According to the Asthma and Allergy Foundation of America (AAFA), we spend 90% of our time indoors, and our indoor environment can have all sorts of allergens and other irritants. That includes mold, pet dander, dust, and chemical emissions from everyday household products. In fact, the EPA estimates indoor air may be two to five times more polluted than outdoor levels.
An air purifier limits the number of triggers for asthma sufferers and anyone with respiratory difficulties, says Ravi Pandey, MD, an internal medicine specialist on staff at several South Florida hospitals. An additional health benefit is limiting virus transmission, he said (though don't expect it to eliminate the risk of contracting coronavirus).
An air purifier is also helpful for cleaning the air when simply opening the window won't do the job, such as when the pollen counts are high or if you live in an area where smog or wildfires are common.
We tested 26 models (details on our testing methods here) and consulted three experts to determine the best air purifiers. All of the units we recommend performed well in our tests, are easy to use, and have reasonable long-term filter replacement and energy use costs.
Here are the best air purifiers of 2021
- Best air purifier overall: Honeywell PowerPlus True HEPA Allergen Remover/Air Purifier
- Best budget air purifier: Lasko LP300 HEPA Tower Air Purifier
- Best smart air purifier: Blueair HealthProtect 7470i Smart Air Purifier
- Best ionizing air purifier: Alen BreatheSmart Classic Air Purifier
Updated on 6/2/2021: We updated our recommendations based on the testing of two new air purifiers. We're also conducting long-term tests of our top models and are trying out new ones, including the Dyson TP07.
SEE ALSO: The best humidifiers you can buy
The best air purifier overall
If you need a powerful air purifier for a medium-to-large room, the Honeywell PowerPlus True HEPA Allergen Remover/Air Purifier is your best option.
- Clean air delivery rate (CADR): 335 cubic feet per minute (cfm) 335
- Recommended room size: 637 square feet
- Weight: 20.6 pounds
- Dimensions: 10.79 x 19.13 x 22.3 inches
- Energy Star-certified: Yes
- Auto mode: Yes
- Type of filter(s): True HEPA and prefilter
- Filter replacement: $79.99 yearly
Pros: Did the best job in our air purifying test, easy to set up and maintain, widely available filters, has the highest CADR of any unit in our guide, Energy Star-certified
Cons: Heavy, loud operation on high fan speed, expensive filter replacements
The Honeywell PowerPlus True HEPA Allergen Remover/Air Purifier (model number HPA3300) was the top model when looking at the combined performance in our volatile organic compound (VOC) and particulate matter testing. A little over an hour into our test, it had removed 99% of the particulate matter. Also, the VOC levels were among the lowest at the end of the testing period. While it hasn't specifically been certified by AAFA, these numbers suggest this is an excellent air purifier for allergy sufferers and for people sensitive to other irritants.
Setup was quick and intuitive — just remove the packaging and plug the unit in. And, there's little maintenance. Just wipe the unit down with a dry cloth every three months. When the filter indicator light turns on (approximately once a year) replace the three true HEPA filters, which are widely available.
The HPA3300 isn't without its negatives. First, it's one of the loudest models we tested. When on low fan speed, it's no louder than the surrounding noise, but on high, it registered 58.9 decibels (dB), which is about as loud as a normal conversation. At over 20 pounds, it isn't as portable, though it does have a handle to help with transport.
That said, it's similar to most models in power use and filter replacement costs, and we think its performance makes it the best air purifier overall, especially for allergy sufferers and for medium-to-large rooms.
Best budget air purifier
If you're on a budget and want to clean the air in a smaller room, the Lasko LP300 HEPA Tower Air Purifier is your best bet with its good purifying capabilities and low upfront and filter costs.
