Yes, the Dyson Air Purifier has a certification that indicates it is ozone-free.  This certification is the UL 2998 standard, an Environmental Claim Validation Procedure (ECVP) specifically for Zero Ozone Emissions from Air Cleaners.  Dyson purifiers achieve this by not using ionization to purify the air, and as a result, they do not generate ozone. (1.)(2.)