Air Quality Testing: A Survey of the Leading Options

The saying “as easy as breathing” speaks to an interesting contradiction: though we are dependent on clean air for health and life, we take it for granted.

But we shouldn’t—not least of all because our air, much of the time, isn’t really very clean.

Air pollution is a leading cause of death, disease, and disability worldwide, and the issue is only getting worse. Fortunately, air quality testing—particularly monitoring through smart sensors connected to the IoT—provides leverageable data that can inform us how to combat air pollution.

In this post, I’ll further investigate this widespread problem, examine a case study wherein air quality testing helped combat air pollution, and survey some of the leading IoT options for air quality testing.

A Global Problem

smog obscuring the Shanghai skyline
Smog obscuring the Shanghai skyline

From haze over the San Francisco Bay to smog amongst the towers of Shanghai, air pollution is a truly global issue.

Worldwide, over 5.5 million people die every year as a result of unclean air, and air pollution cuts global life expectancy by an average of two years.

In the U.S.—and many other countries—the problem is only worsening. A recent report suggested that air quality in the U.S. has continually declined since 2016. And, according to the WHO, “over 90% of the worldwide population lives in places where air quality guidelines are not met.” 

A major part of the problem is a global lack of air quality testing data. Without data, it’s difficult to know what’s wrong, and, relatedly, whether current environmental initiatives are addressing the problem. Databases like the U.S.’s Air Quality Index (AQI) do exist, but such indices are far rarer in less developed countries, as can be seen on the real-time world air pollution index located here.

Complicating the issue is the fact that some governments which monitor air quality may not be forthright about findings. China’s government, for instance, has maintained the stance that “only it has the right to monitor [its] air pollution,” undermining the credibility of its data.

Additionally, monitoring practices may also be less than ideal; as reports, “In the UK’s ten largest cities during summer 2019, government monitors were not recording levels of particulate matter for 11,836 hours, potentially breaching EU laws on air pollution monitoring.” 

Another issue is a lack of hyper-local data. Knowing the overall air quality for a location (say, New York City) is helpful, particularly for measuring trends, but it’s not necessarily relevant to any individual’s situation. Someone who lives near a factory, or someone who lives in a building undergoing renovations, will be exposed to drastically different air than someone who lives on Roosevelt Island.

Thankfully, a new generation of smart sensors are allowing efficient, cost-effective, localized air quality testing—not only by governments, but by NGOs and concerned citizens, too.

Choking Hazards

city-dweller wearing a surgical mask
Many city-dwellers utilize surgical masks as a way to combat air pollution.

To know how to gather relevant data on air quality, it’s first necessary to know what makes quality air.

The EPA identifies six common pollutants which detract from air quality: Ozone (O3), Particulate matter (PM10 and PM2.5), Carbon Monoxide (CO), Nitrogen Dioxide (NO2), Sulfur Dioxide (SO2), Lead (Pb). Also of concern are CO2 levels and the levels of Volatile Organic Compounds (VOCs). VOCs are noxious vapors typically released from consumer products or from burning fuels. A useful EPA writeup on these factors can be read here.

An IoT sensor designed for air quality testing will ideally measure one or more of the above characteristics. And, because these characteristics are related to weather data, most sensors also monitor weather characteristics such as temperature, humidity, and barometric pressure.

Let’s look at what can happen when smart sensors measuring the above qualities are deployed, so as to provide actionable data.

Air Quality Testing Data In Action

Golden Gate Bridge in San Francisco with fog surrounding it

San Francisco, California, is a vibrant city: geographically striking, culturally significant, and architecturally beautiful.

It also has extremely poor air quality.

Long commute times, summer heatwaves (which inhibit ozone absorption), and rampant wildfires are largely to blame. In 2019, the American Lung Association declared the Bay Area one of the nation’s smoggiest regions. 

Unfortunately, air quality testing practices have been long been largely unsatisfactory. Testing costs are historically very high, meaning that measurements have tended to be limited in terms of both geographical area and measurement period.

But low cost, IoT-enabled sensors have been changing this. One such sensor is Awair, a San Francisco based company that manufactures wireless, indoor air quality monitors capable of tracking temperature, humidity, CO2, VOCs, and fine dust (PM2.5). In September 2017, a notable smog settled over the city, and Awair decided to utilize its database to see just how bad the problem was. The results were striking: “across the board, [homes] experienced at least a 50% increase in harmful [PM2.5] particles.” 