- CADR: 115 cfm
- Recommended room size: 219 square feet
- Weight: 9.8 pounds
- Dimensions: 7.3 x 10.3 x 21.64 inches
- Energy Star-certified: No
- Auto mode: No
- Type of filtering: True HEPA and carbon
- Filter replacement: $29.99 yearly
Pros: Did a good job of removing VOCs and particulate matter in our tests, low filter replacement costs, easy to maintain and transport
Cons: No auto mode, high power use, not suitable for larger rooms
The Lasko LP300 HEPA Tower Air Purifier is $65 cheaper than any other unit tested; has the lowest filter replacement cost; and at under 10 pounds, doesn't feel like a heavy-duty appliance.
We found it performed just as well as models that cost three or four times as much. The Lasko air purifier removed airborne dust and debris quickly. With 30 minutes to spare in the testing period, our air quality monitor didn't register any particulate matter. Though its performance wasn't as impressive with VOCs, it did a good job of keeping the levels in a safe range.
Setup was straightforward and took about five minutes. The light weight makes the Lasko easy to move around so you can take it with you from room to room, which you may need to do since its low CADR makes it better suited for small rooms. If you need more oomph, consider the LP450, which is only $35 more and covers twice as much space.
The Lasko was one of the few units we tested that was louder than ambient sound levels even when on low. At 45.6 dB on low, it was a little bit louder than a typical library. On high, it was only 51.6 dB.
The biggest negative with this model is that it uses a lot of power. It used five times as much electricity as our top pick. This is likely due to it not having an auto mode that adjusts with the air quality, which is another negative.
Best smart air purifier
The Blueair HealthProtect 7470i Smart Air Purifier is the ideal air purifier for techies, with its data-rich app, easy scheduling, and Alexa and Google Assistant compatibility.
- CADR: 270 cfm
- Recommended room size: 513 square feet
- Weight: 27.2 pounds
- Dimensions: 11.8 x 11.8 x 27.2 inches
- Energy Star-certified: Energy Star rated as "energy-efficient"
- Auto mode: Yes
- Type of filtering: HEPA-type and prefilter
- Filter replacement: $69.99 yearly
Pros: Among the best at reducing VOCs and particulate matter from the air, affordable and widely available filters, quiet operation, easy to clean, powerful enough or medium-size rooms, useful and data-rich app, voice control
Cons: Heavy, lacks handles, app didn't connect easily and sometimes lags
The Blueair HealthProtect 7470i Smart Air Purifier is the most high-tech model we tested. It features a digital color touchscreen that allows you to operate the appliance and track the temperature, humidity, and air quality for VOCs and three different particle sizes.
The Blueair app (available for iOS and Android) puts the data and functions at your fingertips wherever you are, including setting a schedule. It's also compatible with Alexa and Google Assistant. I found the app worked well for the most part, though there were times when the data readouts took up to an hour to refresh. Also, connecting to the app upon initial setup took a few tries, which added 10 minutes to the setup process.
The HealthProtect 7470i has a HEPA-type filter (see our FAQ for how this differs from a true HEPA filter) that looks like a partially open book and features an RFID chip that tracks the filter life. The filters are comparatively affordable and can be ordered in the app or through major retailers, including Amazon. Other than replacing the filter, the only other maintenance is occasionally vacuuming or washing the two prefilters.
In the air quality tests, the Blueair purifier performed well. It had one of the lowest VOC readings after the two-hour testing period. And it removed 99% of the particulate matter. It did this while remaining quiet. On low, I couldn't hear it at all.
The power consumption was about average among the units I tested, which is impressive considering the mid-range CADR. If you're looking for a model that can cover a larger area, consider the HealthProtect 7770i, which purportedly can clean the air in a 760-square-foot room in 15 minutes.
I found the Blueair HealthProtect 7470i is a little too unwieldy to easily move from room to room. At 27.2 pounds and without good handles, you'll likely want to keep this purifier in one spot.
Best ionizing air purifier
The Alen BreatheSmart Classic Air Purifier uses ionization and a true HEPA filter to quickly remove particles from your air, while operating quietly.
