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.
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.
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.
Coronavirus particles do fall within the particle-size range (0.01 microns and larger) that HEPA filters, found in some air purifiers, capture.
An air purifier could therefore capture coronavirus if the device had a particular type of HEPA filter, with an efficiency of 99.95%, and an ultra violet (UV) lamp to then kill coronavirus.
Crucially, though, in the real world, a lot depends on factors such as:
There is increasing evidence to show that Covid-19 can linger in enclosed spaces and that ventilation is key.
Ventilation is the process of replacing shared, staler air with fresh air from outside. The more ventilated an area is, the more fresh air there is to breathe and the less likely a person is to inhale infectious particles.
The government recommends:
The government's advice also recommends that if someone in your home is self-isolating, you should open a window in their room and keep the door to the room closed to reduce the spread of contaminated air to other parts of the household.
Covid-19 can be transmitted through respiratory droplets when you're in close proximity to someone, and by touching contaminated surfaces.
You can also:
When it comes to staying healthy generally, regardless of Covid-19, breathing cleaner air can only ever be a good thing.
If you can increase the flow of fresh air into your home by opening windows, do that. But if that's not a practical option - say, you live on a very polluted street or you suffer from hay fever - then an air purifier can help create cleaner air.
If you suffer from allergies, for example, a good air purifier can trap pollutants such as dust and pollen particles.
If you're going to buy an air purifier, look for one with a HEPA filter. Other filters - including ones with names such as HEPA-type filter - aren't held to the same European Standards as HEPA filters.
Some purifiers come with features that make them easier to use. These may include, for example: