Emissions of Phthalates from Indoor Flat Materials in Chinese Residences

Phthalates are ubiquitous pollutants in residential environments. Indoor airborne phthalate concentrations in Chinese residences are comparable to, or even higher than, those of western countries. However, the major sources of phthalates in Chinese residences are not well-known. In this study, we measured the phthalates emission features of 23 flat materials used in Chinese residences in the laboratory environment, including the mass fraction (wt) and the concentration in the air adjacent to the material surface ( y₀). The measured wt of seven phthalates ranged from below the limit of quantitation (LOQ) to 17%, and y₀ ranged from LOQ to 2 μg/m³. To evaluate the potential contributions of the studied materials to phthalates in residential air, concentrations of di-2-ethylhexyl phthalate (DEHP, a typical indoor phthalate) in air due to the emissions from selected materials in typical Chinese residential scenarios were modeled and compared with measured concentrations from the literature. The modeled gas-phase, particle-phase, and airborne concentrations of DEHP in residential air due to emissions from the selected materials were 2-65 times lower than the mean values of measured concentrations. To formulate appropriate control strategies, further efforts are needed to identify the dominant sources of phthalates in Chinese residences.