Role of Hydroperoxyl Radicals in Heterogeneous Oxidation of Oxygenated Organic Aerosols

Heterogeneous oxidative aging of organic aerosols (OA) occurs ubiquitously in the atmosphere, initiated by oxidants, such as the hydroxyl radicals (•OH). Hydroperoxyl radicals (HO2•) are also an important oxidant in the troposphere, and its gas-phase chemistry has been well studied. However, the role of HO2• in heterogeneous OA oxidation remains elusive. Here, we carry out •OH-initiated heterogeneous oxidation of several OA model systems under different HO2• conditions in a flow tube reactor and characterize the molecular oxidation products using a suite of mass spectrometry instrumentation. By using hydrogen-deuterium exchange (HDX) with thermal desorption iodide-adduct chemical ionization mass spectrometry, we provide direct observation of organic hydroperoxide (ROOH) formation from heterogeneous HO2• and peroxy radicals (RO2•) reactions for the first time. The ROOH may contribute substantially to the oxidation products, varied with the parent OA chemical structure. Furthermore, by regulating RO2• reaction pathways, HO2• also greatly influence the overall composition of the oxidized OA. Last, we suggest that the RO2• + HO2• reactions readily occur at the OA particle interface rather than in the particle bulk. These findings provide new mechanistic insights into the heterogeneous OA oxidation chemistry and help fill the critical knowledge gap in understanding atmospheric OA oxidative aging.

Medienart:

E-Artikel

Erscheinungsjahr:

2024

Erschienen:

2024

Enthalten in:

Zur Gesamtaufnahme - volume:58

Enthalten in:

Environmental science & technology - 58(2024), 10 vom: 12. März, Seite 4727-4736

Sprache:

Englisch

Beteiligte Personen:

Zhang, Wen [VerfasserIn]
Issa, Kassem [VerfasserIn]
Tang, Tiffany [VerfasserIn]
Zhang, Haofei [VerfasserIn]

Links:

Volltext

Themen:

3352-57-6
Aerosols
Hydrogen−deuterium exchange
Hydroxyl Radical
Interfacial chemistry
Journal Article
Mass spectrometry
Organic Chemicals
Organic hydroperoxides
Oxidants
Peroxy radicals

Anmerkungen:

Date Completed 13.03.2024

Date Revised 13.03.2024

published: Print-Electronic

Citation Status MEDLINE

doi:

10.1021/acs.est.3c09024

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM369013492