Measurement and influencing factors of key parameters of SVOC emission from materials

Semi-volatile organic compounds (SVOC) are widely used in indoor and in-vehicle materials, the emission characteristics of SVOC from materials can be featured by two key parameters: the gas phase SVOC concentration adjacent to the material surface (y0), and the convective mass transfer coefficient across the material surface (hm). Accurate measurement of y0 and hm is a basis for exploring SVOC emission law and assessing human health risks. Proposes a varied ventilation rate (VVR) method to determine y0 and hm quickly. Establishes a theoretical relationship between the steady state SVOC concentration (y) and ventilation rate (Q), and then the y0 and hm could be measured by performing linear fitting to the experimental data with the derived correlation. Measures the key parameters of di(2-ethylhexyl) phthalate (DEHP) from two typical in-vehicle materials with experiment, and the results demonstrate the relatively high precision of VVR method. Studies the influence of temperature (T) on the key parameters, and the results show that both y0 and hm increase with the increase of temperature, especially y0 with significant growth rate. In addition, deduces a theoretical correlation between y0 and T, which indicates that the logarithm of y0T is in a linear relationship with the reciprocal of T.