Photochemical reaction of 2-chlorobiphenyl with N(III) (H2ONO+/HONO/NO2−) in acidic environment studied by using co-linear laser flash photolysis

• The photochemical conversion of 2-PCB in the presence of N(III) is initiated by OH oxidation.
• The second-order rate constant for reaction of 2-PCB with OH is (8.9 ± 1.2) × 109 M−1 s−1.
• Only HONO and NO2− are the forms of N(III) important to pollutant photochemical transformation.

Photo-induced transformation in the presence of N(III) is an important pathway for pollutants conversion in atmospheric condensed phase. In this study, the photochemical reaction between 2-chlorobiphenyl and N(III) was investigated in acidic environment by using co-linear laser flash photolysis technique. The photo-induced conversion of 2-PCB is initiated from its rapid oxidation by OH, a primary product from the photolysis of N(III). The second-order rate constant for the reaction between 2-PCB and OH was determined to be (8.9 ± 1.2) × 109 M−1 s−1. HONO and NO2− were found to be more important than H2ONO+ with respect to the photochemical transformation of pollutants in atmospheric hydrometeors. The complicated photochemical conversion pathways and their significance in the atmosphere were discussed as well in this paper.