光照下生物质燃烧产生的颗粒物上被忽视的环境持久性自由基的形成。

The overlooked formation of environmentally persistent free radicals on particulate matter collected from biomass burning under light irradiation.

作者信息

Guo Huibin, Wang Yidan, Yao Kaixing, Zheng Han, Zhang Xinji, Li Rui, Wang Ning, Fu Haiyan

机构信息

Department of Environmental Engineering, Xiamen University of Technology, Xiamen 361024, China.

Department of Environmental Engineering, Xiamen University of Technology, Xiamen 361024, China.

出版信息

Environ Int. 2023 Jan;171:107668. doi: 10.1016/j.envint.2022.107668. Epub 2022 Nov 29.

DOI:10.1016/j.envint.2022.107668

Abstract

BACKGROUND

The illumination process may be an important contributor to environmentally persistent free radicals (EPFRs) in atmospheric particles, but the ability of light to generate EPFRs in combustion products remains unclear.

OBJECTIVE

This paper studies the characteristics and formation mechanism of EPFRs in combustion particles after photoexcitation.

METHOD

The secondary photochemical processes and the generation and decay capability of EPFRs in size-resolved (<10 µm) biomass combustion particles were analysed by electron paramagnetic resonance (EPR) spectroscopy.

RESULT

Our results indicated that secondary EPFRs can be generated after illumination and the produced EPFRs have a lifetime of approximately 1 day. The content of secondary EPFRs after light exposure increased by 20 %-30 % compared to that of the original EPFRs. Through the analysis of components of different polarities, it was found that non-extractable substances were the main contributors to secondary EPFRs (75 %), followed by extractable organics. This study showed that metal species and quinones are important precursors for the formation of secondary EPFRs from non-extractable and extractable PM components, respectively. We found that O molecules are an important factor for the formation of secondary EPFRs from organic substances without oxygen functional groups.

CONCLUSIONS

This study presents information about the effects of light and O on the generation of EPFRs, and the unstable nature of secondary EPFRs has important implications for assessing the health risks of atmospheric particles.

摘要

背景

光照过程可能是大气颗粒物中环境持久性自由基（EPFRs）的一个重要来源，但光在燃烧产物中产生EPFRs的能力仍不明确。

目的

本文研究光激发后燃烧颗粒物中EPFRs的特性及形成机制。

方法

采用电子顺磁共振（EPR）光谱分析了不同粒径（<10 µm）生物质燃烧颗粒物中EPFRs的二次光化学过程及其产生和衰减能力。

结果

我们的结果表明，光照后可产生二次EPFRs，所产生的EPFRs的寿命约为1天。光照后二次EPFRs的含量比原始EPFRs增加了20%-30%。通过对不同极性成分的分析发现，不可萃取物质是二次EPFRs的主要贡献者（75%），其次是可萃取有机物。本研究表明，金属物种和醌分别是不可萃取和可萃取颗粒物成分形成二次EPFRs的重要前体。我们发现，O分子是无氧官能团有机物形成二次EPFRs的重要因素。

结论

本研究提供了有关光和O对EPFRs生成影响的信息，二次EPFRs的不稳定性对评估大气颗粒物的健康风险具有重要意义。