Having An air quality monitor for your home is more important than you may think. As climate change speeds up and wildfires increasingly engulf large swaths of land, leaving behind smoke that makes air potentially hazardous to breathe, it's more important than ever to ensure you're breathing clean air. An at-home air quality monitor is a simple way to ensure that, whether it be car exhaust, wildfire smoke, pollutants from seasonal changes, or simply fumes from your gas stove, the air around you is safe to breathe.
These air quality monitors test the air quality both indoors and outdoors, and on top of measuring PM2.5 (particulate matter) in the air and AQI (air quality index), they can also give insights into the air you're breathing, including measuring temperature, humidity, CO2, VOCs, and more.
Our top pick, IQAir's Air Visual Pro ($330), measures for several factors and has an easy-to-read display, while our more basic budget pick, Temptop S1 PM2.5 Air Quality Monitor & Indoor Thermometer ($28), has been solid throughout prolonged testing.
For more ways to keep your air quality in check for a healthier environment, take a look at our guides to the Best Outdoor Air Quality Monitors, Best Air Purifiers, and Best Multiuse Air Purifiers. Plus, check out how we test them and how to pick the right air purifier for your home.
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Best Indoor Air Quality Monitor
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The AirVisual air quality monitor has an easy-read 5-inch LCD display screen and a graphic of a boy’s face along with the AQI color scale that lets me know my indoor air quality from across the room. As the air quality gets poorer, the little boy will stop smiling with a green background and become solemn with a yellow background; finally, if the air is truly dangerous, he’ll put on a gas mask and the color turns dark purple. I like that I don’t have to log on to the internet or open an app to know if I have clean air. Plus, the AirVisual has the added feature of giving both indoor and outdoor air quality data. This saves me the extra step of checking the outdoor air quality on my phone. And it cycles through various displays—it has the time, then it will show both indoor and outdoor readings, along with congratulating me for achieving excellent indoor air quality or it will recommend that I open a window. The AirVisual air quality monitor measures PM2.5 and CO2 and displays the temperature and humidity. It has an easy-to-read dashboard on the app and keeps data for a year, but its biggest strength is its display, especially when I burn a pizza and the boy gets sad and dons a gas mask. —Lisa Wood Shapiro
| App | Yes |
| Crowdsourced AQI map | No |
| Indoor | Yes |
| Outdoor | No |
| Pair with air purifier | No |
Best Dual Indoor-Outdoor Air Quality Monitor
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The Zen air quality monitor uses the EPA AQI color scale: green for good air, yellow for moderate, orange for unhealthy for sensitive groups, red for unhealthy, purple for very unhealthy, and deep violet/maroon for hazardous. The colored glow’s intensity can be controlled by the number of taps of your finger and can be mounted onto a pole or wall or can be placed on its circular stand. Each Zen air quality monitor can be linked to the crowdsourced PurpleAir’s Real-Time Air Quality Map. Linking the Zen is optional, but to see the actual Air Quality Index number that the Zen is reading, I had to link my specific monitor with its unique ID code to the PurpleAir website. There’s an option to have the monitor be public or private; by clicking public, you get to contribute as a citizen scientist to the Real-Time Air Quality Map. I was surprised to see just how many PurpleAir monitors there are in New York City, not to mention Brooklyn. It gave an accurate close-up of my block and my neighborhood. In this current climate of extreme weather, the PurpleAir Real Time Map is especially useful. —Lisa Wood Shapiro
| App | No |
| Crowdsourced AQI map | Yes |
| Indoor | Yes |
| Outdoor | Yes |
| Pair with air purifier | No |
Best Cheap Air Quality Monitor
- Photograph: Molly Higgins
- Photograph: Molly Higgins
- Measures PM2.5, AQI, temperature, and humidity
- Battery lasts up to 60 days and uses a USB-C charger
- Can switch between two modes
- Screen can be dark and hard to read
- Readings can get stuck and machine needs a reset to accurately display
I've been testing air purifiers, measuring each unit’s efficacy by using a sealed tent and smoke pellets to see how quickly each air purifier clears the pellet smoke and returns the air to healthy quality when on auto mode. I time both visually when the air turns clear again and also measure with this little guy above for each test—comparing my results to the built-in AQI monitor numbers on the machines or their connected app to ensure that the measured levels (especially for PM2.5 and air quality) are correct. I'll be honest, this cheap monitor doesn't do everything that the more expensive models do, but it has worked for the simple tests I run.