- CADR: 231 cfm
- Recommended room size: 439 square feet
- Weight: 22.6 pounds
- Dimensions: 10 x 17.75 x 26.75 inches
- Energy Star-certified: No
- Auto mode: Yes
- Type of filtering: True HEPA, carbon, prefilter, ionizer
- Filter replacement: $59 every 10 to 12 months
Pros: Low-ozone ionizer, great job of quickly removing particulate matter, quiet operation, easy setup and maintenance, affordable and widely-available filters
Cons: Poor VOC removal, hard to transport, heavy energy use
While we don't recommend ionizing air purifiers for most people (read why here), we thought it was important to include a model with an ionizing option, for those who are particularly concerned about bacteria and mold growth in their home (which is the primary reason to consider an ionizing air purifier). We specifically looked for units that allow you to toggle the ionizer on and off and offer HEPA filtration when the ionizer is not in use. With its true HEPA filter, the Alen BreatheSmart Classic Air Purifier is the best unit meeting these criteria.
You can choose to use the Alen BreatheSmart Classic with or without the ionizer. When the ionizer is engaged, Alen states that it produces less than 0.05 ppm ozone. The purifier is also certified ozone-safe by the California Air Resource Board.
In our air quality test, the Alen BreatheSmart Classic was the fastest to remove the particulate matter, registering a reading of zero on the air quality monitor within an hour of operation. However, it came in below average at reducing VOCs.
The purifier got the job done without causing a racket. On low, it's no louder than the ambient noise in the test room.
Its a quite attractive air purifier and comes in nine colors to match your decor. I chose espresso to complement our wood floors. Setup was quick and pretty standard. It's relatively heavy and only has one handle so you may want to keep this purifier in one location.
The only maintenance is vacuuming or washing the prefilter and wiping down the air quality sensor. The unit lets you know when it's time to replace the filter, which is affordable and widely available.
However, you will likely have higher electricity costs with this purifier, as it was one of the biggest power users we tested.
What else we tested
Over the last year, I've tested 26 air purifiers, and there are several that we almost included in our guide that are still worth considering:
What else we recommend and why:
Brondell Horizon O2+ ($139.99): For how affordable this Brondell air purifier is, it did an outstanding job, and I'd recommend it if our top budget pick isn't available. It was one of the top removers of particulate matter in our tests and was easy to maintain and clean. The biggest negative is that it doesn't have an auto mode that adjusts the fan speed based on air quality. This would have been nice since it consumes a lot of power.
Blueair Blue Pure 211+ Auto ($339.99): This is the updated version of the Blueair Blue Pure 211+, the top pick in our previous version of this guide. The main addition is an auto mode, which adjusts the filtering speed and intensity based on the air quality. We found it did a good job of filtering the air while using minimal electricity, but it was one of the loudest units, and filters are expensive and only available on the Blueair website.
Honeywell HPA300 ($229.99): This model was our best budget pick previously, but our new budget pick outperformed it in our tests and is half the price. We almost chose it as the best for allergy sufferers, but we preferred the Honeywell HPA3300 because it has an auto mode and did a better job of removing particulate matter.
RabbitAir MinusA2 ($599.95): If we had a "most visually appealing" category, this model would win. It was previously our best wall-mounted unit for large rooms, but we ditched that clunky category. We also weren't particularly impressed with how well it did cleaning the air. However, it was easy to set up and maintain. Plus, the filter replacement costs are reasonable.
Coway Airmega 400S ($519.00): Our previous pick for best smart air purifier, the Coway Airmega 400S is an attractive unit that barely makes any sound and adjusts the fan speed based on the air's pollution level, which lends itself to low energy use. It lost its title due to its average performance in our purifying tests and its smart features aren't as fancy as our new smart pick.
