>>> Join Us in the Fight Against Air Pollution

Measuring Your Air Quality Is Important. Here’s Why.

We spend 80% of our time indoors, where air can be polluted by off-gassing furniture, cooking, and cleaning chemicals. Insufficient ventilation can lead to high CO2 levels, causing headaches, fatigue, and reduced cognitive performance. Measuring indoor air quality helps identify these pollutants, allowing you to create a healthier and more comfortable living environment.

Equally important is measuring outdoor air quality. Outdoor pollutants like PM2.5, PM10, and nitrogen dioxide can cause respiratory and cardiovascular issues. These pollutants can enter your home through windows and doors, affecting indoor air quality. By monitoring outdoor air, you can take precautions such as limiting outdoor activities on high-pollution days and improving indoor ventilation.

Understanding indoor and outdoor air quality provides a comprehensive view of the air you breathe. This knowledge allows you to proactively manage your environment, ensuring a safer and healthier space for you and your family. This is especially helpful with Homey, as you can create automation based on differences between indoor and outdoor pollutant levels.

Homey Certified Air Quality Monitors

Both AirGradient monitors have an officially supported Homey integration, meaning you can expect a high-quality integration with regular support and updates.

AirGradient PRO Kit

AirGradient ONE

Indoor Monitor

The AirGradient ONE is an indoor air quality monitor with native Homey support.

This monitor measures PM1, PM2.5, PM10, CO2, TVOCs, NOX, temperature and humidity and has a built-in color LED bar and small display.

The AirGradient ONE sends data to your Homey Pro over WiFi, and it’s perfectly suited for monitoring the air quality in kitchens, bedrooms, and living areas inside your home. The Homey platform also allows for easy integration of multiple monitors and automation for monitors and devices in different rooms, allowing you to create a truly smart home.

Our indoor air quality monitor’s enclosure allows it to be mounted on a wall easily or to sit on a desk. Cable routing on the back of the device allows you to manage and hide cables, ensuring the monitor blends in wherever in your house it is placed.

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AirGradient PRO Fully Assembled

AirGradient Open Air

Outdoor Monitor

The AirGradient Open Air is a Homey-certified outdoor air quality monitor.

It also measures PM1, PM2.5, PM10, CO2, TVOCs, NOX, temperature, and humidity, allowing you to quickly and easily assess the quality of outdoor air.

Ideally paired with an AirGradient ONE and Homey Pro, these two devices will allow you to identify indoor and outdoor air quality trends and monitor trends between outdoor and indoor air quality. This will give you a full picture of your air quality and can lead to actionable suggestions, such as knowing when to open the windows or when to ‘lockdown’ your home.

The Open Air is fully weather-sealed, meaning it can be mounted on the side of your home or nearby. With a WiFi connection, it can send regular updates to your Homey dashboard and give you further information on your local air quality.

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Hassle-Free Setup

Homey Supported logo


The AirGradient Homey integration makes the setup process seamless. All you need to do is connect your AirGradient monitor to the same network as your Homey Pro, install the AirGradient app from the Homey App Store, and the monitor will automatically be discovered. Then, add the monitor, and you’re ready to integrate!

You Own Everything

We’ve noticed a worrying trend in the air quality monitoring industry. Many manufacturers are restricting access to data - even to monitors you own - to monetise it. We couldn’t be more against this approach.

Open Data

You own all of the data from your AirGradient monitors and can use it however you want. We welcome you to submit the data to Open AQ or the AirGradient map, but the data is yours, and you can use it however you see fit.

Cloudless Usage

AirGradient and Homey Pro can run entirely locally, meaning you don’t need to worry about your data. The monitor will retain full functionality, even if it isn’t connected - you can even manually update the monitor without ever connecting it to the internet.

Transparent and Understandable Ts & Cs

While many companies try to deceive users by creating lengthy and hard-to-understand terms and conditions, we put ours at the center of our mission. In fact, we encourage you to read our terms and conditions. Long story short: Your monitor and data are yours.

No Lock-in

Regardless of what happens to AirGradient, your device is always usable due to its open-source nature. Connecting your monitor to Homey or another platform will ensure it continues operating and never becomes a brick

Active Community Support

Whether you want an out-of-the-box Homey-certified air quality monitor or you want to fully use the open-source license and tailor your monitors to exactly your needs, we have a strong and active community that grows daily, where everyone is included and part of a larger movement.

The AirGradient forum facilitates conversations among community members, which has led to bug fixes, device improvements, and even community members creating their own solutions. Our Homey certification requires that we have ongoing support, and much of this is driven by our fantastic community.

Following our open-source beliefs, we welcome all participation on the forum - even in the case of reporting issues with the devices. We appreciate every member who takes the time to share their experiences with AirGradient, and it’s this information that allows us to continue improving our products.

