Coronavirus: can an air purifier protect you?

Coronavirus: can an air purifier protect you?

While there's some evidence air purifiers can reduce traces of airborne viruses, research is ongoing, and you shouldn't rely on one to protect you from Covid-19.

At the start of the pandemic, worried people were - understandably - looking for products to reduce the risk of getting Covid-19, and we saw a spike in online traffic for air purifiers.
Nearly two years on and concerns about contracting the virus have dropped considerably. This is largely thanks to a successful vaccination programme that's provided higher protection from serious symptoms, and a greater understanding of the virus itself.
All the same, nobody wants to be unwell if they can avoid it, and avoiding contracting the virus will still be important to many.
But while recent studies have indicated that air purifiers can reduce traces of airborne viruses such as Covid-19, the advice we gave two years ago remains the same: you shouldn't solely rely on an air purifier to filter out coronavirus in your home. Ventilation and good hygiene practices (such as frequent hand washing) remain the most effective ways to protect yourself.
What we do know is that air purifiers can potentially help improve your air quality in other ways. Read on to find out more about the latest research on coronavirus and air purifiers, plus free ways you can breathe cleaner air at home.

Air purifiers for coronavirus: what do manufacturers say?

At the start of the pandemic, some air purifier manufacturers implied, or outright claimed, that their machines would protect you from coronavirus. Many have since tweaked their messaging, but in some cases it can still be quite unclear and leave consumers uncertain about the benefits (or not) of air purifiers in relation to Covid-19.
For example, some will state that air filtration can remove SARS-CoV-2 (the virus that causes Covid-19), but caveat that with the message that your primary line of defence against getting infected is to maintain social distancing, wash your hands and wear a mask.
Others will say an air purifier can remove coronaviruses from the air, but refrain from explicitly stating that their machines can remove the coronavirus that causes Covid-19.
Here's what popular air purifier brands state on their websites.
AllerAir?- states that 'AllerAir Air Purifiers uses its proprietary Super HEPA filter technology to effectively filter viruses like the Coronavirus COVID-19 which is 0.125 micron in size'. Note the use of the word 'like'. AllerAir is not categorically saying its air purifiers filter out the Covid-19 coronavirus.
Airpura?- states that 'your primary line of defense against getting infected with Covid-19 is to maintain social distancing whenever possible, washing your hands regularly and wearing a mask. According to medical experts, along with the above three essential habits, one should include using an air purifier as an “essential” to ward off concerns about aerosol transmissions'.
Blueair?- states that while its HealthProtect 7400 air purifier can remove coronavirus particles from the air, it is 'not proven to kill SARS-CoV-2 or prevent transmission of COVID-19. Other Blueair air purifiers have not been tested against SARS-CoV-2.
Philips?- states that 'an air purifier by itself does not protect against Covid-19 but can be part of a plan to protect yourself and your family by improving ventilation and having clean air'.

What does the science say about air purifiers for Covid-19?

At the start of the pandemic, there was - as you'd expect - little to no evidence about the efficacy of air purifiers against Covid-19.
As you'd also expect, there has since been research carried out to investigate just this matter.
In November 2021, a research team at Addenbrooke's Hospital and the University of Cambridge reported that they were able to use HEPA filter/UV steriliser air purifiers to remove most airborne traces of SARS-CoV-2 on surge wards at the hospital. The air purifiers also successfully filtered out other bacterial, fungal and viral bioaerosols (airborne particles containing living organisms). However, it's worth noting they used a HEPA 14 filter (which is medical grade) in the air purifiers, rather than HEPA 13 filters, which are more commonly used in consumer appliances.
And a July 2021 report from the Centre for Disease Control (CDC) in the US also suggested that portable HEPA air cleaners could reduce exposure to SARS-CoV-2 aerosols indoors. However, it focuses on conference rooms, not household environments, and used a simulated environment.
In short, there's a lot more real-world evidence needed - and the results of these research studies don't change our advice about air purifiers and Covid.