Coway Airmega AP-1512HH Mighty ($181.12): This was our best ionizer in the last guide. We like that it has three stages of filtration and adjusts the fan speed based on the air quality, which led to low power usage. However, in our tests, it was noisy, did poorly removing VOCs, and was just average at removing particulate matter.
PurO²xygen P500 ($199.97): If our budget pick isn't available, we think this is a suitable alternative. It didn't perform poorly in any test. In fact, it was among the best at reducing VOCs and was easy to set up and move around. It was only average in other areas and doesn't beat out the picks in any of our categories.
Alen Breathesmart 45i ($483.00): This Alen air purifier relies on a medical-grade H13 true HEPA filter, which did an outstanding job of removing particulate matter from our test room. This model is also easy to set up, transport, and maintain. However, filter replacement will set you back about $140 per year, and it didn't do well reducing VOCs in the air.
Mila ($358.00): Mila is an affordable smart air purifier that has a variety of filter options (only available on the company's website) depending on what air quality issue you most want to address. I received several filters, but I only had time to test the most heavy-duty one, The Overreactor, which is a hospital-grade H14 HEPA filter. There wasn't anything that made this unit stand out, though. It was in the middle of the pack in our air purifying tests, but it was louder than most.
PhoneSoap AirSoap ($399.99): The biggest reason the AirSoap isn't in our guide is because it relies on ionization to clean the air, and there is no way to turn it off. The benefits of ionization are questionable, and there's a risk of negative health issues due to the low levels of ozone the AirSoap produces. However, it did well in our air purifying tests, operates quietly, doesn't have filter replacement costs, and is easy to set up and transport.
Aura Air Mini ($179.00): Like the AirSoap above, the Aura Air Mini relies on ionization to clean the air. It's unique in that it is only three inches deep and wide and 4.5 inches high. And, it runs for up to six hours on a single charge. It's designed to be used in small spaces, but we're not sure of the use cases. You wouldn't want to use it in public and potentially expose vulnerable individuals to ozone. And, in your car, you already have a filtration system.
What we don't recommend and why:
Dyson HP09 ($749.99): The HP09 is a new model from one of the top names in the industry, and it does an outstanding job of heating and cooling rooms up to 800 square feet in size. The only problem is it was one of the worst performers in our air purifying tests. At this price point, it needs to do better to get our recommendation.
Honeywell Insight HPA5300B ($289.99): I like the looks of this air purifier, and it's easy to maintain and has widely-available filters. However, it used a lot of electricity and is loud on high speed. Plus, its performance in the air purifying tests was unimpressive. Go with the Honeywell HPA3300 instead.
IQAir Atem ($399.00): We were hoping this would be a good compact option, but it performed poorly in the air purifying tests and has high upfront and filter costs.
BetterAir Biotica800 ($399.99): The Biotica800 releases a probiotic mist for 30 seconds every 70 minutes. It runs quietly during those 30 seconds, and it's electricity use was too low for our smart plug to register anything. However, if it does anything to clean the air, our air quality monitor didn't notice.
EnviroKlenz Air System Plus ($789.00): This is the heaviest and least visually-appealing purifier we tested. It's designed to take a beating and is used by the US Navy. The Air System Plus relies on a HEPA filter, proprietary air cartridge, and UVC bulbs. It was one of six models to register a reading of zero particulate matter at the end of our testing period. However, it had the highest VOC reading at the end. It doesn't have an auto mode, used the most electricity, and has the highest filter costs of the bunch.
Our testing methodology
I've been reviewing heating, cooling, and air quality devices for the past three years. For this guide, I personally tested 26 air purifiers for at least one week each and consulted with Ravi Pandey, MD, an internal medicine specialist on staff at several South Florida hospitals; Junfeng Zhang, PhD, professor of global and environmental health at Duke University; and Bryan Buckley, the brand manager for One Hour Heating & Air Conditioning.
Based on my research and interviews with experts, the most important features to consider when shopping for an air purifier are its ability to remove irritants from the air, long-term costs, and ease of use.
