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Indoor Air Quality Monitors
By Dr. Meg Christensen | Updated November 2025
The best indoor air quality monitors available, because they’re actually accurate.
Comprehensive Monitors
The Airthings View Plus is the best indoor air quality monitor overall because it tracks the most important things in your air including VOCs, PM 2.5, CO2 and radon, which sets it apart from many other options. Airthings is a RESET certified brand. It’s a portable air quality monitor that’s highly accurate and aesthetically pleasing. I have mine on the wall downstairs to keep an eye on radon, as well as smoke from cooking and wildfires. You can use code INTERIORMED-10OFF for 10% off through the Airthings website here, or you can check the price on Amazon here.
Wave Enhance
An air quality monitor to help improve your sleep. The Wave Enhance tracks light levels, noise levels, CO2, air pressure, temperature and humidity. It tells you what happened during the night so you can use the information to improve your sleep (and next-day mood and productivity.) You can get 10% off with the code INTERIORMED-10OFF at checkout through their website here. You can also check the price on Amazon here.
The Awair Element is an ultra-accurate air quality monitor for home. Like the Airthings, it’s also RESET certified, but is more affordable because it doesn’t track radon. It does monitor indoor VOCs, PM 2.5, CO2, temperature, and humidity, with an easy-to-read screen. I use this in my office upstairs, where radon isn’t a concern, but high carbon dioxide levels which make me sleepy are. You can see my video about how surprisingly fast CO2 builds up here, if you’re curious.
This multi-room system includes an indoor air quality monitor with radon, VOCs, and mold growth potential (humidity and temperature), reporting results continuously through the app. This is a good option if you’re not too worried about tracking PM 2.5 (wildfire smoke or cooking particles.) This kit is currently only available on Amazon.
Point-in-Time Air Testing Kits
The popular water-testing company MyTapScore also offers air quality testing for VOCs and formaldehyde. If you have a mystery smell in your home, or want to understand how much formaldehyde is present upon moving in to a new-build or buying new furniture, this is a great way to check. Laboratory analysis of an air sample is required to understand what specific VOCs are present— continuous monitors are notoriously bad at knowing if something is formaldehyde or not, and can’t sort out any specific VOCs. It can only tell you that there are a lot of them, or not very many. A great service.
Another option for doing detective work, Home Air Check also sells single-use monitors through Amazon and does laboratory analysis to determine what VOCs are present. They also check for actively growing mold, which can be helpful if you have symptoms.
Outdoor Air Quality Monitors
I keep the windows in my house open almost all of the time, but if I wake up and notice my indoor air quality monitor is showing high levels of PM2.5, I check the Purple Air real-time map right away to see what the outdoor air conditions are like. Although this website is focused on the indoors, it’s very helpful to know when it’s time to close the windows in case of wildfire or excessive air pollution days. You can get a monitor here to help track air conditions in your area.
Even if you don’t want to track anything else in your indoor air, you should track radon, the second most common cause of lung cancer that comes from invisible gas under the foundation of your home. The fix is easy; just test your home to know it’s there. Here are the four I recommend.
Basic Indoor Air Quality Monitors
Wildfire Smoke Monitor
This is the best air quality monitor for wildfire smoke. It’s the only Temtop brand product I recommend, because it doesn’t have a gimmicky formaldehdye sensor (which don’t work in the residential low-cost level of monitors) and it does almost as well measuring PM 2.5 as scientific-grade air quality measuring instruments (it gets a high 0.91 score on AQ-SPEC; read more below). It’s not as accurate at measuring PM10 (big particles like pollen) and it doesn’t measure VOCs, but it gives you a super-accurate PM 2.5 reading, one of the primary concerns of wildfire smoke.
If you just need to avoid mold, a hygrometer will track humidity levels for you. Mold grows best above 60% humidity, so this can help keep you informed about your home’s levels. This is a simple and inexpensive air quality monitor for mold so you can aim for between 40-50% humidity— a good range so that you’re still comfortable, but mold isn’t.
More Healthy Design for You
Your Complete Guide to Indoor Air Quality Monitors
What pollutants do indoor air quality monitors measure?
Continuous, comprehensive Indoor Air Quality Monitors typically measure the four most common indoor air pollutants, as well as temperature and humidity, and radon:
PM2.5 (Particulate Matter): includes fine particles from smoke, dust, and outdoor pollution that can penetrate deep into your lungs and bloodstream, contributing to heart disease and asthma.
CO2 (Carbon dioxide): builds up in poorly ventilated spaces and causes headaches, fatigue, and reduced concentration—high levels also indicate your room isn't getting enough fresh air.
