Best air purifiers for allergies 2024: Tried and tested | Live Science

We have tried and tested the best air purifiers for allergies to help shield your home from pollen, pet dander, dust and other airborne allergens ― these are our top picks to look for ahead of Black Friday.

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Autumn is a great time to invest in one of the best air purifiers for allergies. With the hay fever season being long gone, it is easy to snap one up at a discounted price — and even more so in the run-up to Black Friday sales. But which appliance should you choose?

Not every one of the best air purifiers is capable of trapping tiny airborne allergens. If hay fever and pet allergies are your main concerns, you want to look for an appliance that can handle such a feat. Most importantly, your air purifier should be equipped with a High Efficiency Particulate Absorbing (HEPA) filter. "These filters can remove up to 99.97% of small airborne particles, including dust, pollen, and mold spores," Dr. John McKeon, the CEO of Allergy Standards and a principal at the Indoor Air Innovation & Research Institute, told Live Science.

You may also want an appliance with extra filters, such as the Levoit Vital 200S or the Rabbit Air A3, or an air purifier that can monitor air quality — like the Molekule Air Pro, for example.

The best air purifiers for allergies can bring relief to your symptoms if you suffer from allergies to airborne particulates, such as grass pollen, dust mite allergens and pet dander. However, they do not affect humidity levels. If you are concerned about mold and condensation, consider investing in one of the best dehumidifiers. For more information on the efficacy of air purifiers, scroll down to our Air purifiers for allergies FAQs section.

Each air purifier in this guide was tested by our expert team and according to the same testing protocol. We looked into the design, features, ease of use and functionality of the models, and used an industry-grade air particle monitor to assess their performance. Scroll down to the How we test section for more details.

Here are our top picks of the best air purifiers in a ‘quick view’ layout. For more detailed reviews of each air purifier, scroll down and click through to our reviews.

Best overall

Best overall

The Levoit Core 600S comes out on top with its inconspicuous design, impressive performance and handy smart features — and it is reasonably priced, too.

Read more below

Best budget option

Best budget option

This air purifier packs a lot of value into its $99 price tag — it is compact, sleek and does not compromise on performance. Great option for tight spaces.

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Best aesthetics

Best aesthetics

It will be a talking point in your home — ultra-quiet and immensely powerful, this air purifier comes with customizable filters and an impressive range of unique designs.

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Best for monitoring air quality

Best for monitoring air quality

The medically-graded Molekule Air Pro offers some of the most detailed air quality readings you can find in an air purifier, and its air-cleaning capabilities are hard to match.

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Best air purifier with humidifier

Best air purifier with humidifier

The Turonic PH950 air purifier will keep the indoor air clean and moisturized making it easier for you to breathe. It is quite a big and bulky appliance, but it delivers in the looks department.

Read more below

Best for homes with pets

Best for pet owners

This smart air purifier does a great job of trapping pet dander and unpleasant smells, without generating loads of noise or requiring heavy maintenance.

Read more below

Why you can trust Live Science Our expert reviewers spend hours testing and comparing products and services so you can choose the best ones for you. Find out more about how we test.

Our expert review:

✅ You want excellent air-cleaning performance: It features a three-stage filtration system.

✅ You want smart features: This air purifier features an app that allows you to control it from your phone.

✅ You are looking for a bedroom air purifier: While it's not silent, we appreciated how quiet this air purifier was, even when not in sleep mode.

❌ You are short on space: It's a relatively big and bulky unit.

❌ You're on a budget: It is not too expensive, but there are certainly more affordable models in this guide.

🔎 Levoit Core 600S: It may not be the most compact or good-looking air purifier on the market, but it offers exceptional air-cleaning performance, plenty of smart features and user-friendly design — and it does not cost the earth. ★★★★½

The Levoit 600S is our top choice for an air purifier that effectively captures allergens in your home, and with good reason. Not only did it perform well in all of our tests during our full Levoit Core 600S review, but it's also easy to use and packed with handy smart features.

Thanks to its True HEPA H13 and advanced activated carbon filters, this air purifier aced our tests under a number of conditions, removing as much as 99.9% of particles smaller than 0.3 microns at certain times. It is quiet, too. When we measured its noise levels with a decibel-counting app, we did not note more than 55dB, which is quieter than an average refrigerator.

