Extremely Fast Reaction of Criegee-Intermediate-Derived Organic Peroxides with NO ₂ at the Air–Liquid Interface

The heterogeneous chemistry of NOx in the atmosphere remains incompletely understood, and NOx potentially undergoes chemical reactions with organic peroxides (OPs) in the condensed phase. Here, we present a new experimental approach to directly quantify apparent rate constants (kapp) for reactions of Criegee-intermediate-derived OPs with NO₂ and NO at the air-liquid interface. Using OPs derived from representative terpenoids (α-pinene,d-limonene, β-caryophyllene, and α-terpineol), we show that all OPs react extremely rapidly with NO₂, while exhibiting much lower reactivity toward NO. The measured interfacial rate constants for OP + NO₂ are approximately 3 orders of magnitude larger than those for OP + NO, consistent with preferential NO₂ adsorption at the interface. At atmospherically relevant NO₂ levels (1 ppb), OP lifetimes are reduced to the subsecond time scale, indicating that NO₂ can dominate OP removal under elevated NOx conditions. These findings highlight the importance of interfacial NO₂ chemistry in controlling the fate of Criegee-intermediate-derived OPs in the atmosphere.