Absolute rate constants of secondary steps in the hydroxyl-initiated degradation of aromatics. Fate of the adducts in the presence of O2 and NOX

Additon of OH, k2, is the main atmospheric reaction path of aromatics. The abstraction channel, k1, contributes less than 10 per cent for most aromatics. The formation of the adduct is reversible, hence further reactions of the adduct, k add/scav, are required to remove the aromatic pollutant from the atmosphere. The adduct reactions with NO2 as scavenger are fast, whereas those with O2 are slow, but dominating in the atmosphere. Since the O2-reaction of phenol-OH is about 100 times faster than those of benzene-OH and toluene-OH, we studied two further aromatics, p-xylene and m-cresol, for comparison.