Our 11 Favorite Air Quality Monitors We’ve Tried (2025)

I wish I had used the IQAir AirVisual Outdoor Monitor years ago when I first tested IQAir’s AirVisual Pro Indoor Air Quality Monitor (above). The display gives real-time indoor monitoring along with data from the closest outdoor air quality station, or your very own right-outside-the-window IQAirVisual Outdoor. There’s so much more accuracy in having both a dedicated indoor and outdoor monitor. Having both of IQAir’s monitors enables the AirVisual Pro to show both side-by-side readings of indoor and outdoor on its easy-to-read screen.

Depending on the index number, the visual of the screen’s two boys will be green with a smile for good air and seem disillusioned at moderate yellow air, going all the way to purple with a respirator mask for bad air. Sometimes both boys are smiling green, sometimes the indoor boy is happy and the outside one is mired in dirty air. There’s real agency in knowing both the indoor and outdoor air quality index. The monitor also pairs with IQAir’s intuitive app, which has one of the best user experiences I’ve tried.

Unlike PurpleAir’s plug-and-play crowdsourced air quality map, IQAir has a registration process for accepting data from your Outdoor monitor. Submission requirements include photos of your mounted outdoor monitor. IQAir’s Outdoor comes with a mounting plate, two UV-resistant cable ties for a pole mount, and wall plugs and screws for a wall mount. I’m unable to drill into the brick outside my building, and IQAir doesn’t have an option for placing it on a windowsill. There’s no stand to keep it upright. The power adaptor cannot get wet with rain or snow, and it’s suggested to place it at a minimum of 5 feet off the ground. IQAir requires a photo of your Outdoor placement. I took a picture of the Outdoor monitor on my windowsill and submitted it to IQAir.

My submission to be a contributor for the app was rejected. An email from IQAir detailed why: “The data reported from your monitor doesn’t correlate with surrounding stations. Please make sure the environment is well ventilated and check if there is any pollution source nearby, then resubmit your publication so that we could review it again. From the provided photos, it appears that your installation does not ensure good airflow … Make sure air inlet is completely unobstructed, and air can freely flow around the device.”

IQAir included a photo of a monitor secured above the door on a freestanding house. And while I’ve yet to resubmit, having an outdoor monitor that works with my IQAir Air Visual has been helpful. When my neighbors use their fire pit, both my PurpleAir Zen and my IQAir Outdoor registered a PM 2.5 of 160, letting me know to shut my kitchen window. And it has four sensors that can pick up PM 2.5, CO₂, temperature, humidity, and barometric pressure. I have to either look at my AirVisual monitor for a real-time reading or open the app, because the IQAir Outdoor doesn’t have an indicator light; it’s truly meant to be tucked away outside.