Garcia Alberto, Eastlake Adrienne, Topmiller Jennifer L, Sparks Christopher, Martinez Kenneth, Geraci Charles L
a U.S. Department of Health and Human Services (DHHS), Public Health Service (PHS), Centers for Disease Control and Prevention (CDC) , National Institute for Occupational Safety and Health (NIOSH) , Cincinnati , Ohio.
b Bureau Veritas North America , Houston , Texas.
J Occup Environ Hyg. 2017 Sep;14(9):727-737. doi: 10.1080/15459624.2017.1326699.
In January 2007, the National Institute for Occupational Safety and Health (NIOSH) conducted a field study to evaluate process specific emissions during the production of ENMs. This study was performed using the nanoparticle emission assessment technique (NEAT). During this study, it was determined that ENMs were released during production and cleaning of the process reactor. Airborne concentrations of silver, nickel, and iron were found both in the employee's personal breathing zone and area samples during reactor cleaning. At the completion of this initial survey, it was suggested that a flanged attachment be added to the local exhaust ventilation system. NIOSH re-evaluated the facility in December 2011 to assess worker exposures following an increase in production rates. This study included a fully comprehensive emissions, exposure, and engineering control evaluation of the entire process. This study made use of the nanoparticle exposure assessment technique (NEAT 2.0). Data obtained from filter-based samples and direct reading instruments indicate that reactor cleanout increased the overall particle concentration in the immediate area. However, it does not appear that these concentrations affect areas outside of the production floor. As the distance between the reactor and the sample location increased, the observed particle number concentration decreased, creating a concentration gradient with respect to the reactor. The results of this study confirm that the flanged attachment on the local exhaust ventilation system served to decrease exposure potential. Given the available toxicological data of the metals evaluated, caution is warranted. One should always keep in mind that occupational exposure levels were not developed specifically for nanoscale particles. With data suggesting that certain nanoparticles may be more toxic than the larger counterparts of the same material; employers should attempt to control emissions of these particles at the source, to limit the potential for exposure.
2007年1月，美国国家职业安全与健康研究所（NIOSH）开展了一项实地研究，以评估纳米材料生产过程中的特定工艺排放。该研究采用了纳米颗粒排放评估技术（NEAT）。在这项研究中，确定在工艺反应器的生产和清洁过程中会释放纳米材料。在反应器清洁期间，在员工的个人呼吸区和区域样本中均发现了空气中银、镍和铁的浓度。在这项初步调查结束时，建议在局部排风通风系统中增加一个法兰附件。2011年12月，NIOSH对该设施进行了重新评估，以评估生产率提高后工人的接触情况。这项研究包括对整个过程进行全面的排放、接触和工程控制评估。该研究采用了纳米颗粒接触评估技术（NEAT 2.0）。从基于过滤器的样本和直读仪器获得的数据表明，反应器清理增加了紧邻区域的总体颗粒浓度。然而，这些浓度似乎并未影响生产车间以外的区域。随着反应器与样本位置之间距离的增加，观察到的颗粒数浓度降低，形成了相对于反应器的浓度梯度。这项研究的结果证实，局部排风通风系统上的法兰附件有助于降低接触风险。鉴于所评估金属的现有毒理学数据，有必要谨慎对待。人们应始终牢记，职业接触限值并非专门针对纳米级颗粒制定。有数据表明，某些纳米颗粒可能比相同材料的较大颗粒毒性更大；雇主应尝试从源头上控制这些颗粒的排放，以限制接触风险。
