Smart air purifiers can help you keep a close eye on your indoor air quality and breathe a little easier. From HEPA filtration to ionic technology, we help you understand your options and select the best connected air purifier for your needs and budget.

Between allergies, COVID-19, and wildfires, there are plenty of reasons to be concerned about the quality of the air you breathe. With these issues more prominent than ever, it's no wonder that demand for air purifiers is on the rise(Opens in a new window) . 

A high-quality air purifier can remove bacteria, dust, industrial emissions, mold, odor, pet dander, pollen, viruses, and other contaminants from the air. But not all air purifiers are created equal, and with so many compelling models on the market, it can be tough to narrow down your options. Over the past year, we here at PCMag have made it a priority to test a wide range of smart air purifiers to help you select the best one for your needs and budget. 

On a personal note, my interest in air purifiers began in pre-COVID times, shortly after I adopted my pitbull Bradley in the fall of 2019. I'm allergic to dogs, but his cute face and playful personality easily won me over. It wasn't long after adopting him that my allergies turned into asthma. Desperate for relief, I bought a refurbished Dyson Pure Cool Link TP02 on eBay during a Black Friday sale. My refurbished unit worked like new, and while I can't say that it alone cured my asthma and allergies, it has helped lessen my symptoms (along with medicine and daily vacuuming). 

Since then, I've acquired an army of smart air purifiers from various brands to test and review. I still take Xyzal allergy medication daily, but haven't had an asthma flare-up or had to use my Albuterol inhaler in more than a year. I tell you this as a testament to the power air purifiers (as well as robot vacuums and modern medicine). 

If you're looking to improve your indoor air quality, a good purifier is a must. But before investing in one, read on for some important factors to consider. 

Most air purifiers (not just smart ones) typically have sensors that measure the density of various airborne pollutants such as nitrogen dioxide (NO2, a toxic gas primarily produced by car exhausts and power plants), PM2.5 (particulate matter smaller than 2.5 microns in size, including industrial emissions and tobacco smoke), PM10 (particulate matter up to 10 microns, including dust, mold, and pollen), and VOC (volatile organic compounds, or potentially harmful gases from things like cleaning products and paint). 

Smart air purifiers typically feature Wi-Fi for phone and/or voice control, and to collect information on the pollutants above, sending it to a companion app where you can monitor your home's air quality. Some apps offer graphs of your air quality over time. Dyson breaks it down by pollutant, showing graphs for each one. 

Most smart air purifiers feature an auto mode, which will automatically adjust the machine's fan speed based on the level of pollution detected. They also typically let you set up an air purifying schedule, so the machine automatically turns on and off at your specified times. Some models feature Amazon Alexa, Google Assistant, and Apple Siri support, so you can control them with voice commands. 

If a smart air purifier is out of your budget, the $69.99 Amazon Smart Air Quality Monitor, which tracks airborne pollution levels around the clock, can be paired with a traditional air purifier as a more affordable alternative.

Some sources of indoor air pollution are obvious, like cigarette smoke, household cleaning products, and pet dander. Others are less so. 

The US Environmental Protection Agency (EPA) says(Opens in a new window) that "thousands" of products—including air fresheners, dry-cleaned clothing, and office equipment like copiers and printers—emit VOCs, which can lead to a long list of health effects ranging from headaches to cancer. Moreover, concentrations of VOCs are typically much higher indoors than outdoors. 

Anything that causes smoke—such as cooking, burning candles or incense, or lighting up a fireplace—can lead to elevated concentrations of particulate matter. The EPA says(Opens in a new window) PM10 and smaller can "get deep into your lungs" and, in some cases, your bloodstream. Inhalable particles, especially PM2.5, which is 30 times smaller than the average human hair, may pose a greater risk to those with heart and lung diseases such as asthma, chronic obstructive pulmonary disease (COPD), congestive heart failure, and coronary artery disease. Most smart air purifiers detect PM10 and PM2.5, but LG's $1,299 PuriCare 360 is the only model on this list that reports the density of PM1.0 (particulate matter 1 micron or smaller). 