Become a Citizen Scientist

If you use the AirGradient data platform with an AirGradient Open Air, you can opt-in to share your outdoor data with the public and OpenAQ. OpenAQ is a non-profit organisation collecting and organising worldwide air quality data and making it available for the public and research. Your data is then also available on the AirGradient map together with thousands of other monitors from OpenAQ.

This data is freely available for anyone and can go towards improving public health initiatives and even shape policy making. The more accessible air quality data, the better! With the included carbon dioxide sensor, you can also help identify local emissions sources that lead to climate change.

DIY or Pre-built. The Choice Is Yours


Our air quality monitors come in a DIY kit or prebuilt configuration. The DIY kit allows you to save money by assembling the monitor yourself - it’s also a great way to learn about the inner workings of your open-source monitor.

The DIY kits are easy to build (no soldering required), and everything required is inside the box. With the manual, you can assemble your DIY monitor and integrate it with your Homey Pro in under 15 minutes. You can contact us directly or ask on our forum if you run into issues.

We also offer both monitors in a pre-built configuration that comes ready to integrate with Homey out of the box. This monitor also comes with a one-year warranty, multiple certifications, and a lab test report, which we provide to ensure the components and monitor are working very accurately.

Built to Last

At AirGradient, we emphasize science, ensuring we use only high-quality components that are performant and accurate. However, some components have finite lifespans, meaning they need to be replaced eventually. To overcome this, we’ve built our monitors with repairability and long-term use in mind.

All components in AirGradient monitors can be purchased individually, meaning that if a component fails, there is no need to replace the whole monitor - just the faulty part. In the case of non-AirGradient parts, these replacement parts can be purchased either from us or from a local distributor.

This combination of open-source hardware and software ensures that your AirGradient monitor will provide air quality insights for many years to come.

High-Quality Components

AirGradient Open Air features
AirGradient One features


Both homey-enabled monitors use high-quality sensors from industry leaders like SenseAir, Sensirion, and Plantower, ensuring accuracy through rigorous testing and calibration.

The SenseAir S8 CO2 sensor utilizes NDIR technology with automatic baseline calibration (ABC) every seven days (customizable), providing very accurate measurements. High levels of CO2 can indicate poor ventilation, causing headaches, tiredness, and reduced cognitive performance. Increasing outdoor CO2 levels can be indicators of climate change.

For PM2.5 measurements, AirGradient employs the Plantower PMS5003(T) sensors, which use laser scattering technology and have been extensively tested in various studies. Elevated PM2.5 levels are linked to numerous health issues, including premature mortality, heart or lung problems, and asthma attacks. The sensor module is factory-calibrated.

TVOCs and NOX are measured with the Sensirion SGP41 sensor, which detects volatile organic compounds from indoor sources like off-gassing furniture, aggressive cleaning liquids, and harmful gases from gas stoves or boilers. Outdoors they can be emitted by vehicles and indicate areas of high pollution. The measurements are based on the Sensirion VOC Index, which represents changes in VOC concentrations. Temperature and humidity are measured with the Sensirion SHT3x/4x sensors, known for their accuracy and for providing insights into indoor comfort levels and mold risk.

We work very closely with several leading universities on air quality monitoring, and due to its performance and affordability, our indoor air quality monitor has been selected for the largest study of classroom air quality in the world. We also work on many co-location projects with our outdoor air quality monitor and leading universities worldwide. You can read more about our work with research institutions on our research page.

Easy to Extend

AirGradient Open Air features
AirGradient One features


Both monitor’s open-hardware / open-source nature allows easy changes and additions to the firmware and hardware. The board is powered by an ESP32-C3-MINI microcontroller that is easy to program with a wide ecosystem and has integrated WiFi and Bluetooth capabilities.

The ESP32 can be directly flashed through the USB C port, making changes in the open-source firmware easy.

For those who would like to adjust the monitor, breakout pins are available for I2C and three additional IOs. In addition, you can repurpose the two UARTs. The board provides both 5 and 3.3 volts.

We integrated an external hardware watchdog chip that automatically reboots the unit in case something goes wrong, enabling the monitor to achieve high uptimes.

AirGradient ONE Monitor

AirGradient ONE Technical Data

Below is the technical data of the newest version of the AirGradient ONE. Available in our online store.

