AirGradient Open Air

Outdoor Air Quality Monitor

Open Air is an outdoor air quality monitor enabling you to know if the air quality is healthy or not. It measures PM1, PM2.5, PM10, Temperature and Humidity. It’s fully open-source and customizable, so you can extend it in whatever way you like.

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Why Air Quality is So Important

According to the World Health Organization, more than 90% of the people breathe unhealthy air. Air pollution is the biggest driver of premature death of all environmental health risks. With climate change and the warming of the planet, air pollution, e.g. through wildfires are also increasingly becoming a major issue in regions with previously very clean air.

Air quality can quickly fluctuate between good and unhealthy levels and thus a dense network of air quality monitors ensures that people know when they need to protect their health. The Open Air outdoor monitor keeps you always informed about the air you breathe.

Key Characteristics

The monitor measures PM1, PM2.5, PM10, Temperature and Humidity. In future we will offer options with TVOC and CO2 sensors. The standard version uses two independent particle sensors with integrated temperature and humidity sensors.

This monitor focuses on measuring particulate matter, especially PM2.5. PM2.5 has the potential to cause significant harm to our well-being. These tiny particles are released into the air through various sources such as vehicle emissions, industrial activities, burning of fossil fuels or wildfires. When inhaled, PM2.5 particles can penetrate deep into our respiratory system, leading to a range of health issues. Long-term exposure to PM2.5 has been linked to respiratory and cardiovascular diseases, including asthma, bronchitis, heart attacks, and even premature death.

The Open Air constantly measures the air quality and informs you when the air becomes unhealthy, and you should take protective measures.

We work very closely with a number of leading universities on air quality monitoring and our monitor has been selected for the largest study of classroom air quality in the world due to its performance and affordability. You can read more about our work with research institutions on our research page.

Flexible Data Platforms

The AirGradient Open Air monitor is unique as it gives you full flexibility on how you want to monitor and use the data. Being open-source you are not locked in to any specific data platform but can connect the data to any server, i.e. Home Assistant or use the AirGradient data platform - a data platform specifically made for air quality monitoring.

This gives you complete ownership and freedom of your data and our community has built a number of extensions to existing data platforms, e.g. home assistant with ESPHome.

Of course you can also use the AirGradient dashboard that is already pre-flashed on the monitor and very easy to setup.

This powerful dashboard lets you immediately see the air quality and environmental status of multiple locations. Built for speed and scale. You can set up specific alerts and are notified automatically if air quality is exceeds your defined ranges.

Get powerful daily and weekly reports detailing the air quality of each location, providing you with a clear, concise summaries at a glance.

Outdoor monitors can also be displayed on the AirGradient Map and you can opt-in to share your outdoor data with openAQ, a non-profit with the mission to deomocritize air quality data and make it freely available.

AirGradient Map with OpenAQ Data

If you use the AirGradient data platform, you can opt-in to share your outdoor data with the public and openAQ. OpenAQ is a non-profit organisation collecting and organizing 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.

Easy to Assemble, Setup & Install

The kit is very easy to assemble, and you can also get the monitor as fully assembled version. We provide detailed instructions and videos on how to connect the monitor to your WiFi network and set it up on the dashboard and map. If you run into any problem, just contact us directly and we are happy to help. You can also ask questions in the AirGradient Forum and get valuable tips from the community.

Mounting Options

The monitor can be mounted on walls or poles. For pole mounting, use two stainless steel zip ties and feed them through the zip tie holders. Alternatively you can use two screws and mount the monitor on a wall. To prevent theft, there is a small hole on the monitor that you can use with a secure screw to prevent the monitor from easily taken off.

The enclosure is fully weather proof so it can be mounted being exposed to the elements.

Optimized Enclosure

The enclosure has been designed with two primary goals, firstly to ensure accurate measurements of the air quality and secondly to be robust and long lasting.

For accurate measurements it is important that there is a good airflow to the sensor modules, that air loops in front of the sensor modules are avoided and that the risk of condensation inside the enclosure is as much as possible reduced.

The enclosure itself is very robust and consists of high quality ASA plastic that gives an excellent durability as well as UV protection.

Available as Kit or Fully Assembled

You can either buy the components yourself and build it on your own, or purchase as a kits or fully assembled unit with warranty and test report from our online shop.

Open Air Kit

Outdoor air quality monitor with dual PM modules. Measures PM1, PM2.5, PM10, Temperature and Humidity. Comes with pre-assembled PCB and can be built without soldering within minutes.

