Prediction and validation of diffusive uptake rates for indoor volatile organic compounds in axial passive samplers

Abstract

The diffusive uptake rate is essential for using passive samplers to measure indoor volatile organic compounds (VOCs). The traditional theoretical model of passive samplers requires available regression formulas of uptake rates and physicochemical properties of adsorbents to predict the uptake rate. However, it is difficult to obtain the uptake rates of different VOCs under different sampling periods, and it is also difficult to obtain the physical parameters of adsorbents accurately and effectively. This study provides a reliable numerical prediction method of diffusive uptake rates of VOCs. The modeling was based on the standard automated thermal desorption (ATD) tubes packed with Tenax TA and the mass transfer process during adsorption. The experimental determinations of toluene uptake rate are carried out to verify the prediction model. Diffusive uptake rates of typical indoor VOCs are obtained from the literature to calibrate the key apparent parameters in the model by statistical regression fitting. The predicted model can provide the VOC diffusive uptake rates under different sampling duration with an average deviation of less than 5%. This study can provide the basis for fast and accurate prediction of diffusive uptake rates for various VOC pollutants in built environments.