Humidifiers can help relieve cracked lips and dry skin, but if you’re not careful to use distilled water and clean them often, they can provide a fertile breeding ground for bacteria and mold, which is then pumped into your air. Gas stoves, especially when not properly vented, can emit unsafe levels of NO2(Opens in a new window) , which can irritate the respiratory system and exacerbate or contribute to the development of asthma. 

Another gas pollutant to worry about, especially if you're renovating or redecorating your home, is formaldehyde, which is released by many household items such as carpets, flooring, furniture, rugs, insulating materials, particleboard, plywood, paint, varnishes, and wallpapers. Long-term exposure to low levels of formaldehyde can cause skin, eye, nose, and throat irritation. Higher levels can cause some types of cancer. 

Dyson says that formaldehyde is 500 times smaller than 0.1 microns, making it difficult to capture. Not all air purifiers can detect and break down formaldehyde (Dyson charges $100 more for models that do), so that's something to consider when mulling your options. Check out our individual reviews to see which contaminants each model detects and captures. 

In some cases, exposure to airborne pollutants may not cause immediate symptoms, but can lead to serious health problems down the road. For this reason, the EPA says(Opens in a new window) , "it is prudent to try to improve the indoor air quality in your home even if symptoms are not noticeable."

Buying an air purifier isn't the only way to improve your indoor air quality. Other steps(Opens in a new window) you can take include eliminating the sources of your air pollution, opening a window (as long as the outdoor air quality is good), and regularly vacuuming and dusting surfaces. 

The machines on this list combat airborne contaminants using High Efficiency Particulate Air (HEPA) filters, activated carbon filters, ionic technology, and/or UV light. 

HEPA air purifiers are the most popular(Opens in a new window) , making up the largest segment of the market. To comply with the current baseline standard(Opens in a new window) , HEPA filters are tested and certified to remove at least 99.97% of dust, pollen, mold, bacteria, and any other airborne particles as small as 0.3 microns. There are different levels of HEPA filters, but in general, you want to make sure the model you buy meets the baseline standard (many that do are labeled "True HEPA") and stay away from those marketed as "HEPA-like," "HEPA-type," or "HEPA-style," which may not be as effective. 

As Wirecutter(Opens in a new window) reported in 2020, a NASA study found that HEPA filters can actually capture almost 100% of particles as small as 0.01 microns (10 nanometers), well exceeding the baseline standard. To put that in perspective, COVID-19 is about 60 to 140 nanometers(Opens in a new window) . H1N1 influenza is about 80 to 120 nanometers(Opens in a new window) . 

Meanwhile, activated carbon filters are filled with porous carbon, which traps gases such as NO2 and VOCs, as well as foul smells, from the air. Activated carbon filters are often combined with HEPA filters, which do not remove gases.

Our top overall choice, the $549.99 Dyson Purifier Cool TP07, features a 360-degree filter with a HEPA layer that captures allergens, bacteria, mold spores, pollen, and other pollutants, and an activated carbon layer that removes gases and odors. It also doubles as an oscillating fan. The version that destroys formaldehyde, called the Purifier Cool Formaldehyde TP09, costs $649.99. Dyson says its latest air purifiers, including the TP07 and TP09, not only meet the baseline HEPA filter standard, but are also fully sealed to the HEPA H13 standard(Opens in a new window) , meaning they can remove 99.95% of particles down to 0.1 microns.

The LG PuriCare 360 is another model that combines HEPA and active carbon. The only downside to HEPA and active carbon models is that the replacement filters can be costly (around $50 to $100) and wasteful.  

Other models, like the Sharp FXJ80UW and Aura Air, combine HEPA, active carbon, and ionic technologies. Sharp's model features an ion-generating unit that creates positively and negatively charged ions using water and oxygen molecules in the air, and disperses them throughout the room. The ions then actively attach to and break down airborne pollutants like bacteria, mold, and viruses before returning to the air as invisible water vapor. Sharp says the technology reduced 94% of E.coli bacteria, up to 87.7% of mold fungus, and 90.3% of MS2 virus in a closed laboratory over four hours. Aura Air's patented Sterionizer disinfection technique works in a similar way. 

