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首页> 外文期刊>Atmospheric chemistry and physics >Oxidative potential of ambient water-soluble PMsub2.5/sub in the southeastern United States: contrasts in sources and health associations between ascorbic acid (AA) and dithiothreitol (DTT) assays
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Oxidative potential of ambient water-soluble PMsub2.5/sub in the southeastern United States: contrasts in sources and health associations between ascorbic acid (AA) and dithiothreitol (DTT) assays

机译：美国东南部环境水溶性PM 2.5 的氧化潜力：抗坏血酸（AA）和二硫苏糖醇（DTT）分析之间的来源和健康关联的对比

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The ability of certain components of particulate matter to induce oxidative stress through the generation of reactive oxygen species?(ROS) in vivo may be one mechanism accounting for observed linkages between ambient aerosols and adverse health outcomes. A variety of assays have been used to measure this so-called aerosol oxidative potential. We developed a semi-automated system to quantify oxidative potential of filter aqueous extracts utilizing the dithiothreitol?(DTT) assay and report here the development of a similar semi-automated system for the ascorbic acid?(AA) assay. Approximately 500?PMsub2.5/sub filter samples collected in contrasting locations in the southeastern US were analyzed for a host of aerosol species, along with AA and DTT activities. We present a detailed contrast in findings from these two assays. Water-soluble AA activity was higher in summer and fall than in winter, with highest levels near heavily trafficked highways, whereas DTT activity was higher in winter compared to summer and fall and more spatially homogeneous. AA activity was nearly exclusively correlated with water-soluble Cu (ir/i??=??0.70–0.94 at most sites), whereas DTT activity was correlated with organic and metal species. Source apportionment models, positive matrix factorization?(PMF) and a chemical mass balance method with ensemble-averaged source impact profiles?(CMB-E), suggest a strong contribution from traffic emissions and secondary processes (e.g., organic aerosol oxidation or metals mobilization by secondary acids) to both AA and DTT activities in urban Atlanta. In contrast, biomass burning was a large source for DTT activity, but insignificant for AA. AA activity was not correlated with PMsub2.5/sub mass, while DTT activity co-varied strongly with mass (ir/i??=??0.49–0.86 across sites and seasons). Various linear models were developed to estimate AA and DTT activities for the central Atlanta Jefferson Street site, based on the CMB-E sources. The models were then used to estimate daily oxidative potential at this site over the 1998–2009 period. Time series epidemiological analyses were conducted to assess daily emergency department?(ED) visits data for the five-county Atlanta metropolitan area based on the estimated 10-year backcast oxidative potential. Estimated AA activity was not statistically associated with any tested health outcome, while DTT activity was associated with ED visits for both asthma or wheeze and congestive heart failure. The findings point to the importance of both organic components and transition metals from biomass burning and mobile sources to adverse health outcomes in this region.
机译：体内某些微粒物质通过产生活性氧（ROS）诱导氧化应激的能力可能是解释环境气溶胶与不良健康结局之间存在联系的一种机制。已经使用多种测定法来测量这种所谓的气溶胶氧化电位。我们开发了一种半自动化系统，以利用二硫苏糖醇？（DTT）测定法定量过滤水提取物的氧化电位，并在此报告了抗坏血酸？（AA）测定法类似半自动化系统的开发。分析了在美国东南部不同地点收集的大约500µPM 2.5 过滤器样品，分析了其中的大量气溶胶物种以及AA和DTT活性。我们在这两种测定的发现中给出了详细的对比。夏季和秋季的水溶性AA活性高于冬季，在交通繁忙的高速公路附近水平最高，而冬季相比，夏季和秋季的DTT活性较高，并且空间均匀性更高。 AA活性几乎完全与水溶性Cu相关（大多数位置处 r Δε＝ 0.70-0.94），而DTT活性与有机和金属种类相关。源分配模型，正矩阵分解？（PMF）和具有整体平均源影响剖面？（CMB-E）的化学物质平衡方法，表明交通排放和次级过程（例如有机气溶胶氧化或金属动员）的巨大贡献（通过仲酸）到亚特兰大市区的AA和DTT活动。相反，生物质燃烧是DTT活性的主要来源，但对AA而言却微不足道。 AA活性与PM 2.5 的质量无关，而DTT活性与质量的相关性却很强（在整个站点和季节， r Δε= 0.49〜0.86）。根据CMB-E来源，开发了各种线性模型来估计亚特兰大杰斐逊街中心站点的AA和DTT活动。然后使用这些模型估算1998年至2009年期间该站点的日氧化电位。进行了时间序列流行病学分析，以根据估计的10年反向氧化潜力估算亚特兰大五县市区的日常急诊就诊数据。估计的AA活性与经测试的任何健康结局在统计学上均无关联，而DTT活性与因哮喘或喘息和充血性心力衰竭而进行的急诊就诊相关。研究结果指出，从该生物质燃烧和流动源中获取有机成分和过渡金属对于该地区不利的健康状况均具有重要意义。

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