Do air purifiers add harmful ozone to your home?

It’s one of the most common questions we’ve been asked lately by both new and existing customers. And honestly? We’re glad people are asking. It shows that awareness around indoor air quality is growing, and that’s a great thing.

To help clear up the confusion, here’s a simple, honest guide to understanding ozone—and whether air purifiers contribute to it inside your home.

What Is Ozone?

Ozone (O₃) is a highly reactive form of oxygen. It can occur both naturally and through man-made processes. While it's colourless, ozone has a distinctive, sharp odour similar to chlorine.

Is Ozone Good or Bad?

It depends on where it is.

  • High in the atmosphere: Ozone forms a protective layer that shields the Earth from harmful ultraviolet (UV) rays. In this context, ozone is essential.
  • At ground level: Ozone becomes a pollutant. In high concentrations, it can cause serious respiratory issues. Even at lower indoor levels, prolonged exposure may be harmful especially for individuals with conditions such as asthma, COPD, bronchitis, or emphysema.

What Causes Ground-Level Ozone?

Outdoors, ground-level ozone is typically caused by car exhaust fumes and certain industrial activities.

Indoors, it enters our homes through open windows, doors, and ventilation. But there are also hidden contributors inside the home, including:

  • Printers and photocopiers
  • Hairdryers
  • Some types of air purifiers

Yes, you read that right. Certain air purifiers can add ozone to the air.

Do All Air Purifiers Emit Ozone?

No but many do, at least to some extent.

Some air purifiers are marketed as “ozone generators,” with claims that ozone can neutralise viruses, bacteria, mould, and volatile organic compounds (VOCs). While there’s some truth in these claims, here’s the catch: for ozone to be effective in this way, it needs to be present in quantities far above what is safe to breathe.


That’s why organisations like the EPA (Environmental Protection Agency) and the California Air Resources Board (CARB) strongly advise against using ozone generators in occupied spaces.

So How Can You Be Sure Your Air Purifier Is Safe?

Unfortunately, in the UK there are currently no laws that prevent manufacturers from selling ozone-emitting air purifiers. That means the responsibility falls on you, the buyer, to choose wisely.

Here’s how to protect yourself:

  • Avoid ozone generators – If a purifier is marketed as an ozone generator, don’t use it indoors.
  • Look for CARB certification – The California Air Resources Board has the strictest ozone emission standards in the world. Products that meet their standards are safe for home use.
  • Ask the retailer – If it’s not clearly stated on the product, contact the retailer or manufacturer. Reputable sellers will know the answer.
  • Don’t be fooled by price – A high price doesn’t necessarily mean low ozone. Some well-known brands sell purifiers with little transparency around emissions.

Which Air Purifiers Are the Safest?

Due to the lack of transparent testing by many brands, we can’t give a definitive list of every safe air purifier on the market. What we can say is this:

Every air purifier we sell on our website has been independently tested and certified to meet or exceed the world’s strictest ozone emission standards.

That means you can shop with complete confidence, knowing your air purifier is truly helping, not harming, your indoor air quality.

In Summary

Do air purifiers add harmful ozone to your home?

The honest answer: Many do. Some don’t. The key is knowing which is which and that’s where we’re here to help.

If you’d like expert guidance on choosing an air purifier that’s both effective and ozone-safe, just give us a call on 01207 507444. We’ll be happy to point you in the right direction.

Clean air starts with smart choices.

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