Evaluation of reaction between SO2 and CH2OO in MCM mechanism against smog chamber data from ethylene ozonolysis

IF 1.8 4区环境科学与生态学 Q3 CHEMISTRY, ANALYTICAL

Environmental Chemistry Pub Date : 2023-12-03 DOI:10.1071/en23029

Hailiang Zhang, Long Jia, Yongfu Xu

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引用次数: 0

Abstract

Environmental context The process of ethylene ozonolysis is an essential source of CH2OO radicals, and the latter is an important oxidant for the atmospheric pollutant SO2. The accuracy of a widely used atmospheric chemistry model (Master Chemical Mechanism, MCM) in quantifying SO2 oxidation has not been evaluated. In this study, this accuracy was evaluated, and optimal parameters underpinned by data from smog chamber experiments. Rationale The oxidation of SO2 by CH2OO radicals in the ethylene-O3 system is one of the important pathways of sulfate aerosol formation, but the accuracy of Master Chemical Mechanism (MCM) simulation for this reaction was not evaluated, although the MCM has been widely used in previous studies. Methodology The oxidation of SO2 in the ethylene-O3 system was performed in detail under different conditions, which were used to evaluate the accuracy of MCM simulation for the reactions in this study. Results The experimental conditions of low RH and high initial SO2 concentration favour the SO2 oxidation in the ethylene ozonolysis, and the yield of CH2OO in the ethylene ozonolysis without irradiations was determined to be 0.43. The n-hexane (C6H14) oxidation intermediates can promote the SO2 oxidation rate by generating sulfur-containing organics in the aerosol water. The original MCM simulated SO2 consumption after 4-h reaction was more than 70% smaller than the measured results. By adjusting the yield of CH2OO and updating the reaction rate constants of CH2OO-related reactions (e.g. with SO2, H2O and organic acid), the difference between experiments and simulations decreased from 70% to 6.6%. Discussion The promotion effects of n-hexane on the oxidation of SO2 suggest that alkanes may be the precursors of sulfur-containing organics in the atmospheric environment. This study further confirms the effect of CH2OO on the oxidation of SO2 in the atmospheric environment and provides information on the performance of MCM simulation.

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MCM机制中SO2与ch260的反应与乙烯臭氧分解烟雾室数据的评价

乙烯臭氧分解过程是ch2o自由基的重要来源，而后者是大气污染物SO2的重要氧化剂。一种广泛使用的大气化学模型（Master Chemical Mechanism， MCM）在量化SO2氧化方面的准确性尚未得到评估。在本研究中，评估了这种准确性，并根据雾霾室实验数据确定了最佳参数。SO2在乙烯- o3体系中被ch260自由基氧化是硫酸盐气溶胶形成的重要途径之一，但MCM （Master Chemical Mechanism）模拟该反应的准确性尚未得到评估，尽管MCM在以往的研究中得到了广泛的应用。方法对SO2在乙烯- o3体系中不同条件下的氧化过程进行了详细的模拟，并对MCM模拟的准确性进行了评价。结果低相对湿度和高初始SO2浓度的实验条件有利于乙烯臭氧分解过程中SO2的氧化，确定了不辐照的乙烯臭氧分解过程中ch260的产率为0.43。正己烷（C6H14）氧化中间体通过在气溶胶水中生成含硫有机物来促进SO2的氧化速率。原始MCM模拟反应4 h后的SO2消耗量比实测结果小70%以上。通过调整ch2o的产率和更新ch2o相关反应（如SO2、H2O和有机酸）的反应速率常数，实验与模拟的差异从70%减小到6.6%。正己烷对SO2氧化的促进作用表明，烷烃可能是大气环境中含硫有机物的前体。本研究进一步证实了ch220对大气环境中SO2氧化的影响，并为MCM模拟的性能提供了信息。

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来源期刊

Environmental Chemistry 环境科学-分析化学

CiteScore

4.50

自引率

0.00%

发文量

审稿时长

2.7 months

期刊介绍： Environmental Chemistry publishes manuscripts addressing the chemistry of the environment (air, water, earth, and biota), including the behaviour and impacts of contaminants and other anthropogenic disturbances. The scope encompasses atmospheric chemistry, geochemistry and biogeochemistry, climate change, marine and freshwater chemistry, polar chemistry, fire chemistry, soil and sediment chemistry, and chemical aspects of ecotoxicology. Papers that take an interdisciplinary approach, while advancing our understanding of the linkages between chemistry and physical or biological processes, are particularly encouraged. While focusing on the publication of important original research and timely reviews, the journal also publishes essays and opinion pieces on issues of importance to environmental scientists, such as policy and funding. Papers should be written in a style that is accessible to those outside the field, as the readership will include - in addition to chemists - biologists, toxicologists, soil scientists, and workers from government and industrial institutions. All manuscripts are rigorously peer-reviewed and professionally copy-edited. Environmental Chemistry is published with the endorsement of the Commonwealth Scientific and Industrial Research Organisation (CSIRO) and the Australian Academy of Science.