Here are the main ways we test each model:
Purifying: I burned incense in a 200-square-foot room with the windows and doors closed and used an air quality monitor to take measurements of the VOCs and particulate matter in the air every 15 minutes. After the incense burned for 15 minutes, I turned on the air purifier's auto mode, which adjusts the fan speed based on the air quality. If it didn't have an auto mode, I used the highest setting. I looked at both the percentage removed and the amount of VOCs and particulate matter left over after two hours. For context, all of the recommended room sizes in our guide are calculated assuming an eight-foot ceiling and four air changes per hour (ACPH).
Setup: I timed how long it took me to set up the air purifier from the moment I opened the box until the unit was running. This includes connecting to an app when applicable. I made note of any unusual or confusing steps. Most models only required removing the packaging and plugging in the unit. This generally took five minutes or less.
Portability: I moved the air purifiers around my house making note of how easy they are to carry. If a model weighed more than 20 pounds or is hard to move in a tangible way, it lost points. Most units were easy to move and featured handles.
Long-term costs: Electricity and filter replacement are the biggest long-term costs. These can often outpace the upfront costs. I looked at how much a year's supply of filters costs and if they're widely available and not just on the manufacturer's website, which can make it hard to price shop. I also used a smart plug to measure the power consumption of each unit over the course of 24 hours under normal circumstances on the same setting I used for the purifying tests.
Noise: An air purifier's operation should not get in the way of hearing the TV, sleeping, or having a conversation. To test this, I used a sound meter to measure the air purifiers on their highest and lowest settings from four feet away. On low, most units were indistinguishable from ambient noise.
Maintenance: I cleaned each air purifier per the manufacturers' recommendations and noted how easy each model was to clean. I also noted whether there were indicators to let me know when to clean or replace the filter.
What we're testing next
We have new air purifier models arriving on a weekly basis to ensure our guide is as complete and accurate as possible. For our next update, we are looking forward to testing the following:
Dyson TP07 ($549.99): We're excited to test another new Dyson model after the disappointing performance of the HP09. This is another unit that does more than just purify, cooling rooms up to 800 square feet in size. It also has smart connectivity so you can control it and monitor your air quality from anywhere.
Blueair DustMagnet 5410i ($369.99): Full disclosure, we've had this purifier on hand since January, tested it, and were ready to include it in our guide when Blueair informed us that it won't be launched until fall 2021. Count on seeing this as one of our top picks in future iterations of this guide.
Coway Airmega 250 ($399.00): This is another model we tested that isn't available yet. It's supposed to launch this month. We're not sure if it will be tops in any of our categories, but it performed better than some of the units we recommend.
NuWave OxyPure ($599.99): NuWave is perhaps best known for its air fryers. This smart air purifier is the company's first non-kitchen appliance. We're curious to see how well the five-filter system works.
Room Air Purifier by Carrier ($355): Best known for its central air conditioning, Carrier is seeing if its HVAC prowess translates to room air purifiers. This model has an auto mode and is purportedly able to clean the air in a room of up to 400 square feet in 15 minutes.
Why do I need an air purifier?
Air purifiers can help clean indoor air of pollen, pet dander, incense, cooking grease and smoke, and more — basically, it does what its name implies.
According to the EPA, air purifiers outfitted with a HEPA filter are an effective way to remove particles from smoke and ash and can be particularly helpful in improving symptoms for individuals with asthma or COPD. They are also an effective way to improve indoor air quality during wildfires (as we saw during 2020's spat of fires on the West Coast).
What do air purifiers remove from the air?
An air purifier's filter will determine what pollutants it can remove from the air. A HEPA filter removes particulate matter ranging from 0.3 to 10 microns. This includes bacteria, mold, pollen, dust, smoke, pet dander, and more.
