Phthalates are widely used as additives to consumer products. Many diseases have been shown to be related to the uptake of phthalates. To achieve equilibrium constant phthalate generation for mass transfer and exposure experiments, the present study developed a porous media based method using Teflon generators connected to the media with stainless steel connectors. Carbon sponges with the porosities of 20 ppi (pores per inch), 30 ppi, 40 ppi and honeycomb ceramics of 14 ppi were used as porous media fillers to evaluate the effect of temperature-controlled states, materials, and pore sizes on the generating performance of phthalates. The results showed that 30 ppi carbon sponge fillers at 25.0 ± 0.4 °C performed satisfactorily. DMP, DiBP and DEHP were used as examined phthalates and were generated at 12,800 ± 740 μg/m3, 330 ± 13 μg/m3 and 2.37 ± 0.15 μg/m3, respectively. The times to reach stable concentrations were 4.5 h, 18.5 h and 89.5 h, respectively. The reproducibility of DiBP and DEHP delivery deviated by less than 2.4%. Long-term generating experiments should be performed in the future. The porous media based method could stably deliver gaseous PAEs and tends to be widely used in the research of the adsorption of PAEs on surfaces (airborne particles, settled dust and indoor surfaces) and exposure experiments.
Keywords: Constant generating concentrations; Indoor air quality; Mass transfer; Phthalates; Porous media.
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