  • Model O-1PP Kit
  • Dual PM sensors
  • 4m USB C cable (w/o power plug)
  • Easy to assemble kit
  • 24 months AirGradient data platform with map (or connect it to your own server, e.g. home assistant)
  • Fully open-source code so you can easily make adjustments

USD 95.00

Build Instructions Get It From Us

Open Air Fully Assembled

Outdoor air quality monitor with dual PM modules. Measures PM1, PM2.5, PM10, Temperature and Humidity. Fully assembled and tested ready to be used immediately.

  • Model O-1PP (Fully Assembled)
  • Dual PM sensors
  • 4m USB C cable (w/o power plug)
  • Fully assembled
  • 24 months AirGradient data platform with map (or connect it to your own server, e.g. home assistant)
  • Fully open-source code so you can easily make adjustments
  • Tested in our test chamber with test report
  • Certified: CE, FCC, RoHS, REACH
  • 12 months warranty

USD 155.00

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Technical Data

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

O-1PP (AirGradient Open Air)
ESP32-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)
2.4GHz IEEE 802.11 b/g/n-compliant
Bluetooth LE: Bluetooth 5, Bluetooth mesh
Broken out on PCB: I2C, 3 GPIO, 2 UART
Status LED, Push Button, USB C Connector
External Hardware Watchdog
Texas Instruments TPL5010
Particle Sensor Module
2x Plantower PMS5003T (laser scattering principle). Accuracy: ±10%@100~500μ g/m³, ±10μg/m³@0~100μ g/m³
Temperature and Humidity
ENS210 (inside PMS5003T module). Accuracy: Temperature ±0.2°C @ 0 - 70°C; Humidity ±3.5% RH @ 20 - 80% RH
ASA Plastic, UV Resistant and Weather Proof
Mounting Options
Wall or pole mounting options
4m USB C Cable including data lines for flashing

Keep in touch

Subscribe to our newsletter, and we keep you informed about new features of our open hardware monitors, innovative use cases of air quality monitoring and our mission to democratize air quality data.

Ideally combined with indoor monitors

In order to fully understand the air quality of your environment, we recommend you also monitor the air quality indoors. We spend most of our time indoors and often the indoor air can also be very unhealthy due to indoor pollutants like volatile organic components (VOCs), or high particle concentrations from cooking. High CO2 values due to insufficient ventilation can lead to tiredness and lower cognitive performance.

By monitoring both, indoor and outdoor air quality you get valuable additional data, e.g. where the pollution is coming from, how well does the ventilation and air purification of your home works etc. The AirGradient dashboard is especially suited to compare indoor and outdoor air quality in combined reports and charts.

Go to our indoor air quality monitor page to learn more about our open-source indoor monitors.

In 2019, 99% of the world population was living in places where the WHO air quality guidelines levels were not met. Ambient (outdoor air pollution) in both cities and rural areas was estimated to cause 4.2 million premature deaths worldwide in 2016.

World Health Organisation

Easy to Extend

The open-hardware / open-source nature of the monitor allow easy changes and additions on the firmware as well hardware. The board is powered by an ESP32-C3-MINI microcontroller that is easy to program with a wide eco-system and has integrated WiFi and Bluetooth capabilities.

The ESP32 can directly be flashed through the USB C port and thus changes in the open-source firmware can easily be done.

For the ones, who would like to make adjustments to the monitor, there are breakout pins 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 and thus the monitor can achieve high up times.


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!


BBC Newsround featured our indoor monitor that is used in the SAMHE project, the largest study on classroom air in the world. A big part of this project is to increase the awareness of healthy air among primary and secondary students.

Jeff Geerling on Basic Kit

We are a huge fan of Jeff Geerling YouTube Videos, and he made a fantastic video review when we had only our first air quality kit, the Basic kit. It’s great that he also talks what actually made him want to know more about the air quality in his basement office.

Igor Bubelov on DIY Pro and Outdoor Monitor

Igor purchased and reviewed our indoor DIY kit and we liked his unbiased review on our indoor monitor so much that we gave him two outdoor monitors with the hope that he would also write about them. And it actually happened! Read his detailed review on the Open Air.

Nicholas Schmidt on DIY Pro and Outdoor Monitor

Many thanks also to Nicholas who reviewed our indoor and outdoor open hardware kits and wrote about his reasons to know about the air he breathes. By the way, in the meantime we made some changes on the outdoor enclosure and the assembly with the cable management is much easier now.