Activated carbon filters and other specialized filters can remove gases, including VOCs, from the air. These gases are often produced by consumer products, paints, industrial solvents, refrigerants, cosmetics, pharmaceuticals, fuel, pesticides, cleaning supplies, and more. Unlike HEPA filters, there is no standard for measuring the effectiveness of gas-removing filters.
What does HEPA mean?
HEPA stands for "high-efficiency particulate air." As defined by the EPA, true HEPA filters are able to capture at least 99.97% of all airborne particles, including dust, mold, bacteria, and pollen, that are 0.3 microns in diameter.
Are all your picks true HEPA filters?
No. That said, we generally give true HEPA filter models preference in our picks. However, there are some "HEPA type" or even non-HEPA models that perform just as well or better than true HEPA filter models and have features that make them a better pick. We make a point of specifically saying if a model has a true HEPA filter.
What's the difference between true HEPA and HEPA-type filters?
As mentioned above, a true HEPA filter can capture at least 99.97% of all airborne particles that are 0.3 microns in diameter, which the EPA calls the most penetrating particle size, meaning particles that are larger or smaller should theoretically be easier for true HEPA filters to catch.
HEPA-type filters do not have a standard so it's important to look for the "true HEPA" language to ensure you're getting an effective filter.
Can an air purifier prevent the spread of the novel coronavirus?
If you're considering an air purifier to help protect against the novel coronavirus, according to the EPA, a portable air cleaner by itself is not enough. However, when used along with other best practices recommended by the Centers for Disease Control and Prevention such as hand washing and social distancing, running an air cleaner can be part of a plan to protect you and your household.
Can HEPA or H13 purifiers capture viruses, including the coronavirus?
HEPA air purifiers help with the coronavirus but won't completely eliminate it, says Ravi Pandey, MD, an internal medicine specialist in South Florida. He adds that the virus is smaller than what air purifiers generally capture. Most viruses, including the coronavirus, are 0.06 to 0.12 microns. HEPA filters are designed to filter out at least 99.97% of airborne particles 0.3 microns in size.
However, while an air purifier alone isn't enough, it can be another tool for protection when used in conjunction with social distancing, hand washing, and mask wearing.
What can you do to get the most out of your air purifier?
"To maximize efficiency of your air purifier, make sure the system is constantly running," says Bryan Buckley, the brand manager for One Hour Heating & Air Conditioning. "Turning the system off doesn't allow for continuous air circulation, which impacts air purification. Keep the air purifier running at all times for best results."
Another best practice is to keep the air purifier confined to one room, said Buckley. "While these systems are portable, if you're constantly moving the purifier from room to room, you aren't maintaining a consistent level of air quality. The room you started purifying initially will start to become more polluted once you relocate the air purifier to another area, so it's recommended to keep the system stationary," he said.
Where do you put an air purifier?
You'll likely want an air purifier in your bedroom, living room, or kitchen — these are common areas that get a lot of traffic, and in the case of your kitchen, might help remove smoke from cooking.
"Wherever you decide to place the air purifier, always position the system so the clean air is blowing towards where people gather," says Buckley. "Don't point the system toward the wall, as it's best directed to an open space. Additionally, its best to keep doors and windows closed while the purifier is on to prevent new pollutants from entering the home."
How often do you change the filter?
This depends on the manufacturer's guidelines — some suggest every three months while others say every two years. We give you the recommended replacement schedule for each of the models in our guide.
"Replacing your air purifier filters, as recommended by the manufacturer, will help to maximize the system's efficiency," says Buckley.
Can plants help clean indoor air?
Think again before filling your house with plants. A 2019 study published in the Journal of Exposure Science & Environmental Epidemiology shows that indoor vegetation will not remove significant pollutants from the air.
How can you keep your air clean if you don't have an air purifier?
Intense wildfires that raged in California and Oregon in 2020 burned more than 3 million acres, displaced hundreds of thousands of people, and blanketed cities hundreds of miles away from the epicenters in ash and eerie orange skies. Between wildfires and the novel coronavirus, air quality was at the forefront of many minds.
