The piezoelectric direct discharge sustained using a high-performance piezoelectric transformer (PT) with a voltage transformation ratio of >1,000 was used for the generation of an atmospheric pressure plasma jet (APPJ). The ionization gases used are ambient air and compressed dry air. The APPJ was characterized using capacitive probe measurement, ozone concentration measurement, and activation area determination. The activation experiments were conducted on a highdensity polyethylene. The activation area was visualized using pure formamide test ink (58 mN/m) and captured by a digital camera. The influence of gas flow, PT power, and the distance between the PT and the substrate were investigated. K E Y W O R D S atmospheric pressure plasma jet (APPJ), CeraPlas™ F, piezoelectric direct discharge (PDD), piezoelectric transformer (PT), plasma surface treatment This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.