VOCs (Volatile Organic Compounds): gases released from cleaning products, furniture, paints, and building materials that can trigger respiratory symptoms. This is measured as total VOCs (TVOCs)— home-use indoor air quality monitors cannot measure individual types of VOCs, like formaldehyde for example.
Radon: the leading cause of lung cancer in non-smokers.
Temperature
Humidity: high humidity promotes mold growth
Some indoor air quality monitors are even broader:
The Awair Omni tracks most of the data above, plus PM10 (large particle), sound levels in decibels, and light levels — but it’s generally only available for businesses.
Some air quality monitors are more focused:
Radon Detectors measure radon only.
Hygrometers measure humidity only.
Carbon monoxide (CO) detectors measure carbon monoxide only.
Non-continuous, point-in-time air quality testing can catpure a broad range of information, potentially measuring hundreds of types of VOCs, but the sample is focused on a short period of time. The air sample must be sent in and analyzed in a laboratory.
Do air quality monitors measure formaldehyde?
No, home-use indoor air quality monitors are not capable of distinguishing formaldehyde from other VOCs. While it is possible to measure formaldehyde using very advanced, expensive, laboratory-grade equipment, residential monitors claiming they can measure formaldehyde separately are overstating their abilities—and this is a red flag about the monitor's overall credibility.
You can see this for yourself in YouTube videos where people open a beer or peel an orange close to a "formaldehyde sensor," and the numbers go off the charts. This is a false reading. The sensor is simply detecting VOCs from the beer or citrus oils, not formaldehyde itself (which isn't present in beer or oranges). The monitor can't tell the difference.
Brands that skip this gimmick are more likely committed to providing you with accurate, honest data about your indoor air quality. (Sorry, Dyson.)
Are the air quality sensors on air purifiers accurate?
Short answer: No, the built-in air quality sensors on most air purifiers only give you a loose approximation of your actual air quality, not precise readings you can trust.
There are two main reasons why air purifier sensors aren't reliable:
1. Air purifier sensors use cheaper, less accurate technology. Making an accurate indoor air quality monitor is difficult and expensive—the most reliable standalone home monitors cost $100-600. Most air purifiers use basic infrared PM2.5 sensors that are inexpensive to manufacture but provide only rough estimates. It would significantly increase the cost of an air purifier to include a truly accurate sensor, so manufacturers typically use budget components that give you a general idea rather than precise data.
2. Air purifier sensors measure the wrong location. The sensor is built into the air purifier itself, which means it's measuring the air quality immediately around the device—air that has just been cleaned. This doesn't reflect the actual air quality across the room where you're sitting, which is what you really need to know. The purifier might show "good" air quality while the air on the other side of your room remains polluted.
What to do instead: If you want accurate air quality readings, invest in a separate, dedicated indoor air quality monitor and place it away from your air purifier—ideally where you spend the most time. Use the purifier's built-in sensor as a rough guide for when to change filters, but rely on your standalone monitor for real data about whether your air purifier is actually improving the air you breathe.
This approach costs more upfront but gives you the objective information you need to know if your air purification strategy is actually working.
Why use an indoor air quality monitor?
There are three main reasons to use an indoor air quality monitor:
1. They can literally save your life. (No big deal!) Indoor air quality monitors can detect radon, and alert you to high PM 2.5 levels.
Radon is a colorless, odorless radioactive gas that's the leading cause of lung cancer in non-smokers. It seeps into your home through from the radon-containing bedrock under your foundation, and you have no way of knowing it's there without testing. An air quality monitor with radon detection gives you continuous readings so you can catch dangerous levels early and take action.
PM 2.5 (Particulate Matter smaller than 2.5 microns) comes from every day cooking, wildfire smoke, and outdoor pollution that infiltrates your home. These tiny particles are so small they are able to travel deep into your lungs and enter your bloodstream. Because the blood takes them all throughout your body, PM 2.5 is linked with many kinds of diseases, including heart disease, stroke, lung cancer, and premature death. When you can see PM 2.5 levels spike on your monitor, you know exactly when to close windows, turn on your air purifier, or turn up your exhaust fan.
2. They can make your daily symptoms better. Indoor air quality monitors track indoor VOCs and CO2, as well as the humidity levels that contribute to a mold-friendly environment.
