the DEHP adsorption mechanism onto airborne particles.

Keywords

• adsorption
• fine particle
• indoor environment
• semi‐volatile organic compounds