首页> 外文期刊>Analytical and bioanalytical chemistry >Baltimore PM2.5 Supersite: Highly time-resolved organic compounds-sampling duration and phase distribution-implications for health effects studies
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Baltimore PM2.5 Supersite: Highly time-resolved organic compounds-sampling duration and phase distribution-implications for health effects studies

机译:巴尔的摩PM2.5超级站点:高度时间分辨的有机化合物-采样持续时间和相分布-对健康影响研究的意义

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摘要

As part of the Baltimore PM2.5 Supersite study, intensive three-hourly continuous PM2.5 sampling was conducted for nearly 4 weeks in summer of 2002 and as well in winter of 2002/2003. Close to 120 individual organic compounds have been quantified separately in filter and polyurethane foam (PUF) plug pairs for 17 days for each sampling period. Here, the focus is on (1) describing briefly the new sampling system, (2) discussing filter/PUF plugs breakthrough experiments for semi-volatile compounds, (3) providing insight into phase distribution of semi-volatile organic species, and (4) discussing the impact of air pollution sampling time on human exposure with information on maximum 3- and 24-h averaged ambient concentrations of potentially adverse health effects causing organic pollutants. The newly developed sampling system consisted of five electronically controlled parallel sampling channels that are operated in a sequential mode. Semi-volatile breakthrough experiments were conducted in three separate experiments over 3, 4, and 5 h each using one filter and three PUF plugs. Valuable insight was obtained about the transfer of semi-volatile organic compounds through the sequence of PUF plugs and a cut-off could be defined for complete sampling of semi-volatile compounds on only one filter/PUF plug pair, i.e., the setup finally used during the seasonal PM2.5 sampling campaign. Accordingly, n-nonadecane (C19) with a vapor pressure (vp) of 3.25∈×∈10~(-4) Torr is collected with > 95% on the filter/PUF pair. Applied to phenanthrene, the most abundant the PAH sampled, phenanthrene (vp, 6.2∈×∈10~(-5) Torr) was collected completely in wintertime and correlates very well with three-hourly PM2.5 ambient concentrations. Valuable data on the fractional partitioning for semi-volatile organics as a function of season is provided here and can be used to differentiate the human uptake of an organic pollutant of interest via gas- and particle-phase exposure. Health effects studies often relay on PM2.5 exposure measurements taken over 24 h or longer. We found that maximum 3-h concentrations are frequently two to five times higher than that found for maximum 24-h concentrations, an important aspect when considering that short-term exposure to higher air pollution levels are more likely to overpower defense mechanisms in the human lung with subsequent adverse effects even at lower pollutant levels.
机译:作为巴尔的摩PM2.5超级站点研究的一部分,在2002年夏季和2002/2003年冬季进行了将近3周的连续三小时PM2.5密集采样。在每个采样周期中,将近120种单独的有机化合物分别在过滤器和聚氨酯泡沫(PUF)塞对中进行了17天的定量分析。在这里,重点是(1)简要描述新的采样系统;(2)讨论半挥发性化合物的过滤器/ PUF塞突破性实验;(3)深入了解半挥发性有机物的相分布;以及(4) )讨论空气污染采样时间对人体暴露的影响,并提供有关可能导致健康有机污染物的有害健康影响的最大3小时和24小时平均环境浓度的信息。新开发的采样系统由五个电子控制的并行采样通道组成,这些通道以顺序模式运行。在三个独立的实验中,分别使用一个过滤器和三个PUF塞子分别在3、4和5小时内进行了半挥发性突破实验。对于通过PUF阀塞的顺序转移半挥发性有机化合物获得了宝贵的见识,可以定义一个临界值,以便仅在一个过滤器/ PUF阀塞对上对半挥发性化合物进行完全采样,即最终使用的装置在季节性PM2.5采样活动中。因此,在过滤器/ PUF对上收集到蒸气压(vp)为3.25ε×ε10〜(-4)Torr的n-十八碳烯(C19),其中> 95%。在菲中,PAH样品中含量最丰富的菲(vp,6.2ε×ε10〜(-5)Torr)在冬季完全被收集,并且与三小时的PM2.5环境浓度有很好的相关性。此处提供了有关随季节变化的半挥发性有机物分数分配的重要数据,这些数据可用于区分人类通过气相和颗粒相对有机污染物的摄入量。健康影响研究通常会基于24小时或更长时间进行的PM2.5暴露测量。我们发现最大3小时浓度通常比最大24小时浓度高出2至5倍,这是考虑到短期暴露于较高空气污染水平更有可能破坏人类防御机制的重要方面甚至在较低的污染物水平下也会对肺造成不良影响。

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