Not only is the Levoit 600S a powerful air purifier, but it also gains points for its discreet design — the toned-up colors and traditional rectangular shape make it easily blend with most home decors.

We found that setting up the air purifier is easy thanks to the intuitive controls, and there's plenty of information accessible on the app connected to your purifier, which gives you statistics on historical and current air quality within your home, which we thought was a great feature.

On the other hand, the Levoit 600S is quite a bulky machine, so it may not be suitable for tight spaces. It is also relatively expensive so might not be ideal if you're on a budget — but that said, it's still more affordable than some of the Dyson and RabbitAir models, for example.

Our expert review:

✅ You don't want anything complicated: It's easy to use and ready to go right out of the box.

✅ You don't have a lot of room: It stands 22 inches tall and around 10 inches wide, so it's good for slotting into a narrow space.

❌ You want something that blends in: While we wouldn't consider it to be ugly, it may not blend in with your interiors.

❌ You want smart features: For that, you may need to invest in a more premium air purifier.

🔎 GermGuardian AC4825E: It is compact, easy to use and sleek-looking, but more importantly, this budget-friendly air purifier does a great job of trapping airborne allergens. It does not have any smart features, though. ★★★★

If you’re on a budget and need an air purifier to tackle your allergy symptoms, then the GermGuardian AC4825E will be an inexpensive purchase that can go a long way to help you breathe more easily.

Complete with a HEPA filter and a charcoal filter to filter odors, this appliance can make your living space a nicer place to be. It’s also ultra-quiet, meaning it can work away in the background without distracting you from whatever you're doing.

As you might expect with a smaller unit, the coverage of this air purifier is not quite as extensive as bulkier models. It would be suitable for single rooms, rather than expansive spaces, and stands at just 22 inches tall, meaning it won’t be too disruptive to your room’s decor, although it's not quite sleek enough to blend in.

There are some other handy features too, including a light to indicate a filter change is due and three speeds including an ultra-quiet sleep mode so that you can keep your machine running into the night.

We were impressed by its ability to remove harmful particles in our match and incense tests during our full GermGuardian AC4825E review, especially for its price point. If you want a no-frills, but a very effective air purifier, we’d recommend the GermGuardian.

Our expert review:

✅ You want a real looker: This air purifier comes in multiple eye-pleasing designs.

✅ You need an air purifier for a large bedroom: It boasts powerful performance and it is whisper-quiet.

❌ You are on a budget: It costs between $749.95 and $769.95, and its filter replacements are expensive, too.

❌ You need to move it around a lot: It does not feature any handles or ridges.

🔎 RabbitAir A3: This air purifier will be a talking point in your home. It is beautifully designed, whisper-quiet and exceptionally effective at removing airborne allergens. The caveat? The A3 is relatively expensive. It could be more portable, too. ★★★★

If you are looking for a powerful air purifier with a truly unique design, and you need it to cover larger rooms in your home, then the RabbitAir A3 is the ideal choice for you.

This thoughtfully designed air purifier comes in over 10 colorful designs, and it features a neat mood light that can be automatically switched off at night. More importantly, it boasts excellent air-cleaning performance. Certified Asthma & Allergy Friendly by the Asthma and Allergy Foundation of America, the RabbitAir A3 will easily get rid of pollen, pet dander and many other airborne allergens. And because it is Energy Star Certified, it will not put a strain on your energy bill while doing so.

During our RabbitAir A3 air purifier review, we were thoroughly impressed at its functionality. It is relatively large, but light and compact, and it does not make much noise even when kicked into high gear. Unlike many other air purifiers on the market, the RabbitAir A3 can also be mounted on the wall, making it a great option for households with pets or small children. We also liked its user-friendly display, and that it was easily controlled via a handy app.

Moreover, the RabbitAir A3 features a whopping five filters, one of which can be customized to suit your specific needs. For example, you can choose a Germ Defense filter to trap harmful microbes, or opt for a Pet Allergy filter to clear your air of pet dander.

There are, however, several downsides to the RabbitAir A3. This air purifier is relatively expensive, and its filter replacements come at a steep price tag. It is also tricky to move around, as it does not feature any handles or ridges.

