Abstract: An arrangement for cleaning ventilation air coming from a paint spray booth and polluted with paint particles is provided with a liquid flow for separating part of the paint particles from the ventilation air and a wet electrostatic precipitator for separating any remaining paint particles and liquid droplets from the ventilation air. The electrostatic precipitator is located in an enclosure underneath the floor of the spray booth, with a surface of the enclosure being poured over with the liquid flow to remove part of the paint particles. The enclosure is further designed so that the ventilation air from the spray booth is caused to be deflected through an angle of 10.degree.-170.degree. in relation to the substantially vertical direction of flow through the spray booth before passing through the liquid flow and into the electrostatic precipitator.