A dielectric barrier discharge (DBD) reactor was fabricated and operated in two steps. In the first step (oil mist collection) oil mist aerosols were collected and in the second step (oil mist-to-gas conversion), without supplying oil mist particles but with supplying only clean air flow, collected oil mist particles were converted to gas species. An aerodynamic particle sizer, a scanning mobility particle sizer system, and a real-time gas analyzer were used to measure particle and gas concentrations at the inlet and outlet of the DBD reactor. The oil mist collection efficiency decreased from 78% to 21% but the oil mist-to-gas conversion efficiency increased from 6% to 95%, with increasing frequency from 1 kHz to 10 kHz. Low frequency caused higher amplitude of oscillating particle movement between the electrodes, resulting in higher collection efficiency. At a higher frequency, more electrons were generated, which resulted in the formation of more reactive oxygen species and thus increased subsequent oxidation. Increased surface temperature of the DBD reactor with higher frequency also contributed to higher oil mist-to-gas conversion efficiency. The DBD reactor can be applied to reduce oil mists generated in metal working and cooking processes. (C) 2015 Elsevier B.V. All rights reserved.