I know that every electric motor produces some ozone, it's unavoidable. Most of the time I don't notice it. We had a Honeywell HEPA room air purifier (basically a fan which pulls in room air through a carbon prefilter and a nested HEPA filter, traps most dust and pollen) in the kids' room for years with no problem, changing filters as necessary, but last year the room started smelling more and more like ozone whenever the purifier was on. Finally it got to the point where I'd start coughing as soon as I stepped into the room.

Hoping that it was just a motor going bad, we bought two more air purifiers, from different stores -- and both of them started producing an ozone smell after a day also.

Fortunately my kids aren't suffering from allergies currently so we've just turned it off.

Any ideas what's going on?

1 Answer 1


Pretty sure most purifiers work by creating ozone, so I don't think you can really avoid it. There may be some type that just pull air through a filter vs doing the thing where it uses ozone to zap the dust or whatever.

  • 2
    Ozone doesn't purify the air. Ozone at surface level is a pollutant; it irritates the lungs and nasal passages.
    – Snowbody
    Jun 26, 2014 at 20:25
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    If you are using the ionizer type, those produce ozone. There are also many types that are specifically ozone producing, but generally the EPA has been cracking down on those. One that is just a hepa filter without any ionizing shouldn't be producing ozone. The ceramic thermodynamic type also shouldn't generate any ozone. If you look at the wiki for 'air purifier' it covers the various different types available and specifies which ones create ozone. Realistically air purifiers aren't necessary and it's debatable if they even help.
    – Zach
    Jun 26, 2014 at 20:36
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    I specifed HEPA type in the original question; I clarified that it is just a filter.
    – Snowbody
    Jun 26, 2014 at 20:37
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    HEPA is a specification of the filter, it can still have an ionizing unit or something similar. Are you sure it's ozone you're smelling? Does it go away completely when you turn the unit off?
    – Zach
    Jun 26, 2014 at 20:41
  • Not completely sure it's ozone. I can smell it coming out of the air purifier's vent. When you turn it off the smell doesn't increase, and by ventilating the room the smell goes away. Obviously that's not a good solution if there's a high pollen count.
    – Snowbody
    Jun 26, 2014 at 22:31

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