Our expert review:

✅ You want something multifunctional: The Dyson Purifier Cool performs well and doubles as a cooling fan.

✅ You want smart features: You can control it with your voice or through the accompanying app.

❌ You're on a budget: It's one of the most expensive options on this list.

❌ You want something quiet: We noticed that it can get a bit noisy, so it may not be the best option for bedrooms.

🔎 Dyson Purifier Cool: Sleek, stylish and packed with useful features, this air purifier delivers a great air-cleaning performance. Plus, it keeps you cool during the summer months. However, it is relatively noisy and it requires a steep upfront investment. ★★★★

As with any Dyson product, a sleek and well-engineered design was to be expected of the Dyson Purifier Cool — we think it's one of the most stylish air purifiers on the market. This appliance definitely doesn’t disappoint on those grounds, and has a practical edge too, doubling as a cooling fan, giving you more bang for your buck.

Beyond aesthetics, this purifier also performed exceptionally well in our testing protocol during our full Dyson Purifier Cool review, with our tests concluding that it often captured more than 95% of monitored particles when used at its highest setting for at least 30 minutes.

When it comes to assisting with cleansing the air of allergens, the Dyson Purifier Cool aims to pick up microscopic particles smaller than 2.5 microns, including smoke, bacteria, and allergens — shown as PM 2.5.

If you want your home to be a relief from allergy symptoms - especially in peak pollen season for example — then another neat trick with the Dyson Purifier Cool is that you can set your machine to start working remotely, all from the comfort of your machine’s app.

Though this air purifier might not be within everyone’s price range, it has a lot to deliver, and an eye-catching design to sweeten the deal.

Best tower fan: Runner-up

Best tower fan: Runner-up

The Dreo MC710S air purifier tower fan is cheaper than the Dyson Purifier Cool by around $300, but it does offer similar perks: powerful airflow, good air-cleaning performance and a plethora of smart features. However, it is not as stylish or durable.

Read our full review

Our expert review:

✅ You want to mount it on your wall: If you want to save on floor space, you can mount it to your wall.✅ You want something you can customize: You can customize the six filters, and for an extra $20 you can even choose an artistic front panel to help disguise it in your home.

❌ You don't want to spend a lot: This is one of the most expensive purifiers on this list.❌ You want simplicity: It comes with an accompanying app, which we found to be tricky to use.

🔎 Rabbit Air MinusA2 Spa-780N: It may be one of the pricier air purifiers in this guide, but this stylish machine is well worth the money. The MinusA2 offers excellent performance, customizable filters, a robust filtration system and a handy smart app. ★★★★½

If you struggle with allergies and are looking for an inconspicuous air purifier to add to your home, then the Rabbit Air MinusA2 Spa-780N has a design that’s made for sleek, stylish homes.

Able to be wall-mounted or used as a portable purifier, this appliance is impressive on many counts. It has a standard coverage of 815 square feet, which is perfect for larger spaces, and a CADR capable of trapping pollen, dust and smoke in your designated space within that size. It’s crucial when shopping for an air purifier for allergies that you look out for a solid clean air delivery rate (CADR), and this air purifier claims to have high delivery rates with all of those allergens.

When it comes to selecting an air purifier for your home, there are a number of practical features to think about too. This Rabbit Air MinusA2 Spa-780N has been engineered to be ultra quiet, which is bound to be a top consideration for light sleepers. Having said this, we measured 48 decibels on turbo speed during our Rabbit Air MinusA2 Spa-780N review, so it's not quite as quiet as advertised.

The design of this air purifier means you probably won’t even notice that it’s there (especially with the wall mount option) but you’re bound to feel its benefit when it comes to air quality. In our tests, it removed between 84-90% of particles between 0.3 and 10 microns in size in just 30 minutes.

Our expert review:

✅ You have a large space: It's best suited for large spaces, both in size and effective range.

✅ You want to keep a close eye on air quality: This unit will tell you exactly how much of each type of airborne pollutants lingers in the air.

❌ You're on a budget: It is an impressively powerful air purifier, but it does come at a steep cost.

❌ You want something quiet for your bedroom: We found it was quite loud on its highest fan setting.