This compact device measures and displays PM2.5, AQI, temperature, and humidity levels. It only measures PM2.5 particles and uses US EPA Standards to calculate the AQI. It doesn't measure for any other pollutants, so if you want a more comprehensive assessment with pollutants like CO2 or VOCs, you'd need another model. It has eco mode, which takes samples of the air every 30 minutes and lasts up to 60 days on a single charge; A mode, which samples air every three minutes and lasts about 20 days; and real-time mode, which samples air every 1.5 seconds for the most up-to-date and accurate current air quality readings—though it needs to be plugged (with a USB charger) in to work in this mode. This cheap device isn't perfect—it would get stuck in certain readings and not update, and I'd be forced to restart or plug in for accurate measurement. However, it's suitable for measuring indoor and outdoor environments and can operate within a range of -14 to 140 degrees Fahrenheit. If you just want a simple air quality monitor to gauge both indoor and outdoor pollutants, this model will do.
| App | No |
| Crowdsourced AQI map | No |
| Indoor | Yes |
| Outdoor | Yes |
| Pair with air purifier | No |
Best Indoor Air Quality Monitor With a Radon Sensor
Airthings' solid, unassuming minimalist design has an easy-to-read display screen, and it’s the first indoor air quality monitor I’ve tested that has a dedicated radon sensor. It also measures PM2.5, CO2, VOCs, temperature, humidity, and air pressure. And while the Airthings View Plus has an easy-to-use app, the monitor will not work without internet/Wi-Fi. It also needs time to calibrate. I saw radon, PM2.5, and humidity almost immediately, but the app told me I needed to wait days before the monitor calibrated the CO2 and VOC sensors. You'll also need to wave your hand in front of the device for an air quality check. The movement from my hand triggers the sensor to show any value above the recommended levels, along with the indicator light, which shows green for good, yellow for fair, and red for poor. The more I test air quality monitors, the more I appreciate those with color-coded indicator lights that I can see from across the room. I recommend Airthings because of its ability to measure everything from radon to PM2.5, and it also has backup batteries in case of a power outage. —Lisa Wood Shapiro
| App | Yes |
| Crowdsourced AQI map | No |
| Indoor | Yes |
| Outdoor | No |
| Pair with air purifier? | No |
Compare Our Picks
| App | Crowdsourced AQI map | Indoor | Outdoor | Pair With Air Purifier? | |
|---|---|---|---|---|---|
| IQAir AirVisual Pro Indoor Monitor | Yes | No | Yes | No | No |
| PurpleAir Zen | No | Yes | Yes | Yes | No |
| Temtop S1 PM2.5 Air Quality Monitor & Indoor Thermometer | No | No | Yes | Yes | No |
| Airthings View Plus | Yes | No | Yes | No | No |
How I Tested
In the past, I've relied on my phone's weather app to measure the air quality around me, and the government’s free AirNow website, where you can plug in your zip code and see its easy-to-read air quality meter. Now, as I test air purifiers, I always make sure to corroborate the purifiers' built-in PM2.5 or AQI measurements with an independent outside source—a separate air quality monitor—to test both the accuracy of the machine and the purifier's efficacy in filtering pollutants and getting the air quality back to a healthy level.
These air quality monitors were tested in various locations around my house, when cooking on my unventilated gas stove, under my living room window that draws in a lot of building and exhaust fumes, and outside my cat's litter box. Plus, I did additional testing outdoors, where I measured the monitors’ readings against local weather apps. And when field testing air purifiers with a sealed tent and smoke pellets as mentioned above, I always use an air quality monitor to check pollutant levels and the purifiers' efficacy when timed to get back to healthy levels.
Why Do I Need an Air Quality Monitor?
Like I mentioned above, I think it's especially important to have an air quality monitor to test whether your air both inside and outside the home is healthy if you don't have an air purifier. But it's also important to have one to measure the efficacy of the air purifier(s) in your home to ensure they are doing their job as efficiently as claimed. Especially since after prolonged use (and time), the built-in sensors can clog and give inaccurate readings.
When placing or installing an air quality monitor, try to measure at the breathing zone height, around 3 to 6 feet off the floor. An air quality monitor is especially helpful against some of the more harmful effects of things like wildfire smog, which can't always be smelled or seen. But an air quality monitor can sense that there is too much bad air, and then you can adjust the air purifier fan(s) accordingly.
It can also help to instill healthy habits, as WIRED Reviews contributor Lisa Wood Shapiro notes, using air quality monitors taught her to turn on the kitchen exhaust fan and crank up an air purifier before she turns on her gas stove. In the past, she didn’t think much of a little smoke from cooking. Now she takes proactive steps to avoid inhaling harmful pollutants.
Once you start noticing bad air and take steps to correct it, you'll notice fewer allergy symptoms and, often, fewer upper respiratory sicknesses and improved sleep. Even innocuous household things like lit candles, cooking on a stovetop without an exhaust fan (guilty), or aerosol air fresheners can negatively impact indoor air in real time. Get yourself an air quality monitor and see for yourself.
What to Consider Before Buying
Even though many current air purifier models have built-in air quality sensors, having a designated air quality monitor is a great way to independently corroborate or monitor air quality and pollutants. Plus, these handheld monitors are also portable and able to more accurately test air quality outdoors.
Before you purchase your own indoor air quality monitor, here are some things to know: Sensors on the WIRED-tested AirVisual Pro and PurpleAir all performed well in an independent study. Low-cost consumer air quality monitors are much cheaper (in the $200 or less range) than what's used by the professionals, but are also less accurate and not as easily calibrated. When testing multiple air quality monitors, they will not usually give the exact same AQI, but they are usually very close.
Consumer air quality monitors use sensors to detect tiny invisible particles in the air and other contaminants, with some sensors using light scattering to detect fine particulate matter known as PM10, like the dust visible in light, and invisible health hazards like PM2.5, which can reach the deepest parts of the lungs and enter the bloodstream.
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