Amine Ozonation Products Promote Sulfate Formation and Accelerate New Particle Growth

Abstract. New particle formation (NPF) significantly influences aerosol burden and cloud condensation nuclei in the atmosphere, but whether amine ozonation products retain nucleation activity remains unclear. This study combines quantum chemical calculations and cluster dynamics simulations to investigate how OH‑amine and CHO‑amine promote sulfate formation and subsequent cluster growth. Both type amines are found to dominantly reduce SO₂ hydrolysis barrier in the presence of water clusters, and rate-limiting step is changes to ozonation step. Further analysis of growth pathways reveals NH₂OH and CH₂NOH exhibit flexible multi‑core routes that accelerate progression toward critical sizes, whereas CH₃NHOH and CHO‑amines are largely confined to single‑ or double‑core pathways. Simulations of cluster formation rates show several ozonation products achieve rates comparable to their parent amines, indicating amine‑driven NPF can persist after ozonation rather than terminating with the consumption of the parent species. Humidity strongly activates all systems, while temperature effects diverge sharply. OH‑amine formation rates drop by 3 – 14 orders of magnitude from 280 to 320 K, whereas CHO‑amines decrease by only about one order over the same range. Together, these results demonstrate that OH‑ and CHO‑amines effectively accelerate sulfate‑based NPF through favorable kinetics in humid environments.