🔎 Molekule Air Pro: This elegant air purifier boasts impressive air-cleaning performance and some of the best air quality readings out there. It is relatively big and expensive, though. ★★★★

The Molekule Air Pro provides some of the most comprehensive air quality readings we have seen in a commercial air purifier. Unlike most appliances on the market, it tells you exactly how much particulate matter is lingering in the air at any given time, breaking it down into 1-micron, 2.5-micron, and 10-micron particles, volatile organic compounds (VOCs), carbon dioxide and relative humidity. All of the data collected by the Molekule Air Pro can then be viewed in the Molekule app, so you can have a detailed overview of air pollution changes over time. If you like your numbers or are concerned about a specific type of airborne allergens, this air purifier will thoroughly impress you.

It is not just the air quality readings that make the Molekule Air Pro stand out among its competitors. This air purifier is one of the handful of models cleared by the FDA as a Class II medical device under the 510(k) program. That is because it is equipped with a patented pollutant-destroying PECO technology that can turn pollen, dust mites and other organic airborne allergens into water vapor and harmless gases — and it showed in our tests.

During our Molekule Air Pro review, we were impressed by its powerful air-cleaning performance. This appliance did a particularly good job at removing smoke, trapping 99.6% of particles measuring 0.3 microns and 99.9% of 2.5-micron particles after just 15 minutes on Auto mode. The Molekule Air Pro delivered even better results when we repeated this test at its highest fan setting. The problem is, this air purifier was relatively loud when put through its paces, reaching up to a whopping 66dB — as loud as a regular conversation. It can, however, be put in a Quiet Mode.

High cost is another downside. Priced at roughly $1000, the Molekule Air Pro is one of the most expensive models in this guide, and its filter replacements are pricey, too.

Our expert review:

✅ You want versatility: This air purifier also doubles as a humidifier.✅ You want smart features: It comes with a remote control and can be controlled via the Smart Life app.

❌ You don't want to spend loads: It's on the pricier side, so those with a smaller budget will want to look at other options.❌ You don't have a lot of space: It's a fairly bulky unit, so it wouldn't be suitable for smaller spaces.

🔎 Turonic PH950 2-in-1: This stylish purifier-humidifier combo impresses with its user-friendly design, powerful air filtration system and efficient performance — but it is also quite bulky and pricey. ★★★★½

When it comes to air purifiers, Turonic may be a new kid on the block — but don’t let that put you off. The Turonic PH950 2-in-1 model may be a strong contender for the title of best mid-range air purifier.

Weighing in at almost 24 lbs, it's definitely not the lightest piece of equipment on the market. It is also bigger and wider than most competitors, so you may need to sacrifice some floor space. But taking into account what the Turonic PH950 can offer, this is not necessarily a deal breaker.

Indeed, the Turonic PH950 is a powerful 2-in-1 machine combining an air purifier and a humidifier. This complex piece of equipment is equipped with an ionizer, UV-C technology and several different filters designed to neutralize up to 99.98% of unwanted particles as small as 0.1 microns. It also comes with 10 different operating modes, a handy remote control, a designated app, a timer, PM2.5 laser air quality sensor, and a child lock — all for approximately $400 per unit. It may sound like a hefty price tag, but we found the Turonic PH950’s performance to be superb in our tests. And since this piece of equipment is highly energy efficient, it will not rack up your energy bills.

During our Turonic PH950 air purifier review, we found it easy to assemble and use. It is equipped with a stylish circular display and easy-to-understand color-coded indicators. The display is also suitable to use in a bedroom at night, as the icons are bright, but not flashy.

The downsides? For a relative beginner, the Turonic PH950 may seem like an overly complicated piece of machinery. Changing a filter in this piece of equipment can also prove quite costly — the price for a single filter pad tends to fall between $45 and $60.

Our expert review:

✅ You want smart features: It's easy to control with your voice or through the app.✅ You have pets: It's designed specifically for homes with pets.

❌ You have a small space: It's not a small unit, so there are better options for those who are tight on space.❌ You want to save money: There are cheaper Levoit models available.

