HONO, a key sink of Isoprene-derived Criegee Intermediates (MACR-oxide and MVK-oxide)

Abstract

In the present work, we investigated the bimolecular reactions of biogenic (MVK-OO and MACR-OO) and anthropogenic (CH 3 CHOO) Criegee intermediates with HONO using high level quantum chemical calculations and kinetic modelling. For quantum chemical calcu- lations, we used the CCSD(T)/CBS//M06-2X/aug-cc-pVTZ level of theory, while for the rate constant calculation, we used Rice-Ramsperger-Kassel-Marcus theory/master equation kinetics calculations. Our study suggests that HONO can serve as a major bimolecular sink for MVK-OO, whereas it acts as a minor sink for MACR-OO, becoming significant only under low-humidity and low-temperature conditions. For CH 3 CHOO, HONO acts as the most dominant sink after unimolecular decay. Overall, the findings suggest that HONO can act as a potential sink for Criegee intermediates in both biogenic (forested) and anthropogenic (urban) environments.