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Electrical Discharges Produce Prodigious Amounts of Hydroxyl and Hydroperoxyl Radicals
Author(s) -
Jenkins Jena M.,
Brune William H.,
Miller David O.
Publication year - 2021
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
eISSN - 2169-8996
pISSN - 2169-897X
DOI - 10.1029/2021jd034557
Subject(s) - hydroperoxyl , ozone , hydroxyl radical , radical , water vapor , atmosphere (unit) , chemistry , troposphere , mixing ratio , volume (thermodynamics) , vapour pressure of water , atmospheric pressure , analytical chemistry (journal) , nitrogen , atmospheric chemistry , vapor pressure , environmental chemistry , meteorology , organic chemistry , thermodynamics , physics
Reaction with the hydroxyl radical (OH) is often the first step in the removal of many atmospheric pollutants. The nitrogen oxides (NO x ) generated by lightning can increase the amount of HO x (HO x = OH + HO 2 ) present in the atmosphere, but direct HO x production from lightning has never been quantitatively investigated in the laboratory. In this laboratory study, prodigious amounts of HO x 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 (NO x ), ozone (O 3 ), and OH exposure, which is the integral of the hydroxyl radical concentration over time since the discharge. HO x 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 NO x was approximately independent of both pressure and water vapor over the same ranges. These laboratory measurements of excessive HO x and OH exposure are similar to measurements of electrically generated HO x 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 HO x contribution to atmospheric oxidation.