This paper reports aerosol formation from styrene removal with an AC/DC streamer corona plasma system in air. Aerosol formation from ozone-induced styrene removal is also investigated to further understand the aerosol formation process, and aerosol number concentration and size distribution inside the plasma system. For ozone-induced styrene removal, aerosols show a bi-modal-like size distribution. However, for non-thermal plasma induced styrene removal, aerosols show a mono-modal-like size distribution due to electrostatic force between charged aerosols. The total number concentration of these non-thermal plasma aerosols is around 1 x 10(6) cm(-3) with diameters between 28 and 157 nm. The non-thermal plasma induced both polymerization and oxidation processes contribute to the aerosol formation. Aerosol carbons are about 61% of C-C and/or C-H, 22% of C-O-C and/or C OH, 15% of C=O, H-C=O and/or aromatic-OH, and 2% of COOH and/or COOR related compounds. The non-thermal plasma can be used not only for styrene removal, but also for by-product aerosol collection. (C) 2013 Elsevier B.V. All rights reserved.