BAuA: Federal Institute for Occupational Safety and Health, Unit "Exposure Scenarios", Friedrich-Henkel-Weg 1-25, 44149 Dortmund, Germany.
Int J Environ Res Public Health. 2022 Feb 10;19(4):1957. doi: 10.3390/ijerph19041957.
In many professional and industrial settings, liquid multicomponent mixtures are used as solvents, additives, coatings, biocidal products, etc. Since, in all of these examples, hazardous liquids can evaporate in the form of vapours, for risk assessments it is important to know the amount of chemicals in the surrounding air. Although several models are available in legal contexts, the current implementations seem to be unable to correctly simulate concentration changes that actually occur in volatile mixtures and in particular in thin films. In this research, the estimation of evaporation rates is based on models that take into account non-ideal behaviour of components in liquids and backpressure effects as well. The corresponding system of differential equations is solved numerically using an extended Euler algorithm that is based on a discretisation of time and space. Regarding air dispersion of volatile components, the model builds upon one-box and two-box mass balance models, because there is some evidence that these models, when selected and applied appropriately, can predict occupational exposures with sufficient precision. That way, numerical solutions for a wide variety of exposure scenarios with instantaneous and continuous/intermittent application, even considering "moving worker situations", can be obtained. A number of example calculations have been carried out on scenarios where binary aqueous solutions of hydrogen peroxide or glutaraldehyde are applied as a biocidal product to surfaces by wiping. The results reveal that backpressure effects caused by large emission sources as well as deviations from liquid-phase ideality can influence the shape of the concentration time curves significantly. The results also provide some evidence that near-/far-field models should be used to avoid underestimation of exposure in large rooms when small/medium areas are applied. However, the near-field/far-field model should not be used to estimate peak exposure assuming instantaneous application, because then the models tend to overestimate peak exposure significantly. Although the example calculations are restricted to aqueous binary mixtures, the proposed approach is general and can be used for arbitrary liquid multicomponent mixtures, as long as backpressure effects and liquid-phase non-idealities are addressed adequately.
在许多专业和工业环境中，液体多组分混合物被用作溶剂、添加剂、涂料、杀生剂等。由于在所有这些例子中，危险液体都可能以蒸气的形式蒸发，因此，为了进行风险评估，了解周围空气中的化学物质含量非常重要。尽管在法律环境中有几种模型可用，但当前的实现似乎无法正确模拟挥发性混合物中实际发生的浓度变化，尤其是在薄膜中。在这项研究中，蒸发速率的估计基于考虑液体中各成分非理想行为和背压效应的模型。相应的微分方程组通过基于时间和空间离散化的扩展 Euler 算法进行数值求解。关于挥发性成分的空气扩散，该模型基于一盒子和两盒子质量平衡模型，因为有一些证据表明，这些模型在适当选择和应用时，可以足够精确地预测职业暴露。这样，就可以针对瞬时和连续/间歇应用的各种暴露场景获得数值解，甚至可以考虑“移动工人情况”。已经对一些示例计算进行了过氧化氢或戊二醛的二元水溶液作为杀生剂通过擦拭施用于表面的情况进行了计算。结果表明，大排放源引起的背压效应以及偏离液相理想状态都可能显著影响浓度时间曲线的形状。结果还提供了一些证据，表明在应用小/中面积时，为了避免在大房间中低估暴露，应该使用近场/远场模型。然而，不应使用近场/远场模型来估计瞬时应用时的峰值暴露，因为模型会显著高估峰值暴露。尽管示例计算仅限于水溶液二元混合物，但所提出的方法是通用的，可以用于任意液体多组分混合物，只要充分考虑背压效应和液相非理想性。
