Department of Civil and Environmental Engineering, University of Southern California , Los Angeles, California, United States.
Environ Sci Technol. 2014 Jul 1;48(13):7576-83. doi: 10.1021/es500937x. Epub 2014 Jun 10.
An emerging hypothesis in the field of air pollution is that oxidative stress is one of the important pathways leading to adverse health effects of airborne particulate matter (PM). To advance our understanding of sources and chemical elements contributing to aerosol oxidative potential and provide global comparative data, we report here on the biological oxidative potential associated with size-segregated airborne PM in different urban areas of the world, measured by a biological (cell-based) reactive oxygen species (ROS) assay. Our synthesis indicates a generally greater intrinsic PM oxidative potential as well as higher levels of exposure to redox-active PM in developing areas of the world. Moreover, on the basis of our observations, smaller size fractions are generally associated with higher intrinsic ROS activity compared with larger PM size fractions. Another important outcome of our study is the identification of major species and sources that are associated with ROS activity. Water-soluble transition metals (e.g., Fe, Ni, Cu, Cr, Mn, Zn and V) and water-soluble organic carbon (WSOC) showed consistent correlations with the oxidative potential of airborne PM across different urban areas and size ranges. The major PM sources associated with these chemical species include residual/fuel oil combustion, traffic emissions, and secondary organic aerosol formation, indicating that these sources are major drivers of PM-induced oxidative potential. Moreover, comparison of ROS activity levels across different seasons indicated that photochemical aging increases the intrinsic oxidative potential of airborne PM.
在空气污染领域，有一个新兴假说认为，氧化应激是空气中颗粒物（PM）导致不良健康影响的重要途径之一。为了深入了解导致气溶胶氧化潜力的来源和化学元素，并提供全球比较数据，我们在此报告了通过生物（基于细胞）活性氧（ROS）测定法，对世界不同城市地区按粒径大小分级的空气中可吸入颗粒物（PM）的生物氧化潜力。我们的综合研究表明，发展中地区的空气中可吸入颗粒物的固有氧化潜力普遍较大，且更易接触到具有氧化还原活性的 PM。此外，根据我们的观察，与较大的 PM 粒径相比，较小的粒径通常与更高的固有 ROS 活性相关。我们研究的另一个重要结果是确定了与 ROS 活性相关的主要物质和来源。水溶性过渡金属（如 Fe、Ni、Cu、Cr、Mn、Zn 和 V）和水溶性有机碳（WSOC）与不同城市地区和粒径范围内的空气 PM 氧化潜力呈一致相关性。与这些化学物质相关的主要 PM 来源包括残余/燃油燃烧、交通排放和二次有机气溶胶形成，这表明这些来源是 PM 诱导氧化潜力的主要驱动因素。此外，对不同季节 ROS 活性水平的比较表明，光化学老化会增加空气中可吸入颗粒物的固有氧化潜力。