VOCs (volatile organic compounds) are gases like formaldehyde and many, many others that are released from everyday items like cleaning products, air fresheners, new furniture, paint, and scented candles. They often smell, but not always, and if they accumulate in your indoor air, they can trigger headaches, dizziness, eye and throat irritation, and worsen asthma symptoms. Some VOCs are also linked to long-term health effects. Your monitor helps you identify which products or activities cause spikes, so you can ventilate, turn your air purifier on, and start to understand patterns.
CO2 (carbon dioxide)builds up surprisingly fast in closed spaces—especially in your bedroom at night, in your home office during the day, and especially when a large group of people is all in the same room. While CO2 itself isn't toxic at typical indoor levels, concentrations above 1,000 ppm cause fatigue, difficulty concentrating, headaches, and that stuffy, drowsy feeling you get in poorly ventilated rooms. When you watch your monitor and see CO2 climbing, then crack a window and watch it drop, you'll immediately understand why you feel so much more alert and energized with proper ventilation.
Humidity: mold grows best in humid environments. An indoor air quality monitor is an objective way to let you know if you’re over-doing it with a humidifier, or if your house tends toward more moisture, and you investing in a dehumidifier is a good idea. Preventing mold growth can reduce allergies, mold toxicity symptoms, and protect you and your home’s long-term health.
3. They take the guesswork out of air purification and ventilation, reduce energy costs (and arguments with your partner ;). Knowing when to turn up your air purifier or open a window—even when it's cold outside—is just as useful as knowing when your indoor air is healthy and you can relax.
Without a monitor, there are lots of questions: Is your air purifier actually doing anything? Should you open windows during wildfire season? Is that new rug off-gassing chemicals? Is it smoky in my kitchen after cooking? An air quality monitor gives you objective data that answers these questions in real-time.
An air quality monitor helps you make smart decisions about when ventilation is worth the energy cost, when to run your purifier on high, and—just as importantly—when your air is clean enough that you can stop worrying and simply enjoy your home.
Reduces arguments with your partner, spouse, or roommate: I used to over-ventilate, leaving my house very fresh, but my husband very cold and our heating bill high. Now we can use our indoor air quality monitor as an objective measure— everyone is happier!
What's a good air quality score on my monitor?
Most smart monitors will color-code readings for you: green means good, yellow means moderate, red means poor.
But, if you’re interested in more details, here are general guidelines for optimal levels you should aim for indoors:
Radon: below 4.0pCi/L
PM2.5: below 9g/m3
VOCs: below 400ppm
CO2: below 600ppm
Humidity: 30-50%
These are based on RESET guidelines, which set standards for commercial building air, the EPA’s radon guidance, and the WHO (World Health Organization) guidelines for outdoor air. The EPA recommends PM2.5 should be below 9g/m3, but it’s interesting to note that the WHO is aiming to decrease the standard to 5g/m3 to decrease disease and death worldwide. I use these values because there isn’t an official set of residential indoor air guidelines yet.
A note: these values are surprisingly hard to achieve in any given moment, so it’s important to use your monitor to get average values and understand patterns over time — days, months, and years. Notice what causes air quality to deteriorate and improve. For example, when I cook on the stove, my PM 2.5 skyrockets to over 200 sometimes (watch my video of this happening here), and when I do yoga inside, my CO2 easily jumps over 1,000 (see the video of this happening here). But, the levels drop quickly with proper ventilation, and my averages are within guidelines.
In short, a continuous indoor air quality monitor is best for identifying patterns and averages for healthier home air over time.
How accurate are indoor air quality monitors?
Air quality monitor accuracy varies wildly by brand, and low-cost home monitors are often very inaccurate. The most accurate multi-pollutant monitors typically score above 0.9 on AQ-SPEC tests and cost $150-600.
Indoor air quality monitors operate on an invisible level, so it’s important to know they’re doing the job correctly and not giving you false readings. Look for the following:
RESET certification: brands that offer commercial models in addition to residential ones, can be RESET certified, ensuring accuracy
NRPP approval: for radon monitors
AQ-SPEC: This database compares low cost residential air quality monitors to the super-accurate, super-expensive air quality monitors used by scientists, to see how closely their readings match. The scores range from 0 to 1.0. A score of 0 means they don’t agree at all. A score of 1.0 means they agree perfectly. A score of 0.5 means they agree about half of the time. Choosing an air quality monitor with a score as close to 1.0 is ideal. It’s interesting to see how inaccurate some of the models are. One of the cons of this list is that it hasn’t tested all available models, and most of the ones it has tested with good readings are still very expensive in the $600+ range (Air Quality Egg), discontinued (Kaiterra Laser Egg), or difficult to use in a home. I expect this will continue to change as the need for in-home air quality monitoring continues to rise.
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