Chemical Composition of Secondary Organic Aerosol Formed from the Oxidation of Semivolatile Isoprene Epoxydiol Isomerization Products
Year: 2024
Type: article
Abstract: 3-Methylenebutane-1,2,4-triol and 3-methyltetrahydrofuran-2,4-diols, previously designated “C 5 -alkene triols”, were recently confirmed as in-particle isomerization products of isoprene-derived β-IEPOX isomers that are formed upon acid-driven uptake and partition back into the gas phase. In chamber experiments, we have systematically explored their gas phase oxidation by hydroxyl radical ( • OH) as a potential source of secondary organic aerosol (SOA). • OH-initiated oxidation of both compounds in the presence of ammonium bisulfate aerosol resulted in substantial aerosol volume growth. Compositions of low-volatility products in both the gas and particulate phases were established by high-resolution mass spectrometry measurements. Under conditions mimicking the Southeast USA (50% relative humidity, bulk seed aerosol pH 1.4), we estimate the SOA yield from • OH-initiated oxidation of 3-methylenebutane-1,2,4-triol to be 93.1%, equating to 1.95 ± 0.81 Tg C Yr -1, and from 3-methyltetrahydrofuran-2,4-diol oxidation to be 26.7%, equating to 1.76 ± 1.26 Tg C Yr -1 . Previously unreported isoprene-derived oxidation products, 2,3-dihydroxy-2-(hydroxymethyl)propanal, 1,3,4-trihydroxybutan-2-one, and four organosulfates have been confirmed in ambient SOA, and aid in understanding isoprene oxidation pathways in HO 2 • dominated environments as NO x levels continue to decline in the US. This work underlines the need for inclusion of partitioning of in-particle formed semivolatile products and their atmospheric oxidation pathways in atmospheric models.
Language: English
Subfield: Atmospheric Science
Field: Earth and Planetary Sciences
Domain: Physical Sciences
Open Access status: green
Awards: Early-Generation Photochemical Oxidation Products of Isoprene Under Low-NO Conditions:Aerosol Formation Potential and Structural Assignments by Ion Mobility Mass Spectral Analysis, G2270143745, G468512633, G5721591118, Comparison of Thermal and Non-Thermal Protocols for Analysis of Isoprene Secondary Organic Aerosol (SOA) Generated under Conditions of Low Nitrogen Oxides (NOx), The UNC Chapel Hill Superfund Research Program (UNC-SRP)
OpenAlex ID: W4405314430