Fujitani Yuji, Hirano Seishiro
Environmental Nanotoxicology Section, RCER, National Institute for Environmental Studies, Tsukuba, Japan.
Nihon Eiseigaku Zasshi. 2008 May;63(3):663-9. doi: 10.1265/jjh.63.663.
The mass concentrations of airborne particles in the atmospheric, indoor, and industrial environments are regulated by air quality standards. Epidemiological studies show that there are significant positive correlations between particle mass concentrations and adverse health effects. In this context nanoparticles in the air, which are defined as particles with a diameter (Dp) of less than 50 nm or 100 nm for engineered ones, are gaining increasing attention despite a small contribution to the mass of total airborn particles. Contrary to the mass concentration the number concentrations of atmospheric nanoparticles are quite high in most cases. Moreover there is limited toxicological information on nanoparticles, although the deposition rate of nanoparticles in the respiratory region is known to be relatively high. Accordingly there are a lot of debates about what metric is best to depict the size distribution of nanoparticles, number, surface area, or mass. In this paper, we report methods for measurement of nanoparticles on the basis of those metrics. We also report sources of nanoparticle in the environment and occupational settings. The high number concentration of nanoparticles of 20-30 nm modal diameters have been documented at roadsides. Diesel-powered vehicles are major sources of those nanoparticles in the urban atmosphere. Engineered nanoparticles generate in some occupational settings in the handling processes such as bagging and cleaning with vacuum cleaners.
空气质量标准对大气、室内和工业环境中空气传播颗粒的质量浓度进行了规定。流行病学研究表明，颗粒质量浓度与不良健康影响之间存在显著的正相关关系。在此背景下，空气中的纳米颗粒（对于工程纳米颗粒，定义为直径（Dp）小于50纳米或100纳米的颗粒）尽管对空气中颗粒的总质量贡献较小，但却越来越受到关注。与质量浓度相反，大多数情况下大气纳米颗粒的数量浓度相当高。此外，尽管已知纳米颗粒在呼吸区域的沉积率相对较高，但关于纳米颗粒的毒理学信息却很有限。因此，关于用什么指标来最好地描述纳米颗粒的尺寸分布，数量、表面积还是质量，存在很多争论。在本文中，我们报告了基于这些指标测量纳米颗粒的方法。我们还报告了环境和职业环境中纳米颗粒的来源。在路边已记录到模态直径为20 - 30纳米的纳米颗粒数量浓度很高。柴油动力车辆是城市大气中这些纳米颗粒的主要来源。工程纳米颗粒在一些职业环境中的处理过程中产生，如装袋和用真空吸尘器清洁。
