The Best Indoor Air Quality Monitors We’ve Tried

When that apocalyptic orange cloud set over San Francisco in 2020, the crowdsourced air quality index map PurpleAir was the place to see how bad the air really was. PurpleAir’s Real-Time Air Quality Map is created by the public using sensors that PurpleAir sells. It offers two types of outdoor air monitors: the PurpleAir Classic Air Quality Monitor and the PurpleAir Classic SD Edition, which is able to store data without Wi-Fi. The one I have is PurpleAir's new Touch Indoor Air Quality Monitor. Its simple white oval plastic orb reminds me of a decorative, color-changing night light. The PurpleAir Touch measures PM 2.5. If an air quality monitor can measure only one thing, it should be PM 2.5. PurpleAir uses the same color scale for the US Air Quality Index, or AQI Scale. The Touch’s inner LED ring glows 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. Depending on the number of taps of your finger, the glow gets brighter or turns off; it’s adjustable.

PurpleAir told me an app is in the works, but for the moment it's the PurpleAir website that has its “community scientist”-sourced map. I was confused the first time I looked at PurpleAir’s map, because it included both indoor and outdoor monitors. And while there the specific model of monitor pops up when you click the number, I’m not sure if I care that Zoe’s indoor air quality in Brooklyn is awesome or that Zander must have burned his muffins in Queens. I think including the indoor monitor data on the map muddies the user experience. To find out the actual AQI number that the PurpleAir Touch is reading, you need to register your Touch with PurpleAir and view it through PurpleAir's web portal. On its Real-Time PurpleAir Map I can see the circle that’s my Touch. There I can see the numbers for my living room. You can choose to be private or public. Looking at the map, I now want to get PurpleAir's outdoor monitor. And while configuring, registering, and checking a web portal is an extra step, I appreciate the simplicity of the Touch’s color system. The PurpleAir touch also makes a useful night light, though it was too bright for me at its highest setting.

At under $40, the Govee Smart Air Quality Monitor is one of the cheapest models I’ve tested. Govee has an easy-to-use and -pair app that can be further paired with Govee air purifiers, and an easy-to-read screen displaying the PM 2.5 along with temperature and humidity. I’ve been using the Govee Smart Air Quality Monitor for the past five months, and it likes to hang out at zero PM 2.5 much more than my other monitors. That said, I’ve moved it all around my home and its sensors spike when I’m cooking or using the toaster; it is just less sensitive than other far more expensive models. And even though it isn’t reading every piece of particulate matter flowing through the air, there’s a lot to be said for an affordable air quality sensor.

The Govee Smart is the size of a hotdog on a roll and comes in white or black. It has the option of displaying a digital clock (in military time) instead of the PM 2.5 reading, but I used it exclusively as an air quality monitor. The Govee Smart also has an air quality indicator color bar on the display; green for good, a confusing blue for moderate, then yellow, and red indicates bad air. If you’re an air quality monitor rookie, the Govee Smart might be the gateway air quality tool you’ve been seeking. I suggest placing your monitor outside your kitchen door or at least near your kitchen, always at breathing height—so at least 3 feet from the floor. Monitoring your PM 2.5 will give you a good idea if your cooking fumes are being pulled outside via exhaust or if they're wafting into your living space. And once you see your air quality, you can’t unsee it.

At under $50 and the size of a juice box, Ikea’s Vindstyrka packs a lot of features in a small package at a low price. The air quality monitor can be used on its own, paired with Ikea’s Starkvind air purifier, and/or connected to Ikea’s Home smart app via the Dirigera hub. I was curious about the Vindstyrka back when I reviewed the Starkvind air purifier. And while I liked the modern look of the purifier, it was on the small side, and the only way I could connect it with my phone was to also use Ikea’s smart home hub. Still, like the Govee Smart Air Monitor above, an inexpensive air quality monitor is a great option for those who don’t want to spend hundreds of dollars.

Unlike the PurpleAir’s bold and colorful—though more expensive—monitors, the Vindstyrka has a demure, almost hard-to-read display. It’s easier to see when the button on the top turns on the light illuminating the display, but I have trouble reading the monitor if I’m across the room. It isn’t a font issue; instead, the difficulty lies with Vindstyrka’s matte gray early-version-of-Kindle screen. Ironically, the Vindstyrka is easiest to read in low light, as it auto-illuminates its display screen. Still, for the price, the Vindstyrka does more than monitor PM 2.5, temperature, and humidity. It also tracks VOCs or volatile organic compounds, those vapors and gases that can cause a host of health issues. And while the Vindstyrka display screen uses an arrow to indicate if VOCs are rising, falling, or remaining the same, it’s some indication. Though to take full advantage of the Vindstyrka, it’s best to use it with the Ikea Home smart app. And if you don’t mind being Ikea-bound, then the Vindstyrka is a solid little monitor at a low price.

