I put mine on my back entrance which is basically open air. Close door with cord under it. Able to plug it in without being able to see it and ozone spews out t

I put mine on my back entrance which is basically open air. Close door with cord under it. Able to plug it in without being able to see it and ozone spews out to pollute my city even more.. Do you know how long of an exposure is needed to be effective? assuming within 2-3 feet but single source not even light