Editors' Note: This is the most recent version of the Amazon Smart Air Quality Monitor. Read our original review from January 13, 2022 below.

Running an air purifier can help ease your mind about dangerous gases and inhalable particles in your home. The tiny Amazon Smart Air Quality Monitor ($69.99) doesn't clean the air, but it measures particulate matter (PM 2.5), volatile organic compounds (VOCs), carbon monoxide (CO), humidity, and temperature around the clock, helping you understand what's in your indoor air and whether a purifier is necessary. It can send notifications to your phone, announce when it detects a high level of airborne pollutants via linked Echo devices, and offers comprehensive graphs of your indoor air quality over the last hour, day, and week. Ultimately, you'll still need a purifier to remove harmful particles and other contaminants from the air so they don't wind up in your lungs. But Amazon's Smart Air Quality monitor can help bring you peace of mind in knowing when you're breathing clean.

What Does the Amazon Smart Air Quality Monitor Detect?

The Amazon Smart Air Quality Monitor measures 1.8 by 2.6 by 2.6 inches (HWD). It features an air intake vent on the front and a multicolor LED indicator that displays your current indoor air quality (IAQ) at a glance. It also integrates with the Amazon Alexa app (available for Android and iOS) and Echo devices to help you keep tabs on your indoor air quality from your phone and with your voice.

As air flows through the intake vent, the device measures the temperature, humidity, particulate matter smaller than 2.5 microns in size (PM 2.5), carbon monoxide (CO), and volatile organic compound (VOC) levels.

PM 2.5 particles are microscopic (30 times smaller than the average human hair) and easy to inhale. Anything that causes smoke—such as burning candles, cooking, a fireplace, incense, or industrial emissions—can lead to elevated PM2.5 concentrations. This particulate matter can irritate your airways and cause breathing problems; it's particularly worrisome for 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 measure the concentration of both PM2.5 and PM10 matter (particulate matter up to 10 microns, including dust, mold, and pollen), but the Amazon Smart Air Quality Monitor only detects and reports on the former.

CO is an odorless and flammable gas that can be toxic at high concentrations. Fuel-burning appliances such as cars, clothes dryers, fireplaces, furnaces, generators, grills, ovens, power tools, stoves, and water heaters all produce this. While the Smart Air Quality Monitor is capable of monitoring CO levels, Amazon says it shouldn't be used as a replacement for a CO alarm. The monitor doesn't measure carbon dioxide (CO2) or radon either, two other potentially life-threatening invisible gases.

It does measure VOCs, which are potentially harmful gases from things like cleaning products and paint. The US Environmental Protection Agency (EPA) says 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. VOC concentrations are typically much higher indoors than outdoors.

The Amazon Smart Air Quality Monitor takes all of these factors into account and calculates your IAQ (indoor air quality) score. It considers an IAQ score between 100 and 65 as "Good" and represents it with a green light. The monitor defines scores between 64 and 35 as "Moderate" and shows this in yellow. It categorizes scores of less than 35 as "Poor" and displays it in red.

Setting Up and Using the Amazon Smart Air Quality Monitor

The monitor comes with a power cord and adapter. To set it up, place the device in an area with good airflow and avoid blocking the air intake vent. Next, plug it in using the power adapter; the LED should blink blue to indicate that it's in setup mode.

After that, open the Amazon Alexa app on your phone or download it and log in with your Amazon credentials. Once I opened the Alexa app, a pop-up informed me that the Smart Air Quality Monitor was ready to be set up. Next, the app asks you to locate and scan the QR code for your device, which you can find in two places: the quick start guide included in the box and on the bottom of the monitor.

Scan the QR code, wait for the device to connect, and then optionally assign it to a room group in the app. After a seven-minute initial calibration, it should calculate your IAQ score. The monitor will then continue to calibrate for two more days as it adjusts to the environment.

After setting up the monitor, you can view your IAQ dashboard in the Alexa app. The dashboard shows your current IAQ score, followed by the latest temperature; the humidity percentage; and PM2.5, CO, and VOC readings. Below that are graphs of your average hourly, daily, and weekly IAQ scores. To view trend graphs of individual metrics, select one of the tabs at the top of the dashboard.

The app makes it easy to view your air quality trends and the factors that contribute to your IAQ score. It also does a good job of explaining each metric and its health effects, and offers tips to help you improve your air quality. For example, the app states, "Try reducing indoor PM levels by using an air purifier or cleaning vents and fans and replacing filters in home ventilation units on a regular basis." It also recommends that you "properly service and ventilate fuel-burning appliances."

