Search

Emissions of formaldehyde and volatile organic compounds (VOCs) from building materials may result in poor indoor air quality. The emission process can be divided into three stages over time: early, transition, and equilibrium stages. In existing studies, mass transfer models without distinguishing the early and transition stages have been widely used for characterizing the formaldehyde/VOC emissions, with three key parameters involved in these models. Many methods have been proposed for determining these parameters by fitting the corresponding models to experimental data. However, multiple groups of best-fit parameters might coexist if experimental data are obtained at the early stage (to shorten the experimental time). Therefore, we developed a novel mass transfer model to describe the early-stage emissions by assuming the building material as semi-infinite medium. The novel model indicated that the early-stage emission was governed by only two parameters, instead of three parameters, which explained the reason for the multi-solution problem of existing methods. Subsequently, the application condition of the early-stage model was clarified, showing that the early stage was very common in the emissions of formaldehyde/VOCs. Finally, a novel approach for characterizing the emissions of formaldehyde/VOCs from building materials was proposed to eliminate the negative effects of the multi-solution problem.

Clothes play an important role in dermal exposure to indoor semivolatile organic compounds (SVOCs). The diffusion coefficient of SVOCs in clothing material (Dm) is essential for estimating SVOC sorption by clothing material and subsequent dermal exposure to SVOCs. However, few studies have reported the measured Dm for clothing materials. In this paper, we present the solid-phase microextraction (SPME) based Ca-history method. To the best of our knowledge, this is the first try to measure Dm with known relative standard deviation (RSD). A thin sealed chamber is formed by a circular ring and two pieces of flat SVOC source materials that are tightly covered by the targeted clothing materials. Dm is obtained by applying an SVOC mass transfer model in the chamber to the history of gas-phase SVOC concentrations (Ca) in the chamber measured by SPME. Dm’s of three SVOCs, di-iso-butyl phthalate (DiBP), di-n-butyl phthalate (DnBP), and tris(1-chloro-2-propyl) phosphate (TCPP), in a cotton T-shirt can be obtained wi...