Electrical Discharges Produce Prodigious Amounts of Hydroxyl and Hydroperoxyl Radicals
Electrical Discharges Produce Prodigious Amounts of Hydroxyl and Hydroperoxyl Radicals
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DOI：
10.1029/2021jd034557
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发表时间：
2021-05-16
影响因子：
4.4
通讯作者：
Miller, David O.
中科院分区：
文献类型：
--
作者：
Jenkins, Jena M.;Brune, William H.;Miller, David O.
与羟基自由基（OH）的反应通常是去除许多大气污染物的第一步。闪电产生的氮氧化物（NOx）可以增加大气中HOx（HOx = OH + HO 2）的含量，但闪电直接产生的HOx还没有在实验室中进行定量研究。在这项实验室研究中，大量的HOx产生的可见光和亚可见光的放电范围内的压力和水蒸气的混合比相关的对流层。还测量了NO、总氮氧化物（NOx）、臭氧（O-3）和OH暴露，OH暴露是自放电以来羟基自由基浓度随时间的积分。从360到970 hPa，HOx和OH暴露大致与压力无关，并且随着水蒸气从1，000增加到8，000 ppm（ppmv），仅略有增加，而NOx在相同范围内大致与压力和水蒸气无关。这些实验室测量的过量HOx和OH暴露类似于2012年空中研究期间在带电砧云中发现的电生成HOx的测量，从而证明了这些实验室结果与大气的相关性以及理解电生成HOx对大气氧化的贡献的重要性。
Reaction with the hydroxyl radical (OH) is often the first step in the removal of many atmospheric pollutants. The nitrogen oxides (NOx) generated by lightning can increase the amount of HOx (HOx = OH + HO2) present in the atmosphere, but direct HOx production from lightning has never been quantitatively investigated in the laboratory. In this laboratory study, prodigious amounts of HOx were generated by both visible and subvisible electrical discharges over ranges of pressure and water vapor mixing ratios relevant to the troposphere. Also measured were NO, total nitrogen oxides (NOx), ozone (O-3), and OH exposure, which is the integral of the hydroxyl radical concentration over time since the discharge. HOx and OH exposure were approximately independent of pressure from 360 to 970 hPa and increased only slightly as water vapor increased from 1,000 to 8,000 parts per million volume (ppmv), while NOx was approximately independent of both pressure and water vapor over the same ranges. These laboratory measurements of excessive HOx and OH exposure are similar to measurements of electrically generated HOx discovered in electrified anvil clouds during a 2012 airborne study, thus demonstrating the relevance of these laboratory results to the atmosphere and the importance of understanding the electrically generated HOx contribution to atmospheric oxidation.