EVAPORATIVE LOSSES FROM SEMI-VOLATILE MIST SAMPLES

半挥发性雾样样品的蒸发损失

• 批准号: 6446083
• 负责人: Peter C. Raynor
• 金额: $ 5.39万
• 依托单位: UNIVERSITY OF MINNESOTA
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-05-01 至 2003-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6446083
• 关键词: air pollution; air sampling /monitoring; environmental contamination; environmental exposure; evaporation; metals; occupational health /safety

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.

理论、实验和现场测量表明，金属加工液雾化 在被过滤器收集后，可以蒸发到通过的空气中。 这些蒸发损失将导致浓度的负偏差 测量. 这些损失的程度尚未得到充分说明。 虽然偏差的程度取决于许多因素，如流体成分， 环境温度，并在采样前稀释雾，蒸发是 当取样空气的汽相不饱和时， 这些化合物聚集在过滤器上。 拟议的研究将 系统地评估喷雾取样过程中的蒸发损失， 涉及校正浓度测量偏差的方法。 因此 在该项目中，工人暴露于金属加工液气溶胶将被 评估更准确。 本文的工作主要分为三个部分：（1）从理论上研究蒸发过程 立场观点 利用现有的数值模型和即将开发的新模型， 评价了影响样品蒸发的因素的重要性， 过滤器中的金属加工液;（B）在实验室中研究蒸发 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; 在野外研究蒸发。 在大型和小型设施中，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 蒸发发生在真实的设施中。 如果可以预测现场的蒸发损失，研究人员将能够 重新评估历史雾浓度数据，以确定蒸发 在过去一直是个问题 重新评估的数据可能会被更多地使用 有效地在流行病学研究的健康影响的金属加工 流动的薄雾