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Coronavirus: can an air purifier protect you?

Which? separates truth from wishful thinking to explain why an air purifier can’t be relied on to protect you from coronavirus

Coronavirus: can an air purifier protect you?

We’ve seen a spike in online traffic for air purifiers recently, as worried people are, understandably, looking for products to help prevent getting coronavirus. 

Read on to find out why an air purifier isn’t the solution, but how it can help with air quality in other ways.

Plus, discover the ways in which you can improve your indoor air quality now that you’re spending more time at home.


Just want to see which air purifiers that impressed in our tests? See our list of Best Buy air purifiers.

You can also keep up to date on our latest coverage of the pandemic over on our coronavirus advice hub.


Air purifiers for coronavirus: do they exist?

Some air purifier manufacturers are implying, or outright claiming, that their machines will protect you from coronavirus.

Examples of manufacturers making direct claims about this include AllerAir (below, spotted on 25 March)

And Airpura, spotted on 24 March:

By 25 March, the Airpura website had been adjusted to say ‘how an air purifier can kill airborne viruses’ rather than ‘how an air purifier can kill airborne viruses, such as coronavirus’.

These manufacturers only ship to the US and Canada, so their products aren’t available on the UK. And you could argue that, even if these products don’t work as well as claimed, there’s no harm in buying one. But there is a risk that such advertising gives false hope and could act as a distraction from official government advice.

Blueair air purifiers

You may also have seen the following claims on the website of Blueair – an air purifier brand which is popular in the UK. It says:

‘Blueair air purifiers have not been tested for the removal of coronavirus yet, as it’s a new strain that was discovered in 2019.

‘However, here is what we do know: Blueair air purifiers have been third-party tested for the removal of the most common viruses and bacteria with a clearance rate of over 99.99%. The tests included H1N1 influenza, staphylococcus aureus, E coli and aspergillus.

‘Blueair’s HEPASilent™ technology captures at least 99.97% of airborne particles down to 0.1 microns in size. This includes any viruses with a particle size of at least 0.1 micron. Corona viruses measure about 0.12 micron.’ 

Blueair air purifiers are highly rated by Which?, but we are in no way is saying that these products (or any commercial air purifiers) protect you from coronavirus.

We reached out to Blueair for comment. Blueair told us that:

‘We have made it absolutely clear on our website that an air purifier will not protect you from coronavirus. We have also stated very clearly that Blueair has not tested against the new coronavirus. We have posted the information you refer to on our website in response to the many questions (including questions about particle sizes) that have been flooding in from all over the world – from consumers, hospitals and media – asking specifically about air purifiers and coronavirus.’

Air purifiers and particle filtration

Coronavirus particles do fall within the particle-size range that HEPA filters, found in some air purifiers, capture, which is 0.01 micron and larger. 

Theoretically, an air purifier could have the capability to capture coronavirus, if the purifier had a particular type of HEPA filter with an efficiency of 99.95% and an ultra violet lamp to then kill coronavirus.

Crucially, though, none of this has been scientifically proven yet, and, in the real world, a lot depends on factors such as:

  • the type of HEPA filter you have
  • the size of your room
  • the number of air changes in that room
  • the state of the filter
  • whether your air purifier is a bit old and so has a fading UV lamp. 

Also, the World Health Organization (WHO) states that ‘studies to date suggest that the virus that causes COVID-19 is mainly transmitted through contact with respiratory droplets rather than through the air’.

Air purifier manufacturer Meaco told us: ‘An air purifier can help in maintaining your general wellbeing, which can only be a positive to try and stay safe from COVID-19. But, given air purifiers have not yet been tested with COVID-19, we would not want anyone to think that an air purifier could save them from COVID-19 and everyone should concentrate on the NHS/government advice first and foremost.’ 

So we’ll need to await further scientific study before we can say whether an air purifier is a worthwhile investment at such a time.

How to stay safe otherwise

Here’s how you should protect yourself instead, according to official government advice:

  • Wash your hands frequently
  • Catch coughs and sneezes in a tissue
  • Do not touch your eyes, nose or mouth if your hands are not clean
  • Only leave the house for one of four reasons: 1) Shopping for basic necessities (food and medicine). 2) One form of exercise a day, alone or with members of your household. 3) Medical need, or to provide care or to help a vulnerable person. 4) Travelling to and from work, but only where this absolutely can’t be done from home. Maintain a distance of at least two metres from others. 

