Probing the Large Discrepancy of Highly Oxygenated Organic Molecules and Secondary Organic Aerosol Formation from Atmospheric Oxidation of Nerolidol by OH, NO ₃ , and O ₃

Nerolidol is an important sesquiterpenol widely present in cosmetics and plant-emitted vapors, and its intricate oxidation process contributes to atmospheric secondary organic aerosol (SOA). Herein, the detailed atmospheric oxidation mechanisms of nerolidol by OH, NO₃, and O₃ were investigated, especially the formation of highly oxygenated organic molecules (HOMs). Based on the time-dependent yields of main products (including HOMs) derived from the newly established zero-dimensional box model and their volatility evaluation, screening out the pivotal components in SOA formation, the theoretical SOA yields were therefore determined for different atmospheric conditions (indoor, daytime, and nighttime in the forest). The presence of multiple double bonds within the first-generation oxidation products is the key factor for the subsequent generation of HOMs from the oxidation of nerolidol by OH, NO₃, and O₃, resulting in several repetitive reaction sequences occurring to increase the molecular weight of the products. The formation of HOMs induced by OH is derived from the introduction of OH and OOH groups to the multiple double bonds of nerolidol. A new extended autoxidation mechanism is proposed for HOM generation from NO₃-initiated oxidation of nerolidol, i.e., NO₃ + RO₂ → RO, RO → R'O via H shift and R'O + O₂ → R'O₂. The multiple association of Crigee radicals with carbonyl compounds formed by primary ozonides decomposition eventually generates HOMs, with the low final yield (<0.001). The theoretical SOA yields show significant differences among the three atmosphere conditions (indoor: 4%, daytime in the forest: 61%, nighttime in the forest: 91%), which highlights the importance of consideration of the cross-oxidation among OH, NO₃, and O₃ and the oxidation degree of multigeneration products in the model refinement.