🔎 Levoit Vital 200S: This smart air purifier harbors a real beast of performance — it is whisper-quiet, easy to use and efficient at removing airborne allergens. It comes with an app and dedicated pet mode, too. ★★★★½

Putting the Vital 200S through its paces during our Levoit Vital 200s review, we found it impressive and efficient at removing particles measuring as small as 0.3 microns. Pet dander, mold, dust and smoke were absorbed while chemicals and odors from everyday household cleaning and cooking were neutralized by the three-stage filtration system. This includes a washable pre-filter, an H13 True HEPA filter and a high-efficiency activated carbon filter.

While the large boxy design may not be suited to users who want a sleek and stylish air purifier, or those with small rooms, the no-frills aesthetic makes the Levoit Vital 200S the perfect choice for most users. While it’s not cheap, it is relatively affordable, and if you value clean indoor air quality, you won’t be disappointed with its performance.

The Levoit Vital 200S offers four fan speeds, three separate modes including pet, auto and sleep mode, and a connected app that allows you to control your air purifier remotely, wherever you are. It also works with Google Assistant and Alexa voice control devices.

The Vesync app is easy to use and allows users to track their real-time air quality data and historical data, revealing peaks in poor air quality over the day and taking the guesswork out of what’s causing bad air quality in your home.

Our expert review:

✅ You have a large space: This air purifier is best suited to large, airy rooms or commercial spaces.✅ You want smart features: It has app connectivity and smart features.

❌ You're on a budget: It's not a cheap unit, so anyone on a budget might want to consider more affordable options.❌ You're short on space: It's quite a big unit, as expected, so you'll have to ensure there's room around it.

🔎 DH Lifelabs Sciaire + HEPA Air Purifier: Big and bold, this air purifier delivers a powerful air-cleaning performance without making much noise or requiring extensive maintenance. It is, however, on the expensive side. ★★★★

The Sciaire+ HEPA air purifier by DH Lifelabs is designed to maintain clean and germ-free living spaces efficiently. It utilizes 16 ion generators to bond with airborne particles actively, achieving a 99.99% elimination rate of bacteria and viruses. The 3-in-1 filter system, including pre-filter, HEPA filter, and activated carbon filter, effectively removes particles as small as 0.1 microns, addressing pet dander, pollen, dust, allergens, and volatile organic compounds (VOCs).

The purifier also features a dual air deodorization process, breaking down odors and neutralizing unpleasant smells. It covers areas up to 452 sq. ft., with Wi-Fi connectivity and app control. The design is big, though, measuring 35.4 inches in height and 13.6 inches in diameter. It may be too large for smaller homes. It performed well in our DH Lifelabs Sciaire + HEPA Air Purifier review and was super-quiet during operation, even on auto-mode.

With a 4.6 out of 5-star rating on Amazon, users enjoy how easy it is to use and how well it performs. However, they raise concerns about its size being more suited for commercial premises and the potential expense of filter replacements.

Due to its large size, we’d recommend the DH Lifelabs Sciaire+ HEPA Air Purifier for those with spacious homes or commercial spaces. Despite its substantial dimensions, it offers efficient air purification and ease of use, making it a suitable choice for the right environment.

Dr. John McKeon, MD, is the CEO of Allergy Standards, an international certification body for domestic appliances and household products. He is a principal at the Indoor Air Innovation & Research (iAIR) Institute, a trade association aiming to enhance indoor air quality in homes, commercial buildings and schools. Dr. McKeon also works as an adjunct professor in the Centre for Practice and Healthcare Innovation, a research center based at Trinity College Dublin in Ireland. He advised Live Science on where to put an air purifier and how to choose the best appliance for your needs.

Kathy Przywara is the Vice President of Community at the Asthma and Allergy Foundation of America (AAFA). She oversees AAFA’s Support Center, a community dedicated to providing patients with direct support and educational resources on asthma and allergy management. Kathy Przywara also directs digital outreach for this not-for-profit organization. For this piece, she commented on whether air purifiers can help with mold and pet allergies, and discussed the potential effects of ionizers.

Dr. Sameer Nakedar is a medical doctor and the chief medical officer at Welzo, a personalized healthcare service based in London, England. He is a portfolio general practitioner with a particular interest in promoting digital technology solutions in medical settings. Sameer has built several cross-platform applications used by primary and secondary healthcare providers worldwide. He told Live Science about the potential benefits of air purifiers for managing asthma and allergies.

