Abstract: An electrostatic air cleaner may include a corona charging stage, a precipitation stage, and an air mover (fan). The corona charging stage may include a first and second array placed under electrical potential difference capable of generating a corona discharge. The first array may be substantially parallel corona wires and may be located downstream of an air penetrable second array. The precipitation stage may be downstream from the corona charging stage. The spacing between the first array and the second array may be less than the distance of the precipitation stage to the second array. The air mover may be upstream of the corona charging stage or downstream of the precipitation stage or between these stages. The arrangement allows for higher ion output downstream of the first array with the same voltage and power consumption resulting in greater particle charging and better air cleaning efficiency.