See The Air Blog on Basic Kit and Display

Sotirios not only wrote about our basic kit but also about our open sourced small information display that is particularly popular with student projects in schools.

Yosua Ian Sebastian on AirGradient Indoor Kit with Home Assistant via ESPHome

This is a great technical review how Yosua setup our open hardware indoor monitor with his own server based on home assistant.

Where is Your Review?

If you like our open hardware monitors please spread the news and consider writing a review about them! Since our monitor designs are open and under Creative Common license, and we want honest and unbiased reviews it is against our ethos to pay for reviews. But we would be very happy to support in other ways. Get in touch with us.

Open Hardware, Open Source, Open Data

As the name implies, the Open Air has been designed from the ground up with the strong desire democratizing air quality monitoring. Access to the information about the air you breathe should not be a privilege of the rich. Air pollution is one of the largest global environmental and health risks, requiring a high density sensor network to understand and solve the problem. We provide a blueprint of a robust, affordable and open design that citizens and NGOs worldwide can use to accurately measure air quality.

Fully Open Source

All code, schematics, 3D files etc. are open-source and published under CC-BY-SA 4.0 license. You can easily adapt the hardware as well as flash your own firmware.

You own your Data

There is a trend in our industry to monetize air quality data to the extent that often the owner of the monitor does not own the data. We believe this is wrong. The data that your monitor generates should belong to the owner of the monitor.


We have partnered up with openAQ, a non-profit with the mission to provide air quality data to influence policy, and to enable the public to access information on air pollution through open data and open-source tools.

1% for the Planet

We joined 1% For The Planet and pledged to donate at least one percent of your annual sales to non-profit organisations dedicated to protect the planet. You can read more about our motivation to join 1% for the planet on our plog post ‘Why We Joined 1% For The Planet’


We are fortunate to have such a strong community sharing our mission to bring open, accurate and affordable air quality monitoring to everyone running thousands of open-hardware monitors in more than 70 countries around the world.

Statements from People Involved

Having used the AirGradient indoor DIY kits as well as the commercial AirGradient ONE in awareness projects with schools and universities here in Thailand, I am very keen on piloting this new outdoor monitor. I am also interested in exchanging ideas and resources for student engagement with this open source projct.

The San Joaquin Valley of California has extreme climate injustice and the worst air quality in the United States, yet continues poorly monitored. The SEEN Team has partnered with AirGradient to facilitate low-cost monitoring in rural disadvantaged communities, and to increase awareness and education related to air quality. We intend to provide more and better real-time air quality information for local decision makers to act in the best interest of their underserved communities.

Angel S. Fernandez-Bou, PhD, Central California

I’m very happy to contribute to this open hardware project with my product design experience and working with the team to not only ensuring a beautiful look but a highly functional design. Turning the required air flow characteristics and vent specification into a good looking product was a challenge I really liked. I’m looking forward to see the product in many Citizen Science projects around the world.

Having tested numerous air quality sensors for the projects we are doing I found myself extremely impressed with AirGradient. Not only are they technically first class with their product, they have a level of engagement and adaptability which makes working with them very easy. A welcome element to this is their clear commitment to the importance of environmental issues, showing itself in their interest in the details of our projects - all this helps them to deliver…!

Professor Rod Jones
University of Cambridge

AirGradient have consistently gone above and beyond their contractual duties in order to better support the SAMHE Project. They have shown great flexibility and a genuine interest to listen to the complex needs of the project; as a result, they deliver valuable products and a friendly service, both in a manner that is timely for the project.

Henry Burridge
Imperial College London

Why we care about Air Quality

AirGradient started as a volunteer project to help a school in Northern Thailand monitor the air quality in classrooms during the highly polluted burning season. From the beginning, we have worked with students and educators to building hardware to increase awareness in the area of air quality, to understand the health impacts of pollutants, and to empower the positive changes that can be made to reduce air pollution.

The experience and expertise that we gained designing and manufacturing our professional AirGradient ONE RESET Air Accredited Monitor has been put into our open-source / open-hardware air quality build instructions and kits.

The industry-grade sensor modules used in our open hardware monitors are the same modules found in pre-built monitors costing hundreds of dollars. As a result, you get highly accurate data quality, essential to having a reliable understanding of the air around you.

We’ve pledged 1% of sales to the preservation and restoration of the natural environment.