Can you use an air purifier for hay fever?

Hay fever symptoms are distracting at best, and painful and disruptive at worst. 

Tree pollen season is the first to arrive, from late March to mid-May, followed by grass pollen (mid-May to July) and weed pollen (June to September).

While there are various steps you can take outdoors to help alleviate symptoms (see our tips below), a decent air purifier could also help you once you get home.

Keep reading to find out how an air purifier could benefit you and the key features to look out for.

Already decided to buy one? Which? members can find out which are the best air purifiers from our comprehensive tests

Can an air purifier help with hay fever symptoms?

An air purifier works by sucking in air, trapping any floating particles and then circulating the clean air back out.

Our lab testing checks how well they can remove pollutants of different particle sizes, which represent common household allergens such as dust and pollen.

A good air purifier will be able to filter out these particles, so may help to alleviate symptoms of hay fever and other allergies while you're indoors.

Even if pollen is your main priority, there's no need to buy a machine that excels at removing small particles from the air but performs poorly in our other tests. There are more than enough that do well in all categories.

Can you get a cheap air purifier?

You could buy an air purifier for less than £100 – or you could spend more than £700.

Those costing less than £100 don't often do well in our tests. That's partly because they tend to be smaller and don't contain a fan that's big enough to draw in much air.

Air purifier features to look out for

• HEPA filter – this stands for high-efficiency particulate air filter. It uses a combination of trapping mechanisms to capture pollutants. EU standards state that, to use the term HEPA, a filter must remove at least 99.95% of tiny particles with a 0.3u03bcm (micron) in diameter. Don't be tempted to buy one with a marketing name such as HEPA-type filter, as it might not meet the same European standards.
• Carbon filter – designed to absorb unpleasant smells and gases. Sometimes called an activated carbon filter or charcoal filter.
• Automatic mode and air-quality sensors – these monitor the air and ramp up purification if pollution levels rise. You'll sometimes also get information on the air quality in your room via a display on the device.
• Timer – useful if you only want to run your air purifier for a set period. Some allow you to set a schedule.
• Smart functionality – enables you to control the air purifier or get information on your air quality via an app on your phone.

Popular air purifiers we've tested

Here are some popular air purifiers, based on the number of visits to our online air purifier reviews over the past six months. 

Remember, 'popular' and 'impressive' can be two different things, so make sure you consult our expert reviews before buying.

Dyson Big+Quiet Formaldehyde BP03

Dyson's latest smart-compatible air purifier weighs a hefty 11.6kg, making it one of the bigger models we've tested.

It's feature-packed and has night and auto modes, a timer, a remote control and 10 fan speeds.

Read our Dyson Big+Quiet Formaldehyde BP03 review to find out how it compares with the other air purifiers we've tested.

Philips PureProtect AC0920/10

You can control this Philips air purifier via an app on your phone, saving you the hassle of getting up to adjust the settings.

It has two fan speeds, night and auto modes, and a child lock on the display panel. Philips says it's suitable for rooms up to 65 square metres.

It's available from Philips (£130).

Read our Philips PureProtect AC0920/10 air purifier review to see if it will be able to clear allergens from your home.

Ikea Starkvind

Ikea's lower-cost air purifier has an auto mode, five fan speeds and a useful carry handle on the back.

You can control the Starkvind via an app on your phone, but you’ll need to buy the Dirigera hub or Tradfri gateway to add it to your home network, which pushes up the overall price.

It's available from Ikea (£144).

Read our Ikea Starkvind review to find out if this budget-friendly model is good at removing particles from the air.

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What else can help with pollen allergies?

Margaret Kelman, Specialist Allergy Nurse at Allergy UK, has the following tips:

• There's evidence to suggest that wearing a mask will help to stop you inhaling pollen particles.
• Wraparound sunglasses or a hat with a peak or large brim will help to keep pollen out of your eyes and face.
• On high-pollen days, shower, wash your hair and change your clothes when you arrive home.
• Keep windows closed. This is most important in the early mornings when pollen is being released, and in the evening when the air cools.
• Avoid mowing lawns or raking leaves yourself if possible.
• Avoid drying clothes/bed linen outside when pollen counts are high.
• Wipe down pets with a damp cloth to remove any pollen they may have brought in with them.

It's also a good idea to download the Met Office weather app to stay up to date on daily pollen levels.

If you also need medication to help with symptoms, take a look at hay fever symptoms and treatments compared

How Which? tests air purifiers

We measure the clean air delivery rate (CADR) of each machine, which looks at how quickly it can remove polluting particles from the air.

Our testing answers the following key questions:

• How swiftly does each air purifier trap common allergens at a range of particle sizes?
• How good is the air purifier at removing odours and gas pollutants from the air?
• How well do the filters keep working as they age?
• How noisy is it on full and low power?
• How much energy does it use?
• Are the filters easy to remove and replace?

Best Buy air purifiers will do a great job, while the worst are terrible at removing particles and gas pollutants, are noisy and are difficult to use.