Research On VOCs Emission Reference Samples For Environmental Chambers: Design Principle And Application

Indoor building materials and furniture are the main sources for indoor Volatileorganic compounds (VOCs) emissions, resulting in potential health risks.Environmental chamber systems are commonly used to measure the emission rates andthe emission key characteristic parameters of VOCs emissions. Accurate measurementsof the emission rates and the emission key characteristic parameters of VOCs are thebases for the more in-depth studies, such as VOCs emission mechanism, humanexposures, and VOCs engineering control. However, there is lack of effective method toevaluate the measurement accuracies of using environmental systems to measure theemission rates and the emission key characteristic parameters of VOCs. To solve thisproblem, researches on VOCs emission reference samples for environmental chambersare carried out and presented in this paper. The main academic contributions are asfollows:(1) A liquid-inner tube diffusion-film-emission (LIFE) emission reference sampleis designed. The VOCs emission rate of the LIFE reference is controllable andadjustable. To make the VOCs emission rate of the LIFE reference similar to buildingmaterials, a general design method and a dimentionless emission model for the LIFEreference are developed. The protocols for choosing appropriate diffusion films for theVOCs emission reference samples are established. This design method is applicable tothe VOCs such as toluene that has analytical reagent or formaldehyde that doesn’t haveanalytical reagent under normal temperature and pressure.(2) To make the emission key characteristic parameters of the LIFE referencesimilar to building materials, a method to design the diffusion coefficient, partitioncoefficient, and the initial emittable VOCs concentration of the LIFE reference isdeveloped.(3) Inter-laboratory comparisons of full-scale environmental chambers are carriedout using the toluene LIFE emission reference samples to determine the inter-laboratorycoefficient of variation. Temperature variations in the environmental chambers and theuncertainties in the chemical analysis are the main reasons for the uncertainties inmeasuring the VOCs emission rates in environmental chamber systems.