Awair air quality monitor
Awair’s air quality monitor

These unusually high readings were the result of wildfires raging in other areas of the state. The Awair team posited that high summer temperatures resulted in homeowners cracking a window in the hopes of cooling off. Unfortunately, this simple act allowed for particulate matter-ridden air to enter homes, potentially causing long-term health issues, in addition to immediate increases in asthma and allergy symptoms. In the future, San Francisco homeowners can utilize such sensor readings to determine whether or not to crack a window. 

While more can be read about this specific case study here, it’s important to note that it’s merely one of many demonstrating the highly useful insights IoT-based air quality testing can provide. Aeroqual, a manufacturer of air smart air quality monitors, lists numerous case studies demonstrating the breadth of use cases. Reviewing scientific literature, such as this EPA overview, is also worthwhile.

Diverse Sensor Options for Air Quality Testing

Given the ubiquity and impact of air pollution, governments, NGOs, and citizens may be interested in knowing about the market for air quality monitors.

It can be a confusing sector to investigate: there are numerous options available, and things can get a bit overwhelming. Further, it’s not always easy to know what to look for when considering a purchase.

To shed some light on the subject, I’ve conducted an investigation and identified several options worth considering. 

Evaluations were conducted based on six main factors: measurement capabilities, power source, data output, form factor, price, and operating environment. These factors are vital to consider; they determine how a sensor can be used, where it can be used, and what it can be used for. And, since indoor and outdoor air quality monitors have different requirements, I’ve grouped these options by whether they are designed for indoor or outdoor use.

UsageMeasurement CapabilitiesPower SourceData OutputForm FactorPrice
Awair GlowIndoor Temperature, Humidity, CO2, tVOCsPower OutletProprietary AppPlastic Enclosure$89
Atmotube PLUSIndoorTemperature, Humidity, Pressure, tVOCsRechargable BatteryProprietary AppMetallic enclosure and metallic carabiner$89
Ecowitt WH0290IndoorTemperature, Humidity, PM 2.5Rechargable Battery and Backup Solar PanelScreen DisplayPlastic Enclosure$70
uHoo AirIndoorTemperature, Humidity, Pressure,
CO2, tVOC, PM2.5, CO, O3, NO2
Power OutletProprietary AppPlastic Enclosure$329
Libellium Gases PRO v30OutdoorTemperature, Humidity, Pressure, CO, CO2, O2, O3, NO, NO2, SO2, NH3, CH4, H2, H2S, HCI, HCN, PH3, ETO, CI2, PM1, PM2.5, PM10Rechargeable Battery and Backup Solar PanelCloud Platforms, RS-485, CAN BusPlastic Enclosure~ $1000
Earthsense ZephyrOutdoorTemperature, Humidity, Pressure, NO2, NO, O3, CO, H2S, SO2, PM1, PM2.5, PM10Rechargeable Battery and Backup Solar PanelWifi, Bluetooth, GSMExtruded Aluminum BodyAvailable upon request
NCD Air MonitorOutdoorTemperature, Humidity, tVOC, CO2, Disposable BatteriesWifi (Temboo Kosmos Compatible)Plastic Enclosure$210
Decentlab DL-LP8POutdoorTemperature, Humidity, Pressure, CO2Disposable BatteriesLorawanPlastic EnclosureAvailable upon request
Aeroqual AQM65OutdoorTemperature, Humidity, Pressure, O3, NO2,
NOx, CO, SO2, PM10, PM2.5, PM1, VOC, H2S, CO2
Rechargeable Battery and Backup Solar PanelProprietary SoftwareMetal EnclosureAvailable upon request

It’s important to note that these are only a small selection of available sensors. As such, I’ve tried to present a wide variety of quality options (e.g. options geared more to professional monitoring, citizen science, etc.), so that one will hopefully align with your objectives. But this list is by no means exhaustive—there’s more to explore, and the world of IoT air quality monitors is rapidly expanding!

Breathe Easier with IoT

Air pollution is a widespread problem, with profound quality of life implications. But while the world has struggled with air pollution for years, a new generation of IoT enabled sensors are providing cost efficient, high-quality, and actionable data. This data can provide alerts about current air quality, evaluate the efficacy of implemented programs, and inform policy so that future programs are more effective.

Because many of these sensors are affordable, you can personally monitor air quality. By doing so, you’ll not only improve your own quality of life, but you’ll have the chance to contribute your data to databases like the World Air Quality Index project. This helps scientists and policy makers around the globe!

Kosmos on various devices

And, although implementing these sensors may sound difficult, Temboo’s Kosmos platform makes getting them up and running painless. Kosmos is a no-code platform that will walk you through set-up, help you visualize your environmental sensor data, and provide you with email / SMS alerts and machine-learning driven predictions. 

While particulate matter pollution is a significant concern, IoT-based air quality testing can help us breathe a little easier.