Abbas Kanani is a qualified independent prescriber and a superintendent pharmacist at Chemist Click, an online pharmacy based in England. He is a member of Royal Pharmaceutical Society, National Pharmacy Association and General Pharmaceutical Council. As a consultant for the National Health Service, Abbas also provides advisory services on cost savings and clinical efficiencies. For this piece, he compared the potential benefits of air purifiers and humidifiers on managing asthma and allergies.

Remember to keep your air purifier clean, and change your HEPA filter as recommended to ensure that it keeps running correctly. You can buy reusable filters that only require cleaning, but these do have a limited life expectancy and will still need to be completely replaced eventually.

Try to adhere to the room-size specifications that come with your air purifier for the most effective air cleaning possible. If placed in rooms with high foot traffic or rooms too large for their capacity, air purifiers will not clear the air of irritants as well as if they are used correctly. Don't forget to wipe down the outside of your machine with a dry or slightly damp cleaning cloth.

“The best placement for an air purifier depends on your specific needs and the type of allergens in your home,” McKeon said. Bedrooms are often viewed as good places to put an air purifier, since we spend so much time there and that air pollution has an impact on our sleep quality. But if you or members of your household are allergic to pet dander or pollen, it may be better to keep an air purifier in a living room or other areas that are frequently visited and close to the source of those allergens, he explained.

Make sure your air purifier can accommodate the size of the room it is being placed in, Przywara said. If placed in areas with high foot traffic or rooms too large for their capacity, air purifiers will not clear the air of irritants as well as if they are used correctly. Air-cleaning appliances have ratings that indicate the volume of air they can clean in a fixed amount of time and space — the Clean Air Delivery Rate (CADR), for example. "If you purchase an air cleaner with a CADR rating too low for your room, it will be ineffective," Przywara said.

Ionizers are devices that release negative ions — electrically charged molecules that pass their extra electrons onto other airborne particles, causing them to clump together and fall to the ground. "Ionizers can help remove tiny airborne pollutants, such as bacteria and viruses, but they are relatively ineffective at removing larger particles like pollen and house dust allergens," Przywara said.

Mold allergy is caused by mold spores, tiny cells that mold release into the air to find a moist ground and reproduce. Air purifiers with HEPA filters may prevent mold spores from spreading, but they will not stop the infestation. "For effective mold allergy management, it's crucial to locate and eliminate any mold growth sources in the home, such as damp areas, leaks, or water damage," McKeon said. Combining an air purifier with a dehumidifier could be more effective than using an air purifier alone, he noted.

Pet allergies are caused by proteins in the animal’s dander (dead skin cells), saliva, and urine. When those proteins get into your airways, eyes, or on your skin, they trigger an allergic reaction. "Using an air purifier with a HEPA filter at least four hours per day can help reduce these allergens in the air," Przywara said. However, pet allergens can collect on furniture and other surfaces, and they can be stirred into the air again by dusting, vacuuming, and other household activities, she said.

Hay fever can be triggered by a wide range of airborne substances, but it’s predominantly caused by pollen, Dr. Sameer Nakedar, a medical doctor and chief medical officer at Welzo, a personalized healthcare provider based in London, England, told Live Science. ”The most common allergens that cause hay fever include tree, grass and weed pollen. Grass pollen is by far the most common, it affects up to 95% of sufferers,” he said. Mold spores and animal dander can also contribute to hay fever symptoms. “However, these allergens are not specific to hay fever, and they can trigger allergic reactions in some people all year round,” Nakedar said. Pollen, animal dander and other common indoor allergens are relatively large particles. According to the U.S. Environment Protection Agency (EPA), “some controversy exists about whether air cleaners can reduce the allergic reactions” produced by such sizable allergens. They don’t tend to linger in the air, but rather end up settling on surfaces in the home, such as cushions or carpets. Air purifiers may not be able to remove these allergens unless they are “disturbed and re-suspended in the air,” EPA said.

Complicating the situation, two individuals with the same allergy may have vastly different reactions to the same amount of allergens present in the air. Some people may experience mild symptoms, while others may have more severe or persistent issues, Nakedar said. As a result, it is likely that the same air purifier may have a different impact on hay fever symptoms, depending on one’s sensitivity to allergens.

