Corona discharge is applied to various fields. In these application fields, changes in the corona discharge characteristics due to atmospheric conditions is often a problem. The effects of airflow and isopar™ G (which is a mixture of several kinds of iso-paraffin: nonane, decane, etc.) vapor on corona discharge are investigated. The voltage required in order to maintain the corona current constant was found to decrease when airflow is applied to the corona discharge area, and the voltage was found to increase when the airflow contains isopar™ vapor. In addition, we found that the accumulation of polymer containing C and O occurs on corona wire when the wire is negatively charged and the airflow contains isopar™ vapor. The initial mechanism of the accumulation is proposed to be due to isopar™ ionization by electron collision to form positive ions, after which, the isopar™ attracted to the wire surface is polymerized at the surface.