Long-chain alkanes are a type of intermediate volatility organic compound (IVOC) in the atmosphere and a potential source of secondary organic aerosols (SOAs). C 12 −C 14 nalkylcyclohexanes are important compositions of IVOCs, with considerable concentrations and emission rates. The reaction rate constants and SOA formation of the reactions of C 12 −C 14 nalkylcyclohexanes with Cl atoms were investigated in the present study. The reaction rate constants of the long-chain alkanes obtained via the relative-rate method at 298 ± 0.2 K (in units of ×10 −10 cm 3 molecule −1 s −1 ) were as follows: k hexylcyclohexane = 5.11 ± 0.28, k heptylcyclohexane = 5.56 ± 0.30, and k octylcyclohexane = 5.74 ± 0.31. The gas-phase products of the reactions were identified as mainly small molecules of aldehydes, ketones, and acids. The particlephase products were mostly monomers and oligomers, but there were still trimers even under high-NO x conditions. Moreover, under high-NO x conditions (urban atmosphere), the SOA yields of hexylcyclohexane are higher than that under low-NO x conditions (remote atmosphere), indicating that more attention should be given to the SOA formation of Cl-initiated n-alkylcyclohexane oxidations in polluted regions. This research can further clarify the oxidation processes and SOA formation of n-alkylcyclohexanes in the atmosphere.

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