Exponential Decay Model of TVOC Emission from Indoor Building Materials

Abstract

Total volatile organic compounds (TVOC) are mainly derived from indoor building materials and are one of the main causes of indoor air pollution. This paper presents a research on simulating the TVOC release of building materials in the environmental chamber. In this work, a simple and practical prediction model of exponential decay is established to study the transport and the emission behaviors under the effect of convective mass transfer theory. Based on this theory, the model considers the porous structure of indoor building materials and assumes that concentration of TVOC at the boundary of building material obeys exponential distribution. This paper focuses on two kinds of indoor building materials, interior wall coatings and wood coatings. Numerical simulation and experimental parameters are obtained by environmental chamber method. By modelling the emission of TVOCs, and comparing the present model with the classical model, the validity of the present model can be confirmed. Besides, from the results of the fitting, it can be seen that the new exponential decay predition model has a better agreement with the experimental data, and which can describe the release characteristics and transmissionmechanisms of TVOCs more accurately, and the root mean square error is much less than the classical model.

The Ability to Control VOC Emissions from Multilayer Building Materials

“…where EF is emission factor mg m −2 h −1 ; A is floor surface m 2 ; V-is chamber volume m 3 ; N is air change rate h −1 , C out is outdoor VOC concentration mg m −3 and C is chamber VOC concentration mg m −3 ; t-time h. Two recently published analytical models of emissions were developed in 2020 by two Chinese scientists' teams with a very similar composition Zhang, Niu, Liu et al [42] and Zhang, Liu, Wu et al [43]. These are exponential mass transfer models that eliminate some of the disadvantages of the empirical model, and their parameters have a justified reference to the parameters of physical models.…”

“…where K ma is an interface partition coefficient of TVOC between the material and the interface, h is the convective mass transfer coefficient m h −1 and B is constant. The authors of the model Zhang, Niu, Liu et al [42] ignored the process of filling the environmental chamber with TVOC without chemical reactions, Equation (13), which allowed to simplify to the following exponential decay model:…”