Moreover, air purifiers are not created equal. They come in many shapes and sizes and with many different technological solutions. Therefore, some air purifier models may be better at easing allergic reactions than others. For example, machines equipped with HEPA filters may be more effective at reducing airborne allergens than air purifiers which use different filters. According to the EPA, High Efficiency Particulate Air Filters, commonly known as HEPA, have been shown to reduce at least 99.97% of dust, pollen, mold, and any other airborne allergens with a size of 0.3 microns (µm). At the same time, some HEPA filters are more complex than others, and it is likely that such differences in the design have an impact on their overall effectiveness.

Abbas Kanani, a superintendent pharmacist at Chemist Click, an online pharmacy, told Live Science:

“Dry air can exacerbate respiratory conditions and allergy symptoms, as it can irritate the nasal passages and throat,” he said. “Humidifiers work by adding moisture to the air to combat dryness. By increasing humidity levels, they can help alleviate dryness, soothe irritated airways, and provide relief for nasal congestion and dry coughs. A combination of both a humidifier and an air purifier may be beneficial in some cases, particularly during the winter months when indoor air tends to become dry due to heating,” Kanani said.

However, humidifiers may not be suitable for people with dust mites and mold allergies, according to the AAAAI. Mold spores tend to grow rapidly in places with excessive moisture, such as bathrooms, roofs or windows. Dust mites - microscopic, insect-like pests that feed off dead human skin cells - also thrive in humid environments. According to the EPA, humidity levels above 60 percent may vastly increase the number of these allergens in the environment, while levels between 30 and 50 appear to keep dust mites and mold spores at bay. Unfortunately, many humidifiers do not come with humidity meters and extensive moisture control settings, which makes it more difficult to adjust their output.

In addition, humidifiers themselves may add to the mold problem, AAAAI said. If the filters are not cleaned or changed on a regular basis, it can create a perfect environment for mold spores to grow within the unit. This in turn can lead to humidifiers blowing a vapor containing a high number of allergens. To prevent that from happening, the AAAAI recommends using distilled or demineralized water. Minerals found in tap water may increase the growth of pathogens and spores, as well as create white dust that can irritate the sinuses and contribute to allergy symptoms.

While all air purifiers are designed to remove harmful particles from the air, not all models can be helpful with easing allergy symptoms. Seemingly similar models may use different filters and offer vastly different technological solutions. This can make some air purifiers way more effective at removing specific airborne allergens than others. When choosing a model, look out for certain features. If your aim is to reduce allergens in your home, your best call is to pick an air purifier equipped with a HEPA filter, Nakedar told Live Science.

HEPA filters, short for "High Efficiency Particulate Air [Filter]", are mechanical air filters composed of a mesh of randomly placed fibers. According to the U.S. Environmental Protection Agency (EPA), HEPA filters have been shown to remove at least 99.97% of airborne allergens with a size of 0.3 microns (µm), including pollen and mold spores. It needs to be stressed, however, that most studies into HEPA filters were conducted in highly regulated laboratory conditions, and there are only a handful of studies that investigated the effectiveness of HEPA filters in reducing allergy symptoms in human subjects. Nevertheless, the results are promising. For example, a 2020 clinical trial published in the Yonsei Medical Journal found that patients with dust mite allergy may need fewer allergy medications following six weeks of exposure to air purifiers equipped with HEPA filters.

Moreover, certain air purifier models may actually exacerbate your allergy symptoms, rather than alleviate them, ACAAI said. For example, ionic electrostatic air purifiers work by releasing ions - molecules with an electric charge due to the loss or gain of one or more electrons - which then force harmful airborne particles to stick to walls and other household surfaces. Although this helps to clean the air from allergens, it does not remove them permanently. Moreover, ionic air purifiers are known to produce ozone, a gas molecule composed of three oxygen atoms, ACAAI warned. And according to the American Lung Association (ALA), ozone can irritate the airways and nasal passages, increasing the risk of respiratory problems and potentially aggravating hay fever symptoms. In addition, some ionic air purifiers come with additional UV light, which aims to kill bacteria and other harmful pathogens. However, there is no scientific evidence that this feature can be effective for alleviating allergic reactions, ACAAI said.

