Skin surface boundary conditions for dermal exposure assessment using computer-simulated person

The complex interactions among airborne pollutants, airflow around the human body caused by human metabolic heat generation, and dermal exposure are poorly understood. This study conducted chamber experiments using a thermal manikin and a computational fluid dynamic (CFD)–computer-simulated person (CSP) hybrid analysis integrated with a physiologically based pharmacokinetic model to investigate how micro-climate formation around the human body impacts pollutant transport and dermal exposure. Toluene, a representative volatile organic compound, was selected as a target indoor pollutant.

Experimental and numerical results showed that metabolic heat generation altered convective airflow patterns around the human body, influencing pollutant concentration distributions and the dermal absorption rates. Without thermoregulation, the maximum dermal absorption flux increased by up to 221 % compared to the condition with metabolic heat. In contrast, buoyancy-driven airflow induced by metabolic heat generation enhanced air mixing, reducing the average dermal absorption flux by approximately 68 %. A passive flux sampler was also numerically implemented within the CFD environment to precisely replicate the experimental passive-sampling conditions and validate the reliability of the numerical model. This study established a framework for quantifying dermal exposure in indoor environments and provides insights for improving exposure risk assessment and ventilation strategies that mitigate the health risks associated with gaseous pollutants in occupational and residential settings.