Koivisto A J, Jensen A C Ø, Levin M, Kling K I, Maso M Dal, Nielsen S H, Jensen K A, Koponen I K
National Research Centre for the Working Environment, Lersø Parkallé 105, Copenhagen DK-2100, Denmark.
Environ Sci Process Impacts. 2015 Jan;17(1):62-73. doi: 10.1039/c4em00532e. Epub 2014 Nov 14.
A Near Field/Far Field (NF/FF) model is a well-accepted tool for precautionary exposure assessment but its capability to estimate particulate matter (PM) concentrations is not well studied. The main concern is related to emission source characterization which is not as well defined for PM emitters compared to e.g. for solvents. One way to characterize PM emission source strength is by using the material dustiness index which is scaled to correspond to industrial use by using modifying factors, such as handling energy factors. In this study we investigate how well the NF/FF model predicts PM concentration levels in a paint factory. PM concentration levels were measured during big bag and small bag powder pouring. Rotating drum dustiness indices were determined for the specific powders used and applied in the NF/FF model to predict mass concentrations. Modeled process specific concentration levels were adjusted to be similar to the measured concentration levels by adjusting the handling energy factor. The handling energy factors were found to vary considerably depending on the material and process even-though they have the same values as modifying factors in the exposure models. This suggests that the PM source characteristics and process-specific handling energies should be studied in more detail to improve the model-based exposure assessment.
近场/远场（NF/FF）模型是预防性暴露评估中一种被广泛接受的工具，但它估算颗粒物（PM）浓度的能力尚未得到充分研究。主要问题与排放源特征有关，与例如溶剂相比，PM排放源的特征定义不够明确。表征PM排放源强度的一种方法是使用材料扬尘指数，该指数通过使用诸如处理能量因子等修正因子进行缩放，以对应工业用途。在本研究中，我们调查了NF/FF模型预测油漆厂中PM浓度水平的准确性。在大袋和小袋粉末倾倒过程中测量了PM浓度水平。确定了所用特定粉末的转鼓扬尘指数，并将其应用于NF/FF模型以预测质量浓度。通过调整处理能量因子，将模拟的特定工艺浓度水平调整为与测量浓度水平相似。结果发现，尽管处理能量因子在暴露模型中作为修正因子具有相同的值，但它们会因材料和工艺的不同而有很大差异。这表明应更详细地研究PM源特征和特定工艺的处理能量，以改进基于模型的暴露评估。
