Isocyanates are reactive semivolatile contaminants that must be assessed in occupational environments, and specific evaluation methods are required to address the challenges related to isocyanate emission characteristics. Several standard methods exist, but significant differences remain regarding the diversity of industrial isocyanate emissions. This study presents a method to establish a baseline comparison of three sampling principles. A fine aerosol (mass median aerodynamic diameter of 250 nm) of pure methylene diphenyl diisocyanate (MDI) was produced (5–60 μg m⁻³) using a laboratory generation system (n = 31 generation experiments). Airborne MDI was measured with the following four methods, with an emphasis on the spatial distribution of the collected MDI within the sampler: (1) Swinnex cassette 13 mm, glass fibre filter (GFF), 9-(N-methylaminomethyl) anthracene (MAMA-Swin); (2) closed-face cassette (CFC) 37 mm, GFF (end filter and inner walls), MAMA-37; (3) impinger and backup GGF, 1,2-methoxyphenylpiperazine (MP) (ISO 16702/MDHS 25); and (4) denuder and GFF (Asset EZ4-NCO), dibutylamine (DBA) (ISO 17334-1). Bland and Altman analyses determined that there were no significant bias between the methods although Asset was not in agreement with MAMA-Swin (95% confidence interval above the ±20% criteria). Significant correlations (P < 0.05) were observed between airborne MDI concentration levels and their distribution within the Asset (denuder vs. end filter) and impinger (collecting solution vs. backup filter) subsections. The presence of impregnated inner walls in the CFC did not increase collection efficiency for the generated MDI aerosol. Non-uniform MAMA impregnation on GFF was demonstrated, whereas the collected MDI was evenly distributed in the air samples. These results provided the basis of comparison for other studies involving more complex isocyanate emissions.

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使用实验室生成系统的亚甲基二苯基二异氰酸酯 (MDI) 综合评价方法比较

异氰酸酯是必须在职业环境中进行评估的反应性半挥发性污染物，需要特定的评估方法来应对与异氰酸酯排放特性相关的挑战。存在几种标准方法，但在工业异氰酸酯排放的多样性方面仍然存在显着差异。本研究提出了一种方法来建立三种抽样原则的基线比较。使用实验室生成系统( ⁿ= 31 代实验）。采用以下四种方法测量空气中的 MDI，重点是采样器内收集到的 MDI 的空间分布：(1) Swinnex 盒 13 mm，玻璃纤维过滤器 (GFF)，9-(N-甲基氨基甲基)蒽 ( MAMA ) -斯温）；(2) 封闭面暗盒 (CFC) 37 mm，GFF（末端过滤器和内壁），MAMA-37；(3) 撞击剂和备用 GGF、1,2-甲氧基苯基哌嗪 (MP) (ISO 16702/MDHS 25)；(4) 剥离剂和 GFF（资产 EZ4-NCO）、二丁胺 (DBA) (ISO 17334-1)。Bland 和 Altman 分析确定，尽管 Asset 与 MAMA-Swin 不一致（95% 置信区间高于 ±20% 标准），但这些方法之间没有显着偏差。显着相关性 ( P< 0.05) 在空气中的 MDI 浓度水平及其在资产（扩散器与末端过滤器）和撞击器（收集溶液与备用过滤器）小节中的分布之间观察到。CFC 中浸渍内壁的存在并没有提高生成的 MDI 气溶胶的收集效率。证明了 GFF 上的非均匀 MAMA 浸渍，而收集的 MDI 均匀分布在空气样本中。这些结果为涉及更复杂的异氰酸酯排放的其他研究提供了比较基础。