Predicting Evaporation Rates from Pools

Abstract

A number of simplified approaches, based on semi-empirical models and algebraic formulas, often derived from the correlation of experimental data, are available to predict the evaporation rate of chemicals from pools. In this work they are compared, based on their performances in estimating the evaporation rates determined in some sets of experiments reported in the literature, involving different chemicals, pool geometries, wind velocities, etc. Generally, the models predict correctly the data used in the fitting to determine their own parameters, but most of them fail when applied to other data sets. No model appear capable of predicting all the available sets of literature data with errors within ± 30%: nevertheless, some models application guidelines can be derived. In particular, the model of Heymes et al. (2013), provides reasonable estimates of the evaporation rates of a variety of compounds in rather different operating conditions, for wind speed exceeding 1 m/s, while the simple model of Mackay and Wesembeeck (2014) should be preferred in the absence of ventilation. Other models, such as those of Hummel et al. (1996), Stiver and Mackay (1996) and EPA (1999) can be applied within proper intervals of wind speed, molecular weight and vapour pressure of the chemical.