Most smart air purifiers, such as the $549.99 Dyson Purifier Cool TP07, boast similar monitoring features. In its companion app, the TP07 offers graphs of your overall air quality, PM2.5, PM10, VOC, NO2 (nitrogen dioxide and oxidizing gases, such as gas stoves and car exhausts), temperature, and humidity levels. It also offers educational information to help you understand the pollutants affecting your air quality.

Amazon's Smart Air Quality Monitor doesn't feature a built-in speaker to sound an alarm if it detects elevated airborne pollutant levels. When your air quality drops to a poor state, however, it can send a notification to your phone and announce an alert via linked Echo smart speakers and smart displays. After pairing it with an Echo device, you can also ask Alexa about your indoor air quality.

In testing, I found that Alexa can be a bit finicky about how you phrase questions. In response to the question, "Alexa, what's the indoor air quality," my Echo Show told me the current IAQ score and showed graphs of the latest temperature, humidity, PM, CO, and VOC readings. But when I phrased the question slightly differently—"Alexa, how's my indoor air quality?"—the virtual assistant said, "That's not supported yet."

How the Amazon Smart Air Quality Monitor Performs: The Palo Santo Test

I set up the Smart Air Quality Monitor in the same room as a Dyson TP07 and the devices offered similar readings for overall air quality, temperature, and humidity. To further evaluate their performance, I lit a stick of palo santo wood within equal distance of both devices, then timed how long it took each one to measure a high level of particulate matter and to rate the overall air quality as poor. For context, the TP07 has a few more levels on its rating scale: good (green), fair (yellow), poor (orange), very poor (red), extremely poor (maroon), and severe (purple).

Smoking out the room with a stick of palo santo to test the Amazon Smart Air Quality Monitor (on the TV stand) against the Dyson TP07 (to the left of the TV)

Before lighting the palo santo, both devices rated the overall air quality as good. The Smart Air Quality Monitor measured the room temperature at 79 degrees Fahrenheit, the humidity level at 55%, PM2.5 levels at 6 micrograms per cubic meter, CO levels at 2 ppm, and VOC levels at 1. The Dyson TP07 reported similar starting measurements, including a 74-degree room temperature, a 54% humidity level, a PM2.5 level of 8 micrograms per cubic meter, and NO2 and VOC levels both at zero.

After I lit the palo santo and wafted the smoke around both devices, the reported PM measurements steadily began to climb. The TP07's air quality indicator light changed to yellow after 3 minutes and 22 seconds, and then turned maroon after about four-and-a-half minutes. After around 10 minutes, it became purple.

About five minutes in, the Amazon Smart Air Quality Monitor reported a moderate level of PM, but still rated the overall IAQ as good. At the seven-minute mark, its LED switched to yellow to indicate a moderate IAQ level. At around 10 minutes, it reported a high level of PM but maintained a moderate IAQ rating. Around 12 minutes into the test, the Smart Air Quality Monitor's LED changed to red.

Air quality readings from the Amazon Smart Air Quality Monitor (left) and Dyson TP07 (right) on the day of my palo santo test

As soon as the Smart Air Quality Monitor's LED shined red, Alexa audibly warned, "The indoor air quality in your home recently changed to poor," on both of my Echo devices. At the same time, the monitor also sent a notification to my phone.

Amazon doesn't specify how large of a space the Smart Air Quality Monitor can handle, but recommends setting up one in each room. For my small open-concept kitchen, dining, and living room, I only seem to need one unit. While cooking in the kitchen one day, the Smart Air Quality Monitor in my living room detected smoke and Alexa alerted me that the air quality dropped to poor. Obviously, putting a monitor in every room of your home could get costly; I'd rather spend my money on a high-quality smart air purifier that can handle a large area (like the $449 Coway Airmega 250S) than several monitoring devices.

What's In Your Indoor Air?

No matter where you live, the air inside your home is probably more polluted than the air outside, according to the EPA. The relatively affordable Amazon Smart Air Quality Monitor can help you keep a closer eye on your indoor air quality. It competently monitors the temperature, humidity level, concentration of particulate matter, carbon monoxide (CO), volatile organic compounds, and overall air quality of the room it's placed in—but keep in mind it doesn't actually clean the air. I'd be willing to bet that Amazon integrates this technology into a full-blown smart air purifier in the future, but until then, the Smart Air Quality Monitor can pair well with a traditional purifier to help you better understand the air you breathe.