When so many people are struggling with poor indoor air quality, air purifiers tend to go out of stock quickly. We spoke with Junfeng Zhang, PhD, professor of global and environmental health at Duke University, for advice on what you can do if you don't have an air purifier.
Dr. Zhang is particularly concerned about how individuals with asthma, COPD, heart disease, and other pre-existing diseases cope with poor air quality. "In the absence of a HEPA-based air purifier," he said, "I'd suggest that people, especially those who are more susceptible/vulnerable, wear N95 face masks, even when staying indoors."
Unfortunately, true N95 masks are still hard to come by and should be reserved for medical workers but there are some more widely-available alternatives, such as KN95 masks, which can provide a decent level of filtration. The CDC has released respirator assessment results for some of these. There is a lot of misinformation and counterfeit products floating around, so be extra cautious in ensuring that you're buying from a trusted seller.
If you're one of the lucky ones who has an air purifier when wildfire season hits, remember to clean your filter thoroughly and often so it can do its job. But for an effective multi-pronged attack on pollutants, you'll want to test and improve your air. Here's how to test and improve indoor quality and a few steps you can take to clean your air more effectively:
- Clean regularly: Irritants can collect on surfaces and cause sneezing fits when disturbed. When you clean regularly — including dusting and vacuuming — you remove allergens and more. Check out our guides for the best vacuum cleaners, best robot vacuums, best budget vacuums, and best cordless vacuums.
- Ventilate: This could include installing ventilation fans in your bathroom or kitchen, or running (well-cleaned) ceiling fans. Freestanding fans can also help clean air circulating, here are the best ones. Be sure not to open windows or doors to prevent polluted air from coming inside.
- Store chemicals outside of your house: Abrasive cleaners and other harsh chemicals are often a source of irritation. Store them in your shed or garage and not where you will be exposed to them regularly.
Are ionizing air purifiers safe?
There is debate over the safety and efficacy of ionizers. This type of purifier uses ionization technology to send out negatively charged ions that move through the air and stick to surfaces in the home such as the ceiling, windows, and floor.
"The research suggests that these particles prevent the growth of [some] infectious mold and bacteria, which is why they're commonly used in sterile environments like hospitals and dental clinics," said Buckley. "The reason they are controversial for home use is because they don't actually get rid of existing pollutants in the home. Instead, they stick to surfaces, including the inside of our windpipes and can irritate our airways over time by producing ozone that builds up indoors."
"However, it's worth noting most ionizing purifiers produce a very minimal amount of ozone," added Buckley. "And, the amount produced is usually so minimal that it only tends to irritate asthmatics and others with respiratory issues."
Dr. Pandey seconded these same pros and the cons.
For these reasons, we think that the negatives of ionizers outweigh any potential benefits.
In this guide, we throw around a lot of terms you may not be familiar with. Here are a few definitions of terms and acronyms that are commonly used when talking about air purifiers:
ACPH/ACH: This stands for "air changes per hour" Most experts recommend choosing an air purifier that can achieve three to five ACPH in the room you choose. In our guide, we give recommended room sizes based on four ACPH.
CADR: Clean air delivery rate. Typically measured in cubic feet per minute or cubic meters per hour, the CADR tells you how much air an air purifier can clean.
cfm: Cubic feet per minute. This is the most common unit of measurement used to express how much air an air purifier can clean.
HEPA: High-efficiency particulate air. True HEPA or HEPA-type filters are generally considered to be the gold-standard in the industry. For more details, see our FAQ section.
VOCs: Volatile organic compounds. These compounds have low water solubility and high vapor pressure. They are commonly produced in the manufacturing of refrigerants, pharmaceuticals, and paints and are often found in paints, craft materials, adhesives, markers, furniture, pesticides, cleaning supplies, and more.
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