If you are unsure whether an air purifier is suitable for people with allergies, check whether it has been independently tested. "For example, CERTIFIED Asthma and Allergy Friendly air cleaners have been tested to show they remove more than 90% of airborne allergens like cat dander and dust mite allergens," McKeon said. "This certification mark also ensures the product meets AAFA’s high standards," Przywara noted.

Another feature to look out for is the Clean Air Delivery Rate, or CADR, according to The American College of Allergy, Asthma & Immunology (ACAAI). The CADR value measures how fast a certain number of airborne particles can be trapped by an air purifier. Even the most technologically advanced air purifier may struggle with removing allergens if it’s not big or powerful enough to cover enough space. When picking your model, make sure its CADR matches the size of the room where you intend to use it, ACAAI recommends.

Lastly, choose an air purifier that comes with affordable replacement filters, Kanani told Live Science. Filters need regular changing to maintain the device's efficiency, which is particularly important during heavy pollen season, he said.

Our reviewers. We know a great deal about the best air purifiers for allergies — and not just the theory. Many of our expert reviewers know firsthand what it is like to struggle with adverse reactions to pollen, pet dander, mold spores and other airborne allergens. We have spent years trying and testing different appliances, in the everlasting pursuit of an air purifier that can truly help us keep the allergies at bay. You can put trust in our verdicts, because we use these appliances ourselves and we can personally vouch for their reliability.

However, we know that our word may not be enough. Not to mention, everyone has their own unique set of allergic triggers — what works wonders for one person may not work for someone else. So to be as objective as possible, we tested each air purifier in this guide to the exact same standards, using the same procedures and review protocols.

Design. When assessing the design of an air purifier for allergies, we take into account multiple different factors. First and foremost, we make sure that the unit is equipped with a HEPA-style filter capable of trapping miniscule airborne pollutants. Once this condition is met, we look into the size, looks and ease of use of the air purifier in question. Then, we check whether it comes with any additional allergy-busting measures, such as pre-filters and pollutant-destroying technologies. We also look into the energy consumption of the unit, the cost of replacement filters and the terms of the warranty.

Features. We take a good look at the features of an air purifier to fully understand what this appliance has to offer. Does it come with an ionizer, UV sanitizer and other potentially helpful add-ons? How many modes and fan speeds does it have? Can it be operated remotely? Does it come with an air quality monitor, and if so, how detailed are the readings? Also, does it have any smart features or connected apps? Then, we give our verdict on the functionality of the air purifier in question.

Performance. This is the most in-depth part of our testing process. We conduct multiple performance tests using an industry-grade Perfect Prime AQ9600 air particle monitor, a device capable of detecting airborne pollutants as small as 0.3 microns — which is the size of many allergens and tobacco smoke particles. We want to know exactly how much of particulate matter the air purifier can remove, and whether there are any circumstances that can impede or speed up the purification process.

We start by running an ambient air quality test. We put the air purifier in an enclosed, medium-sized room in a home, take baseline air quality measurements, and then run it for half an hour on different settings (including an auto mode when applicable). We make note of air quality readings after 15 and 30 minutes, then calculate the percentage of particulate matter removed by the air purifier. We also measure the noise levels generated by the fan, to comment on how noticeable the purifier will be in an average home.

Next, we conduct smoke tests. We burn a bunch of matches and incense sticks to generate heavy pollution, then run the air purifier for half an hour on the highest fan settings (and auto mode, if applicable). We make note of changes to air quality readings after 15 and 30 minutes, then calculate the percentage of particulate matter removed by the machine. Lastly, we repeat the tests in different rooms to fully assess the appliance's capabilities.

What the users say. Finally, we check online user reviews to see what people think about their air purifier, and we test for any persistent problems or defects that we read about.

As per our testing policy, we fully disclose all our findings in our reviews.

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Molly Cleary is an ecommerce editor at Livingetc and Homes and Gardens, and was previously a writer at Top Ten Reviews. For Live Science, she covers a range of subjects including fitness, health and homes. Molly graduated from the University of Exeter in the UK. with a degree in English Literature, and previously undertook internships at The Economist.

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