How an air purifier can help you improve your indoor air quality

An air purifier could potentially help you in other ways, especially now all of us are spending a lot more time indoors.

If you suffer from allergies, for example, a good air purifier can help you by trapping pollutants such as dust and pollen particles.

Some air purifiers come with carbon filters, designed to also capture gases.

We know many people are also interested in using air purifiers to tackle traffic pollution. Yet it’s currently impossible to say which are most effective at tackling gases caused by traffic pollution coming in through an open window. So air purifiers aren’t a perfect or complete solution to the problem of air pollution.

However, you can use our air purifier reviews to find one that does a great job of trapping dust, pollen and smoke particles at least.

What should I look for in an air purifier?

If you are going to buy an air purifier, some come with features that make them easier to use. These include smart features, which let you control the air purifier from your smartphone and/or check pollution levels in your home, and auto settings, which prompt the air purifier to spring into action when a pollution levels rise (you’ve just sprayed deodorant, say).

The fact that an air purifier has lots of features doesn’t mean it will do a good job, by any means, so it’s important to check our reviews before you buy.

As a minimum, 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.

And make sure to clean and replace any filters according to the manufacturer’s instructions. A clogged-up filter won’t do much, but overly vigorous cleaning can also damage a filter.

How to improve your indoor air quality in quarantine

As of 23 March, the government has placed new restrictions on our movements.

While it’s natural to be more concerned about your indoor air quality, you don’t need to spend a lot of money to make an improvement to it.

Here are some simple steps you can take to breathe cleaner air.

Open a window

You might not be able to go outside, but you can still open your window to get some fresh air. It’s also one of the easiest way to remove polluting particles from your living space. Generally, we recommend being strategic about this and trying to time it for when there isn’t likely to be lots of traffic outside, particularly if you live on a busy road.

Minimise the toiletries you’re using

In the past, we’ve recommended swapping your usual products for a natural alternative, but, unless you’ve got a good supply in reserve, there’s a good chance you’ll run out of your existing toiletries at some point in the next few weeks.

You’ll probably want to keep looking vaguely presentable if you have to take part in video calls with your colleagues, but you may well find yourself using less hairspray, body sprays and so forth now that you’re not socialising.

Use your cooker hood

We’re all going to be doing more home cooking now that we can’t eat out. Switch on your kitchen hood and fans during and after cooking, even if you find them annoyingly noisy, to clear the air of oil and other ingredients that have evaporated into it, and limit damage to your walls and kitchen cabinets.

Head to our guide to improving your indoor air quality at home to find out more.

Reduce the likelihood of pollen triggering an asthma attack

Emma Rubach, head of health advice at Asthma UK, says: ‘Trees have been releasing pollen for several weeks, but the warm spring weather is going to make these pollen levels spike. If you’re already getting symptoms, it’s not too late to help yourself stay well. ‘

Around 3.3 million people with asthma are affected by pollen, which can cause symptoms such as wheezing, a tight chest or coughing.

If that applies to you, Asthma UK says you should:

  • Take your prescribed preventer medicine to soothe your irritated airways, so that you’re less likely to react to the pollen trigger
  • Take hay fever medicines, such as antihistamines, as they stop the allergic reaction that triggers asthma symptoms and keep itchy eyes and runny noses at bay
  • Keep your blue reliever inhaler with you at all times in case of an emergency.

Indoor air quality for people with a lung condition

The British Lung Foundation also offers useful guidance on what people with a lung condition should do to stay safe during the coronavirus pandemic.

Zak Bond, Policy Officer (Air Quality) at the British Lung Foundation, says: ‘There’s never been a more important time for all of us to think about the quality of the air we are breathing within our own homes.

For the 12 million people in the UK living with respiratory condition, such as asthma or chronic obstructive pulmonary disease (COPD), it’s particularly important to minimise exposure to indoor pollutants, which can cause a flare up of their symptoms.

There are some simple steps we can all take to improve indoor air quality such as keeping rooms well-aired by opening windows several time a day and particularly when we are cooking or using the shower. It’s also important to keep the rooms at a comfortable temperature throughout the day to reduce the levels of moisture in the air which can result in mould.

Air purifiers have been found to reduce background concentrations of particulate matter which can trigger symptoms.’

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