Changes in Secondary Organic Aerosol Composition and Volatility Going from a Low to a High HO₂/RO₂ Regime in α‑Pinene Photooxidation.

ABSTRACT: The mechanisms of secondary organic aerosol (SOA) formation are not yet fully understood. The relative abundance of hydroperoxyl radicals (HO₂) and peroxy radicals (RO₂) affects SOA properties, but chamber experiments often underemphasize the role of HO₂. To clarify their contribution, this study compares the composition and volatility of SOA formed by the hydroxyl radical (OH) oxidation of α-pinene under low and high HO₂/RO₂ regimes with a constant OH concentration. The particle-phase was characterized with a Filter Inlet for Gases and AEROsols coupled to an iodide Chemical Ionization Mass Spectrometer (FIGAERO CIMS), and a CIMS with NO₃ ^- ionization was used for gas-phase measurements. High HO₂/RO

SUBMITTER: Geretti V 

PROVIDER: S-EPMC12797231 | biostudies-literature | 2026 Jan

REPOSITORIES: biostudies-literature