The first ozone generator
The first ozone generator "Corona ozone generator" was patented in June 1896 by Nikola Tesla
Only four years later, Nikola Tesla founded the Tesla Ozone Company, which produced ozone generators for a variety of purposes - sterilization of the hospital rooms, instruments, drinking water sterilization, wound cleaning, therapeutic and medical uses, as well as ozone-based products.
Carlson W. Bernard and Tesla: The Electrical Age Inventor. Princeton University Press. ISBN 978-1-4008-4655-9.