Kinetics and products of the gas-phase reactions of acenaphthylene with hydroxyl radicals, nitrate radicals and ozone

A series of simulation chamber experiments has been performed on the gas-phase atmospheric oxidation of acenaphthylene with the hydroxyl (OH) radical, ozone (O₃) and the nitrate (NO₃) radical. Using a relative rate technique the following rate coefficients (in cm³molecule^-1s^-1) were determined at (293±3) K in 1atm of purified air: (1.09±0.07)×10^-10, (3.99±0.15)×10^-16 and (4.42±0.32)×10^-12 for the reactions with OH, O₃ and NO₃ respectively. The results indicate that all three oxidants effectively contribute to the removal of acenaphthylene from the atmosphere. A denuder-filter sampling system coupled with off-line analysis by gas chromatography - mass spectrometry (GC-MS) was used to determine the gas- and particle-phase products of these reactions. The major products identified in the reaction with OH were naphthalene-1,8-dicarbaldehyde, 1,8-naphthalic anhydride and a 10 carbon ring-opened dialdehyde. The products identified in the reaction with NO₃ and O₃ were predominantly oxygenated compounds arising from reaction at the CC bond in the cylcopenta-fused ring of acenaphthylene. The formation of hydroxylated and nitro-PAHs appears to be a very minor reaction pathway. Acenaphthenequinone, a compound known to generate reactive oxygen species at the cellular level, was formed from the reactions of acenaphthylene with OH and NO₃. The majority of the oxidation products were found to be distributed between the gas and particle phases, with only acenaphthylenol and oxaacenaphthylen-2-one, relatively more abundant in the particle phase. •Reactions with OH, O₃ and NO₃ all contribute to the atmospheric removal of acenaphthylene.•Atmospheric oxidation products are mainly ring-retaining compounds.•The formation of hydroxylated and nitro-PAHs is only a minor reaction pathways.•Addition to the CC bond is the major reaction pathway for NO₃ and O₃ reactions.•Acenaphthylene oxidation products are detected in both gas- and particle-phases.