SpecificationDescription
ModelI-9PSL (AirGradient ONE, 9th Generation)
MicrocontrollerESP32-C3-MINI (32-bit RISC-V single-core processor, up to 160MHz, 384 KB ROM, 400 KB SRAM, 8 KB SRAM in RTC, 4 MB flash in chip package)
WiFi2.4GHz IEEE 802.11 b/g/n-compliant
DisplayOLED display 1.3 inch (I2C 128x64px)
BluetoothBluetooth LE: Bluetooth 5, Bluetooth mesh
ExtensionsBroken out on PCB: I2C, 3 GPIO, 2 UART
Peripherals11 RGB-LEDs, Push Button, Reset Button, USB C Connector
External Hardware WatchdogTexas Instruments TPL5010
CO2 Sensor ModuleSenseAir S8 (NDIR). 0 to 10000ppm. Accuracy: ±40 ppm ±3% of reading at 5 to 30°C, 0-85% RH (400 - 2000ppm range)
Particle Sensor ModulePlantower PMS5003 (laser scattering principle). Accuracy: ±10%@100~500μ g/m³, ±10μg/m³@0~100μ g/m³
Temperature and Humidity ModuleSensirion SHT40. Accuracy: Temperature ±0.2°C @ -40 to + 125°C; Humidity ±2% RH @ 0 - 100% RH
TVOC/NOX ModuleSensirion SGP41. Accuracy: TVOC <±15 @ 0 to 500 VOC Index; NOX <±50 @ 0 - 500 NOX Index
EnclosureASA Plastic, UV Resistant and Weather Proof
Cable2m USB C Cable including Data Lines for Flashing
Power Plug (not included)

2A 5V USB A Power Plug is Required

Dimensions & Weight130 x 130 x 35mm, 350 grams
CertificationsCE, RoHS, REACH, RESET Air, FCC ID: 2AC7Z-ESPC3MINI
AirGradient Open Air Monitor

AirGradient Open Air Technical Data

Below is the technical data of the default version of the Open Air as it is available in our online store.

SpecificationDescription
ModelO-1PST (AirGradient Open Air)
MicrocontrollerESP32-C3-MINI (32-bit RISC-V single-core processor, up to 160MHz, 384 KB ROM, 400 KB SRAM, 8 KB SRAM in RTC, 4 MB flash in chip package)
WiFi2.4GHz IEEE 802.11 b/g/n-compliant
BluetoothBluetooth LE: Bluetooth 5, Bluetooth mesh
ExtensionsBroken out on PCB: I2C, 3 GPIO, 2 UART
PeripheralsStatus LED, Push Button, USB C Connector
External Hardware WatchdogTexas Instruments TPL5010
Particle Sensor ModulePlantower PMS5003T (laser scattering principle). Accuracy: ±10%@100~500μ g/m³, ±10μg/m³@0~100μ g/m³
Temperature and HumidityENS210 (inside PMS5003T module). Accuracy: Temperature ±0.2°C @ 0 - 70°C; Humidity ±3.5% RH @ 20 - 80% RH
CO2 Sensor ModuleSenseAir S8 (NDIR). 0 to 10000ppm. Accuracy: ±40 ppm ±3% of reading at 5 to 30°C, 0-85% RH (400 - 2000ppm range)
TVOC/NOX ModuleSensirion SGP41. Accuracy: TVOC <±15 @ 0 to 500 VOC Index; NOX <±50 @ 0 - 500 NOX Index
EnclosureASA Plastic, UV Resistant and Weather Proof
Mounting OptionsWall or pole mounting options
Cable4m USB C Cable including Data Lines for Flashing
Power Plug (not included)

2A 5V USB A Power Plug is Required

CertificationsCE, RoHS, REACH, FCC ID: 2AC7Z-ESPC3MINI

Activities and Stories From and About our Community

We are blessed to have such an active community. Read more about community engagement.

More articles on our blog.

Reviews

We are very thankful for the overwhelming support we get for the AirGradient air quality monitors and are especially thankful for people that write about their experiences using the monitors. Below is a wide range of reviews from AirGradient users!

The AirGradient Manifesto

This manifesto reflects our core values and the principles we stand for:

Positive Disruptor

We must be bold. We always follow our convictions and call out the issues that matter, sharing our views on topics surrounding air quality and environmental responsibility. We will not compromise for profit. We believe that open, informed, and candid discussions are the catalysts for meaningful change. We will lead by example and become a driving force for environmental monitoring.

Responsible Products

We will deliver benefits for both people and the planet. This is why we prioritise creating high-quality air quality monitors with designs that enable easy repairs and recycling, thereby extending the product’s lifespan and reducing its environmental footprint.

Open Science and Research

Our research is driven by a commitment to environmental protection, not by profits. This is why we don’t patent our air quality monitor designs but on the contrary, share them openly, allowing everyone to build them and to contribute to positive change. We do not lock users into proprietary eco-systems and we encourage sharing of air quality data and algorithms as a public good.

Community Building

We want to raise awareness about air pollution through active community building with a strong focus on informing about the dangers of air pollution. We actively support environmental justice organisations and educational institutions in their missions to provide healthier environments for everyone.

Profit Follows Impact

To deliver positive impacts on the communities, and the environment, we must sustain our business model. However we will not prioritise profits above our convictions. We embed this rationale into our everyday decision-making processes throughout all layers of our company. (e.g. by joining 1% for the Planet).

Transparency and Accessibility

AirGradient is built on a foundation of openness and inclusivity. We aim to make our products and services available to a wide range of users with a special focus on underrepresented communities. We strive to work with all organisations that want to make a positive contribution independent of their financial means.

Keep in Touch

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