Physical and chemical characterization of atmospheric ultrafine particles in the Los Angeles area
Physical and chemical characterization of atmospheric ultrafine particles in the Los Angeles area
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DOI：
10.1021/es970280r
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发表时间：
1998-05-01
影响因子：
11.4
通讯作者：
Olmez, I
中科院分区：
文献类型：
--
作者：
Hughes, LS;Cass, GR;Olmez, I
吸入毒理学家正在研究大气超细颗粒（直径<0.1μm），以确定它们是否对公众健康构成威胁，但人们对城市大气中超细颗粒的化学成分知之甚少。在目前的工作中，大气超细颗粒的数量浓度、尺寸分布和化学成分是在洛杉矶附近的加利福尼亚州帕萨迪纳市冬季条件下测定的。这些实验是使用扫描差分迁移率分析仪、激光光学计数器和两个微孔冲击器进行的。对样品进行分析，以建立超细颗粒化学成分的物质平衡。经过 24 小时的分析，发现尺寸范围 0.017 < d(p) < 0.1 μ m 的超细颗粒的数量浓度始终在 1.3 x 10(4) +/- 8.9 x 10(3) 颗粒 cm(-3) 空气范围内。超细颗粒质量浓度范围为0.80-1.58μg·m(-3)。有机化合物是超细颗粒质量浓度的最大贡献者。这些颗粒中存在少量硫酸盐，其浓度太低，无法判断其是否以未中和的硫酸形式存在。铁是超细颗粒中最突出的过渡金属。这些数据可以帮助健康影响研究界构建涉及超细颗粒的现实动物或人类暴露研究。
Atmospheric ultrafine particles (diameter < 0.1 mu m) are under study by inhalation toxicologists to determine whether they pose a threat to public health, yet, little is known about the chemical composition of ultrafine particles in the atmosphere of cities. In the present work, the number concentration, size distribution, and chemical composition of atmospheric ultrafine particles is determined under wintertime conditions in Pasadena, CA, near Los Angeles. These experiments are conducted using a scanning differential mobility analyzer, laser optical counter, and two micro-orifice impactors. Samples are analyzed to create a material balance on the chemical composition of the ultrafine particles. The number concentration of ultrafine particles in the size range 0.017 < d(p) < 0.1 mu m, analyzed over 24-h periods, is found to be consistently in the range 1.3 x 10(4) +/- 8.9 x 10(3) particles cm(-3) air. Ultrafine particle mass concentrations are in the range 0.80-1.58 mu g m(-3). Organic compounds are the largest contributors to the ultrafine particle mass concentration. A small amount of sulfate is present in these particles, at concentrations too low to tell whether it exists as unneutralized sulfuric acid. Iron is the most prominent transition metal found in the ultrafine particles. These data may assist the health effects research community in constructing realistic animal or human exposure studies involving ultrafine particles.