EVAPORATIVE LOSSES FROM SEMI-VOLATILE MIST SAMPLES

理论、实验和现场测量表明，金属加工液雾化 它们被过滤器收集后，可以蒸发成经过的空气。 这些蒸发损失将导致浓度的负面偏向。 测量。这些损失的程度还没有完全被描绘出来。 尽管偏置程度取决于许多因素，例如流体组成， 环境温度和采样前雾气的稀释，蒸发量 很可能在采样空气的气相未饱和时发生 使化合物积累在过滤器上。拟议的研究将 系统地评估雾气采样期间的蒸发损失，并将导致 涉及在浓度测量中校正偏差的方法。结果 在该项目中，工人暴露在金属加工液气雾剂中的时间将是 评估更准确。 建议的工作包括三个部分：(A)从理论上研究蒸发 立场。利用现有的和将要开发的新的数值模型， 对影响样品蒸发因素重要性的评价 来自过滤器的金属加工液；(B)在实验室研究蒸发 实验。根据建模结果，选择测试条件 在实验室中验证这些条件的重要性 蒸发损失。这些实验将验证数值模拟的有效性； 研究田间蒸发情况。在大大小小的设施中，确定 在各种条件下的蒸发损失。有了结果，我们将 确定如何使用模型来准确预测 在真实设施中发生的蒸发。 如果能够预测田间蒸发损失，研究人员将能够 重新评估历史上的雾浓度数据以确定蒸发是否 在过去一直是个问题。重新评估的数据可能能够使用更多 有效开展金属加工对健康影响的流行病学研究 雾气弥漫。

Theory, experiments, and field measurements show that metalworking fluid mists can evaporate into passing air after they have been collected by filters. These evaporative losses will lead to negative biases in concentration measurements. The extent of these losses has not been delineated fully. Although the degree of bias depends on many factors such as fluid composition, ambient temperature, and dilution of mist prior to sampling, evaporation is likely to occur whenever the vapor phase of the sampled air is not saturated with the compounds accumulated on the filter. The proposed research will evaluate evaporative losses during mist sampling systematically and will lead to methods to correct for biases in concentration measurements. As a result of the project, worker exposures to metalworking fluid aerosols will be assessed more accurately. The proposed work has three parts: (a) study evaporation from a theoretical standpoint. Using existing numerical models and new ones to be developed, evaluated the importance of the factors affecting evaporation of sampled metalworking fluids from filters; (b) study evaporation in laboratory experiments. Based on results from the modeling, select conditions for tests in the laboratory to verify the importance of these conditions upon evaporative losses. These experiments will validate the numerical modeling; study evaporation in the field. In large and small facilities, determine evaporative losses over a wide range of conditions. With the results, we will determine how the models can be used to predict accurately the amount of evaporation occurring in real facilities. If evaporative losses in the field can be predicted, researchers will be able to reevaluate historical mist concentration data to determine if evaporation has been a problem in the past. Reevaluated data may be able to be used more effectively in epidemiological studies on the health effects of metalworking fluid mists.