To investigate the effects of different structural parameters in the degradation of o -Dichlorobenzene (o -DCB) by dielectric barrier discharge nonthermal plasma (DBD-NTP) and to explore the optimal reactor structural parameters, experimental investigations were carried out using plasma reactors of different structures. The effects of single and double dielectric, different high-voltage electrode positions, different dielectric thicknesses, different discharge gaps and different discharge lengths on the degradation efficiency, carbon monoxide and carbon dioxide selectivity, carbon balance, and ozone of o -DCB were investigated in the reactor. The results show that single dielectric, external high-voltage electrode and lower dielectric thickness, discharge gap, and longer discharge length favor ozone control and improve o -DCB degradation and carbon monoxide CO2 selectivity as well as carbon balance. [ABSTRACT FROM AUTHOR]