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

The heterogeneous chemistry of NO x in the atmosphere remains incompletely understood, and NO x 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 ( k app ) for reactions of Criegee-intermediate-derived OPs with NO 2 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 NO 2, while exhibiting much lower reactivity toward NO. The measured interfacial rate constants for OP + NO 2 are approximately 3 orders of magnitude larger than those for OP + NO, consistent with preferential NO 2 adsorption at the interface. At atmospherically relevant NO 2 levels (1 ppb), OP lifetimes are reduced to the subsecond time scale, indicating that NO 2 can dominate OP removal under elevated NO x conditions. These findings highlight the importance of interfacial NO 2 chemistry in controlling the fate of Criegee-intermediate-derived OPs in the atmosphere.