~) Pergamon Chemosphere, Vol.39, No. 14,pp. 2535-2547,1999 © 1999 Elsevier Science Ltd.Allrights reserved 0045-6535/99/$- seefront matter PII: S0045-6535(99)00156-3 CHEMICAL COMPOSITION ANALYSIS AND ITS APPLICATION IN ESTIMATION OF VOC EMISSION RATES FROM HYDROCARBON SOLVENT-BASED INDOOR MATERIALS Jiping Zhu*, Jianshun Zhang and Chia-Yu Shaw Institute for Research in Construction, National Research Council Canada, Building M-24, Montreal Road Campus, Ottawa, Ontario, Canada K1A 0R6, e-mail: jiping.zhu@nrc.ca (Received in USA 1February 1999; accepted 26April1999) ABSTRACT A method for estimating VOC emission rates from hydrocarbon solvent-based indoor materials has been developed. The estimation is based on the assumption that the emission rate of individual VOCs is proportional to its molar fraction in the evaporative mixture at the time, its saturated pure vapor pressure and total remaining VOCs in the material. The paper demonstrates, through three hydrocarbon solvent-based polyurethane surface coating materials, a practical way to calculate these three parameters using chemical composition analysis results. The estimated total VOC emission rates were in good agreement with the results of weight loss experiments. © 1999Elsevier ScienceLtd. All rightsreserved INTRODUCTION Emissions from hydrocarbon solvent-based indoor materials such as polyurethane and wood stains can be divided into at least two stages. In the first stage the emissions can be characterized in general as high but fast decaying, while in the second stage emissions are low and slowly decaying. Emissions during the first stage, especially in the initial several hours after application, are largely controlled by evaporation rates of the solvent [1,2]. Emissions can be described by both VB model [3] and VBX model [4]. Both models are based on mass transfer theory. VB model is used for describing total VOC (TVOC) 2535