When I first used the Awair five years ago, it didn’t bother me that it had its own composite scoring system. The Awair sensor uses a fan and laser sensor to detect PM 2.5; toxic chemicals known as volatile organic compounds, or VOCs; CO_2; temperature; and humidity. Those individual scores go into Awair’s special algorithm that weights each of the five sensors and its actual toxic levels to humans over time, creating its color-coded scoring system. That means a score of 1 is a health hazard while a score of 100 means you’ve reached indoor air nirvana. The issue for me and my more air-aware self is when I see a reading of 100 on an indoor air monitor I think it means the air is bad. Yes, there is a tiny green light indicating overall good air, but still, it is confusing for me.

The score is the default setting on the display and can be easily overridden through the Awair app. By clicking on the gear in the upper right corner, you can change the display from the Awair Score to either temperature, humidity, CO₂, chemicals, dust PM 2.5, or a clock. Though, even when I change the display, the indicator light will shine for the Awair score, so right now my PM 2.5 is 4—that’s good—but my indicator light is a confusing orange because of the high humidity that puts Awair’s composite score at a moderate 55. And as for the VOCs or toxic chemicals, it measures for a mixture as it cannot tease out a specific VOC like formaldehyde or benzene.

I can’t help but think the QP Pro Air Quality Monitor was designed to sit on your desk and be used by those with excellent eyesight. I needed my reading glasses to use the touchscreen display. While the QP Pro’s app is easy to read, it’s odd that for a small monitor that does so much—it reads PM 2.5, VOCs, temperature, CO₂, and humidity—requires a wee bit of squinting. The QP Pro’s bright 3-inch Retina display lets you choose the sensor you want to prioritize to a bigger font. So, for example, you can tap the CO₂ and that will be the easiest-to-read number. Scroll on the screen and it will display the time, weather, outdoor AQI, and UV reading. And, in case of power outage, its lithium-ion battery has a four-hour life.

While this little monitor does a lot, I found it something I would use on a bedside table or next to my computer. The screen, while crisp and clear, is impossible to read from across the room. Still, for the price it packs a lot in a tiny package.

I liked the QP Lite Air Quality Monitor more than the QP Pro for the simple reason it had a clear display. And while it’s smaller than the Pro, its lithium-ion battery life is slightly longer at 6.5 hours. The OLED display and color indicator light, utilizing the AQI color codes, are easy on the eyes. And while the Lite doesn’t measure VOCs, it does measure PM 10, PM 2.5, CO₂, temperature, and humidity.

The Lite’s ring-box size makes it the perfect Airbnb or hotel room accessory. I recently brought it along with me to a New England wedding and my suitemate and I woke up to CO₂ above a thousand. We felt groggy and kept yawning. I opened the windows and we felt better in minutes. This is what an air quality monitor can do. Instead of a vague feeling that you’re getting tired or don’t feel great, one glance at the Lite’s screen and I knew to let the fresh air in. The touch bar at the top of the Lite took some getting used to, but tapping it scrolls through the readings.

By having a stand-alone air quality monitor, you will be able to see whether your air purifier is keeping up with the air in your physical space. In recent years, consumer indoor air quality monitors have improved in accuracy. After time those sensors can clog, giving off incorrect readings. I’ve used a hair dryer, set at the cool setting, to dislodge buildup in the sensors. Still, there seems to be a finite lifespan for the monitors I’ve used, as I’ve yet to have an air quality monitor work beyond four years. When placing or installing a monitor, look for the breathing zone height, around 3 to 6 feet off the floor.

I am still sometimes surprised when I see a poor air quality reading on the monitor. I won’t smell or see anything, but my monitor can sense that there is too much bad air. My building is currently having construction, and on several occasions I’ve seen the PM 2.5 reading go well beyond the safe level. At that point, I crank up the air purifiers. Since I started using both air quality monitors and air purifiers, my allergies—even in the spring—have been less severe. It’s made a difference in the quality of my sleep and my overall health. I no longer burn candles, cook without an exhaust fan, or spray air fresheners in my home, as I’ve seen how they negatively impact my indoor air in real time. Get one, and you might feel the same.

Even though many current air purifier models have built-in air quality sensors, having a designated air quality monitor provides independent assurance. After I became air-quality enlightened, I can anticipate ways to mitigate bad air. Using air quality monitors taught me to turn on my kitchen exhaust fan and crank up my air purifier before I turn on my gas stove. In the past, I didn’t think much of a little smoke from cooking. Now I do everything I can to avoid it.

Before you purchase your own indoor air-quality monitor, here are some things to know: Sensors on three of the air quality monitors reviewed, the AirVisual Pro, Awair Element, and PurpleAir, all performed well in an independent study. While low cost consumer air-quality monitors—let’s say, under $300—are far cheaper than those used by professionals, they are also less accurate and not easily calibrated. I have five air quality monitors in my home at the moment, and none are giving the exact same AQI, but they are close.

Consumer air-quality monitors use sensors to detect tiny invisible particles in the air and/or other contaminants. Some sensors use light scattering to detect fine particulate matter known as PM 10, like the dust you can see in a sunbeam, and the invisible health hazard, PM 2.5. PM 2.5 is the size that we’re most concerned about, that infiltrates the deepest parts of the lungs and enters the bloodstream.