Multiscale analysis of material flow and computational fluid dynamics for predicting individual diethyl-hexyl phthalate exposure concentration in indoors

Abstract

The establishment of a healthy indoor environment requires the accurate evaluation of an individual’s exposure to pollutants. The concentration of indoor chemical pollutants is a representative indicator for such evaluation and is generally measured on-site. Moreover, material flow analysis (MFA), using macroscopic statistical data, is a reasonable method for objectively evaluating pollution on a wide scale; however, no effective strategy exists for the prediction of indoor air pollution, nor for the assessment of an individual’s exposure from social stock data. Accordingly, we developed a novel integration method comprising MFA and computational fluid dynamics (CFD) with a computer-simulated person (CSP) to establish a framework for evaluating indoor pollutant concentration and individual exposure of residents. We focused on diethyl-hexyl phthalate (DEHP) and first estimated the amount of DEHP-containing product accumulation in Japan by MFA. Second, we conducted a thorough survey and measurement of DEHP emission rates. Using these results as boundary conditions for indoor CFD with CSP, the individual exposure of a resident, in a standard residential house, was quantitatively evaluated. The total daily exposure per unit of body weight was estimated to be more than 100 (μg/kg/d) in the worst-case scenario which was considered the upper limit for exposure in this analysis.