Mechanism and thermal rate constant for the atmospheric oxidation of coumarin in the atmosphere

[Display omitted] •The process of the atmospheric degradation of coumarin initiated by OH radical was investigated in the presence of O2 and NOx in this work.•Compared to the H abstractions by OH radical, the reactions of OH addition to coumarin are the dominant processes.•The products for OH initiated atmospheric oxidation of coumarin include hydroxy coumarin, ketones, quinones, dialdehyde and epoxies.•The overall rate constant of the reaction of OH and coumarin is 6.17 × 10-10 cm3·molecule-1·s−1 at 298 K and 1 atm.•The atmospheric lifetime of coumarin by OH radicals is about 0.450 h. The process of the atmospheric degradation of coumarin initiated by OH radical was investigated in the presence of O2 and NOx in this work. Compared to the H abstractions by OH radical, the reactions of OH addition to coumarin are the dominant processes. The products for OH initiated atmospheric oxidation of coumarin include hydroxy coumarin, ketones, quinones, dialdehyde and epoxies. The overall rate constant of the reaction of OH and coumarin is 6.17 × 10-10 cm3·molecule−1·s−1 at 298 K and 1 atm. The atmospheric lifetime of coumarin by OH radicals is about 0.450 h.