Present situation of mathematical models predicting the indoor environment levels of vapor and gas of chemicals used at the workplace

摘要

Exposure assessment is essential in evaluating health risks of workers exposed to chemicals at the workplace. Mathematical models predicting indoor environment levels have recently been in use as one of practical exposure assessment methods. The reviewed models predicting indoor environment levels in various workplace situations were divided into two groups in view of clarity and usability at the workplace. One of the two groups comprised generation models that prescribed the way of evaporation or emission from the sources into the workplace air. And the other included dispersion models that prescribed the way of dispersion through mixing, diffusion, and advection at the workplace. Six generation models were considered particularly relevant: they included a saturation vapor model, a material balance model, a liquid pool model, a backpressure-affected model, a small liquid spill model and a pulse release model. As dispersion models, five models were referred to, including a well-mixed room model, a near field/far field model, a multi-zone model, a turbulent eddy diffusion model and another turbulent eddy diffusion model involving advection. In predicting indoor environment levels, a combination of a generation model and a dispersion model was found generally practical.