Predicting emissions of volatile and semivolatile organic compounds from building materials: A review

Volatile organic compounds (VOCs) and semivolatile organic compounds (SVOCs) constitute important classes of indoor air contaminants and characterizing their emissions from building materials and consumer products is of interest for risk assessment and the development of environmentally benign products. Compared with emission chamber studies, emission models provide a more cost effective and powerful way to examine the emission behavior of VOCs and SVOCs. The objective of this paper is to review existing mechanistic models for predicting VOC and SVOC emissions from various sources, investigate their differences and similarities, and discuss the mass-transfer mechanisms on which the models are constructed. Because the usefulness of the emission models largely depends on the availability and reliability of model parameters, techniques for estimating key model parameters are also reviewed. The models covered in this review fall into three categories: models for VOC emissions from solid materials; models for VOC emissions from liquid materials; and models for SVOC emissions. VOC and SVOC emissions can be modeled within a consistent mass-transfer framework with the three model categories being intimately related. While substantial advances have been made in developing predictive models and understanding emission mechanisms, large knowledge gaps exist and further research is needed.