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Long-life type- The dominant fraction of EPFRs in combustion sources and ambient fine particles in Xi'an

机译：长寿命型-西安市燃烧源和环境细颗粒中EPFR的主要成分

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摘要

Environmentally persistent free radicals (EPFRs) are new environmental health risk substances that have received much attention in recent years. The characterization of EPFR5 is essential for understanding their sources and formation mechanisms in atmospheric particulate matter (PM), yet their physicochemical characteristics have not yet been fully and extensively studied. To clarify the nature of "persistent" free radicals in atmospheric PM, we systematically evaluated the decay characteristics of EPFRs in both combustion sources and ambient PM2.5 based on the planned measurement of EPFRs in a large number of samples (more than 130). The content of EPFRs changed over time for up to 2 years. This study quantifies EPFRs with different lifetimes in different sources of PM2.5. The results indicate that the EPFRs were dominated by the long-life type (>70%), with a 1/e lifetime of several years, in both combustion sources and ambient PM2.5. The decay characteristics of the EPFRs, including the temporal variations in the concentrations and g-factors of EPFRs in ambient PM2.5, were similar to those of combustion source samples but different from those of EPFRs produced by the interaction of metal oxides and aromatics. The interaction of metal oxides and aromatics may produce short-life EPFRs, and the formation mechanism of long-life EPFRs may be more complicated. This study provides important basic knowledge for understanding the sources and formation mechanisms of EPFRs in atmospheric PM.
机译：持久性环境自由基（EPFRs）是近年来危害环境健康的新物质。 EPFR5的表征对于了解其在大气颗粒物（PM）中的来源和形成机理至关重要，但是其理化特性尚未得到充分而广泛的研究。为了阐明大气PM中“持久性”自由基的性质，我们基于对大量样品（超过130个）中EPFR的计划测量，系统地评估了燃烧源和环境PM2.5中EPFR的衰减特性。 EPFR的含量随时间变化最多2年。这项研究量化了不同来源的PM2.5中具有不同寿命的EPFR。结果表明，在燃烧源和环境PM2.5中，EPFR均以长寿命类型（> 70％）为主，其1 / e寿命为数年。 EPFR的衰减特性，包括环境PM2.5中EPFR的浓度和g因子随时间的变化，与燃烧源样品相似，但与由金属氧化物和芳族化合物相互作用产生的EPFR有所不同。金属氧化物和芳族化合物的相互作用可能产生短寿命的EPFR，长寿命的EPFR的形成机理可能更加复杂。这项研究为理解大气PM中EPFR的来源和形成机理提供了重要的基础知识。

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  • 来源
    《Atmospheric environment》 |2019年第12期|117059.1-117059.5|共5页
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    Shaanxi Univ Sci & Technol Sch Environm Sci & Engn Weiyang Dist Xian 710021 Shaanxi Peoples R China;

    Beijing Jiaotong Univ Sch Civil Engn Beijing 100044 Peoples R China;

    Tsinghua Univ Sch Architecture Dept Bldg Sci Beijing 100084 Peoples R China;

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  • 正文语种 eng
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  • 关键词

    PM2.5; EPFRs; Long life; Sources; Formation mechanism;

    机译：PM2.5;EPFR;长寿;资料来源;形成机理;

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