Ozone production from photocopying machines

Ten photocopying machines of different makes and models were tested for ozone emissions. All but one produced detectable amounts. Concentrations at operator's breathing zone varied from less than 4 to 300 micrograms/m3, which corresponded to emission rates of less than 1 to 54 micrograms/copy. Servicing reduced emissions to less than 1.4 micrograms/copy, but preservicing levels were retained after several weeks of operation.