Identification of highly oxygenated organic molecules and their role in aerosol formation in the reaction of limonene with nitrate radical

Abstract. Nighttime NO3-initiated oxidation of biogenic volatile organic compounds (BVOCs) such as monoterpenes is important for the atmospheric formation and growth secondary aerosol (SOA), which has significant impact on climate, air quality, human health. In SOA growth, highly oxygenated molecules (HOM) may be crucial, but their pathways role in have yet to clarified. Among monoterpenes, limonene particular interest its high emission globally yield. this work, HOM reaction with nitrate radical (NO3) was investigated SAPHIR chamber (Simulation Atmospheric PHotochemistry a large Reaction chamber). About 280 products were identified, grouped into 19 monomer families, 11 dimer 3 trimer families. Both closed-shell open-shell peroxy radicals (RO2⚫) observed, many them not been reported previously. Monomers dimers accounted 47 % concentrations, respectively, trimers making up remaining 6 %. most abundant C10H15−17NO6−14, carbonyl outnumbered hydroxyl products, indicating importance RO2⚫ termination by unimolecular dissociation. autoxidation alkoxy–peroxy found processes leading HOM. Time-dependent concentration profiles containing nitrogen showed mainly second-generation patterns. Dimers likely formed via accretion two RO2⚫, HOM-trimers between RO2⚫. Trimers are suggested play an new particle (NPF) observed our experiment. A yield 1.5%-0.7%+1.7% estimated considering only first-generation products. mass could reasonably explained condensation particles assuming irreversible uptake ultra-low volatility (ULVOCs), extremely low (ELVOCs), (LVOCs). This work provides evidence +NO3 NPF particles.