The phenol degradation processes by pulsed corona discharges are investigat
ed under three kinds of discharge atmosphere lair, argon and oxygen). The t
emporal variations of the concentrations of phenol and the intermediate pro
ducts are monitored by LIF spectroscopy. The species of the intermediate pr
oducts are identified by spectral analysis. It is clarified that the oxidat
ive gaseous reagents produced from O-2 and those from H2O degrade phenol to
intermediate products with comparable degradation rates. The degradation v
ia the reagents from H2O gives rise to the formation of molecules exhibitin
g fluorescence at 400-500 MI, in addition to dihydroxybenzene (DHB), while
the degradation via the reagents from O-2 produces only DHB. The reagents f
rom O-2 play an important role in the conversion of phenol to DHB.