Particulate matter (PM) from diesel vehicles is harmful to humans and should be removed from the exhaust gases before its emission into the atmosphere. Plasma PM oxidation is an advanced method to be used for oxidative PM removal. Factors influencing plasma PM oxidation include gas temperature, gas composition, PM amount, the geometry of plasma reactors. The PM oxidation in atmospheric air discharges was carried out using a pulsed dielectric barrier discharge reactor at temperatures of 100, 150, and 200 A degrees C. It was found that PM is oxidized to CO and CO2. CO2/CO concentration ratio is a function of PM amount in the discharge space. PM removal efficiency (PM amount oxidized per kWh energy injection) increased with increasing air temperature and PM amount in the discharge space. Water promotes PM oxidation, which suggested that oxygen atoms produced in the discharge space react with water to yield hydroxyl free radicals that are of more reactivity than oxygen atoms. The activation energy of plasma PM oxidation was kinetically calculated to be 15.4 kJ/mol.