The primary concern about ionic air purifiers is their possible production of ozone gas molecules, a lung irritant that can exacerbate asthma symptoms and cause a host of other health issues(Opens in a new window) . The safety of ionic air purifiers came into question in the mid 2000s(Opens in a new window) , after it was revealed that the then-popular Sharper Image Ionic Breeze air purifier produced ozone (an issue that eventually bankrupted the company(Opens in a new window) ). 

As the California Air Resources Board (CARB) warns, some ozone-producing devices are still marketed as air purifiers. The clean air agency maintains a list of potentially hazardous models(Opens in a new window) to steer clear of. 

All models on our list that use ionic technology are EPA-compliant, CARB-certified, and considered safe to use in your home for extended periods of time.

With the exception of Dyson, most smart air purifier makers tell you the maximum room size their machines can effectively clean. A Dyson spokesperson says the company's latest air purifiers are "engineered to purify all rooms—it's just a matter of how long it takes (the larger the room, the longer it will take for purified air to reach all corners)." That said, Dyson tests(Opens in a new window) its Pure Cool purifying fans to ensure they can circulate purified air throughout a 290 square-foot space (which is about the size of a large living room). 

The LG PuriCare 360, which features two large 360-degree HEPA filters, is recommended for rooms up to up to 512 square feet. LG says the PuriCare 360's fan can push purified air up to 24 feet away. Its lower section blows purified air 19 inches from the ground, which benefits babies and children.

The Sharp FXJ80UW, which is recommended for rooms up to 502 square feet, is another excellent option for large rooms. At one point while testing it, I accidentally burned toast, and the FXJ80UW sensed the smoke from a different room. Its air quality monitor light went red and the machine automatically increased its fan speed.

In my roughly 1,000 square-foot, single-level home, most of the smart air purifiers I've tested can detect elevated levels of air pollution even from several rooms away. Sometimes, when I'm frying veggies in the kitchen, the Dyson TP07 located across the house in my office will detect cooking smoke I didn't even notice, automatically kicking on. 

Whether air purifiers can truly reduce allergies caused by larger particulates such as pollen, dust, mold, and animal dander is a bit controversial, according to the EPA. 

"Most of these particles are found where they settle on surfaces in the home, rather than in the air," the EPA says. "They cannot be removed by an air cleaner unless disturbed and re-suspended in the air."

Before turning to an air purifier for allergy relief, consider what type of allergies you have. Air purifiers may do a better job of capturing pet dander compared to other types of allergens. According to the American Lung Association(Opens in a new window) , pet allergens "remain suspended in the air for a long time, much longer than allergens from cockroaches or dust mites." Dust mites(Opens in a new window) , on the other hand, "cling to particles that are too heavy to remain in the air for long" and settle into things like pillows, bedding, and furniture "within minutes." 

In my experience, air purifiers aren't an infallible cure for pet allergies, but they can certainly help. To combat dander from my dog, I usually keep at least one air purifier running 24/7. I find it particularly helpful to have one blowing clean air in my direction at night, when my symptoms often worsen. 

With my allergic asthma now under control, my doctor has given me the OK to discontinue my Montelukast prescription on a trial basis. I've been off of it for several months now, and haven't experienced any asthma. Needless to say, I'm a big fan of air purifiers and plan to continue using and testing new models for the foreseeable future. 

Going forward, I'll continue to update this list as we review new models we deem worthy of inclusion. In the meantime, let us know in the comments if there are any specific smart air purifiers you would like to see reviewed. 

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I'm PCMag's expert on fitness and smart home technology, and I've written more than 6,000 articles and reviews in the 10-plus years I've been here. I unbox, set up, test, and review a wide range of consumer tech products from my home in Florida, often with the help of my pitbull Bradley. I'm also a yoga instructor, and have been actively teaching group and private classes for nearly a decade. 

Before becoming an analyst in 2020, I spent eight years as a reporter covering consumer tech news. Prior to joining PCMag, I was a reporter for SC Magazine, focusing on hackers and computer security. I earned a BS in journalism from West Virginia University, and started my career writing for newspapers in New Jersey, Pennsylvania, and West Virginia.

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