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An Experimental Study for Examining the Effects of Environmental Conditions on Diffusion Coefficient of VOCs in Building Materials
Author(s) -
Farajollahi Yashar,
Chen Zhi,
Haghighat Fariborz
Publication year - 2009
Publication title -
clean – soil, air, water
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.444
H-Index - 66
eISSN - 1863-0669
pISSN - 1863-0650
DOI - 10.1002/clen.200900053
Subject(s) - thermal diffusivity , boiling point , humidity , relative humidity , diffusion , octane , chemistry , environmental chemistry , vapor pressure , hexane , volatile organic compound , analytical chemistry (journal) , thermodynamics , chromatography , organic chemistry , physics
The diffusion coefficients (diffusivity) of five different volatile organic carbon compounds (VOCs), i. e., octane, isopropanol, cyclohexane, ethyl acetate, and hexane, were experimentally determined for a building ceiling tile. The effects of typical indoor environmental conditions on the diffusivity of the VOCs in the tile were evaluated over a range of temperatures (15, 23, 31 and 39°C) and at three relative humidity percentages (0, 20, and 40%). Three novel methods were developed during the course of this study: (i) a two‐chamber experimental apparatus for diffusivity testing of building materials, (ii) a GC/MS method for determining the above VOCs, and (iii) a two‐factor method for analyzing the statistical significance effects of temperature and humidity on VOC diffusivity. The results showed that the diffusion coefficients of the VOCs were positively related to their vapor pressure, but not to their boiling point, molecular weight or polarity index. No difference was observed between the diffusion coefficient of a VOC present alone or as part of a mixture of VOCs. Temperature and humidity (in the range of a typical indoor environment) had minor significant effects on the diffusion coefficient, with temperature being more important than humidity. It is hypothesized that water vapor molecules may occupy the pores of the ceiling tile material under conditions of high relative humidity and prevent the VOC molecules from diffusing through the pores.