Redox activity of airborne particulate matter at different sites in the Los Angeles Basin
Redox activity of airborne particulate matter at different sites in the Los Angeles Basin
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DOI：
10.1016/j.envres.2005.01.003
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发表时间：
2005-09-01
影响因子：
8.3
通讯作者：
Froines, JR
中科院分区：
文献类型：
--
作者：
Cho, AK;Sioutas, C;Froines, JR
流行病学研究表明，环境颗粒物 (PM) 与不良健康结果之间存在关联，包括死亡率增加、急诊室就诊以及耽误上学和工作时间。 PM 相关健康影响的机制尚不完全清楚，但正在研究的一个假设是，许多不利的健康影响可能源自氧化应激，氧化应激是由受影响细胞内活性氧 (ROS) 的形成引发的。虽然 PM 的不利影响历来与空气传播有关。 PM 浓度和最近的细颗粒 PM 浓度，我们认为有必要开发一种测定法来定量测量 PM 催化 ROS 生成的能力，作为诱导氧化应激的第一步。 PM 的这种能力可能与周围环境中的不同来源、化学成分以及物理和空间/时间特征有关。与来源和其他因素相关的 ROS 形成能力的测量将与氧化还原活性 PM 的控制具有潜在的相关性。如果氧化应激代表 PM 毒性的相关机制，那么氧化还原活性的测量代表了阐明后续下游过程的第一步。我们开发了一种 PM 氧化还原活性测定方法，利用二硫苏糖醇作为电子源对氧进行还原。我们发现 PM 会催化氧气的还原，并检查了在洛杉矶盆地不同地点收集的 PM 馏分的氧化还原活性的分布和化学特征。研究了用气溶胶浓缩器获得的粗颗粒、细颗粒和超细颗粒的浓缩样品的化学性质和氧化还原活性。超细级分中的氧化还原活性最高，这与表明超细级分最能有效诱导血红素加氧酶表达和消耗细胞内谷胱甘肽的结果一致，这与氧化应激的诱导有关。氧化还原活性与化学成分的比较表明，氧化还原活性与元素碳(r(2) = 0.79)、有机碳(r(2) = 0.53)和苯并苝(r(2) = 0.82)具有合理的相关性，与移动排放源中通常发现的物种一致。 (c) 2005 Elsevier Inc. 保留所有权利。
Epidemiologic studies have shown associations between ambient particulate matter (PM) and adverse health outcomes including increased mortality, emergency room visits, and time lost from school and work. The mechanisms of PM-related health effects are still incompletely understood, but a hypothesis under investigation is that many of the adverse health effects may derive from oxidative stress, initiated by the formation of reactive oxygen species (ROS) within affected cells. While the adverse effects from PM have historically been associated with the airborne. concentration of PM and more recently fine-particle PM, we considered it relevant to develop an assay to quantitatively measure the ability of PM to catalyze ROS generation as the initial step in the induction of oxidative stress. This ability of PM could then be related to different sources, chemical composition, and physical and spatial/temporal characteristics in the ambient environment. The measurement of ROS-forming ability in relation to sources and other factors will have potential relevance to control of redox-active PM. If oxidative stress represents a relevant mechanism of toxicity from PM, the measurement of redox activity represents a first step in the elucidation of the subsequent downstream processes. We have developed an assay for PM redox activity, utilizing the reduction of oxygen by dithiothreitol which serves as an electron source. We have found that PM will catalyze the reduction of oxygen and have examined the distribution and chemical characteristics of the redox activity of PM fractions collected in different sites in the Los Angeles Basin. Samples of concentrated coarse, fine, and ultrafine PM, obtained with aerosol concentrators, were studied with regard to their chemical properties and redox activity. Redox activity was highest in the ultrafine fraction, in agreement with results indicating ultrafines were the most potent toward inducing that heme oxygenase expression and depleting intracellular glutathione, which has relevance to induction of oxidative stress. Comparison of the redox activity with chemical composition showed a reasonable correlation of redox activity with elemental carbon (r(2) = 0.79), organic carbon (r(2) = 0.53), and with benzo[ghi]perylene (r(2) = 0.82), consistent with species typically found in mobile emission sources. (c) 2005 Elsevier Inc. All rights reserved.