Measurements of hydroperoxy and total organic peroxy radicals in an Indiana forest using laser induced fluorescence - Archive ouverte HAL Accéder directement au contenu
Poster De Conférence Année : 2019

Measurements of hydroperoxy and total organic peroxy radicals in an Indiana forest using laser induced fluorescence

Résumé

The hydroxyl (OH) and hydroperoxy (HO2) radicals, as well as organic peroxy radicals (RO2), play important roles in atmospheric chemistry. The OH radical initiates the oxidation of volatile organic compounds (VOCs), leading to HO2 and RO2 radicals whose chemistry, in the presence of nitrogen oxides (NOx), can lead to the formation of ozone and secondary organic aerosols in the environment. Previous measurements of these radicals in forest environments characterized by high mixing ratios of isoprene and low mixing ratios of NOx have shown serious discrepancies with modeled predictions, bringing into question our understanding of isoprene oxidation in the atmosphere. In the summer of 2019, HOx (=OH+HO2), and ROx (=HO2+RO2) radicals were investigated using Laser Induced Fluorescence-Fluorescence Assay by Gas Expansion (LIF-FAGE) at the Indiana University Teaching and Research Preserve (IURTP) field laboratory. The LIF-FAGE inlet was modified by attaching a 45-cm reactor to convert ROx and HOx species to HO2, similar to the published ROxLIF technique (Fuchs, Holland et al. 2008). The resulting HO2 is then converted to OH and detected inside the LIF-FAGE detection cell. Two different modes (ROx and HOx) are achieved by the addition of carbon monoxide (CO) and nitrogen oxide (NO), with a high conversion efficiency (~40% conversion) under low pressure conditions (~30 Torr) before reaching the detection cell. The ambient HOx and ROx measurements will be compared to model predictions as well as previous measurements of peroxy radical concentrations at this site. In addition to the ambient measurements, laboratory characterizations of the sensitivity of the ROx instrument to various RO2 radicals will be presented.
Fichier principal
Vignette du fichier
AGU 2019_Draft5.pdf (3.03 Mo) Télécharger le fichier
Origine : Fichiers produits par l'(les) auteur(s)

Dates et versions

hal-04300879 , version 1 (24-11-2023)

Identifiants

  • HAL Id : hal-04300879 , version 1

Citer

C.M.F. Rosales, Ahmad Lahib, Brandon Bottorff, Emily K. Reidy, V. Kumar, et al.. Measurements of hydroperoxy and total organic peroxy radicals in an Indiana forest using laser induced fluorescence. AGU Fall Meeting, Dec 2019, San francisco, USA, United States. ⟨hal-04300879⟩
15 Consultations
2 Téléchargements

Partager

Gmail Facebook X LinkedIn More