Airgradient ONE and Open Air - Indoor and Outdoor Open Source Air Quality Monitor

“This article was originally published in German on Junicast by a community member. We are posting it in English with the permission of the writer.”

For many years, I have been searching for a suitable sensor to determine the air quality inside my house. Distances and weights are physical quantities that most people have a more or less well-developed sense of. However, this sense is often lacking for quantities like CO₂ concentration or fine particles (Particulate Matter / TVOC) in the ambient air.

For a good ten months now, I have been collecting metrics on the air quality of the most frequently used rooms in my house, both in the basement and in the living room. I regularly evaluate the data and have, of course, also learned about the different concentrations and what they mean. However, let me say this much in advance: The Airgradient One makes this much easier to understand by directly indicating the condition of the ambient air via colored LEDs. If the threshold values are exceeded, the LEDs light up red or even violet.

The Added Value of an Air Quality Sensor

In my experience, people are differently sensitive to, for example, unhealthy CO₂ concentrations in the ambient air. Especially when this sensitivity is less pronounced, an air quality sensor or air quality monitor can be a very welcome aid as it helps to optimise the ambient air and to read its condition. Optimised ambient air increases concentration and performance.

In this article, I cover both the Airgradient ONE (indoor) and the Airgradient Open Air (outdoor). They have the same technology installed, differing primarily in the housing and the missing display of the Open Air.

Integration / Self-Hosted

As an enthusiast for open source and data sovereignty, I prefer to collect and manage my data myself. This provides control. Not only is the granularity of the data higher, but I can also determine how long in the past I want to keep this data. In addition, there is the advantage that those mechanisms also work if the internet connection is not available. Therefore, it comes in very handy that the Airgradient devices already offer a Prometheus exporter. This makes integrating them into Prometheus / Grafana very easy.

What positively distinguishes Airgradient’s products from competitors is the focus on openness. This applies to both the hardware specifications and the software (firmware). The advantages are manifold. For example, the monitor can be replicated and made by anyone with free and public files, which is a very interesting project, especially for hobbyists. However, the savings potential is not huge. You are usually better off buying the devices in the AirGradient shop. However, you will have to accept a few days of waiting time for delivery, as they are shipped from Thailand.

Another advantage of openness is that you can contribute to the further development of the firmware yourself. You can also check how it works and ensure it contains no malicious components. This is anything but a given these days. Of course, you can also compile and upload the firmware yourself. Therefore, The device can be trusted much more than most other manufacturers.

Technical Details About Airgradient

The observations mentioned here are valid for the Airgradient One - Indoor Air Quality Monitor AND for the Airgradient Open Air - Outdoor Air Quality Monitor.

Tested with Firmware Version 3.1.13

Integration is achieved via WiFi. The setup is simple and well-documented (One / Open Air).

So far, however, there is unfortunately no support for IPv6. There is already a Feature Request for this. Despite its own IP address, the device does not have its own web server to control the device. Certain parameters can only be made via the Airgradient Dashboard. These include:

• Settings for display activity at night.
• Settings for brightness and mode of the LED status display.

Unfortunately, these options are also hidden in the location settings (Edit Location).

This, unfortunately, leads to point deductions. After all, there should be an API endpoint to change such things on-premise.

Most users will probably prefer to use the dashboard. I personally like to have my data in my home network. Airgradient rightly advertises exactly this adaptability because the metrics of the sensors also work without the sensor needing access to the internet. For several months, firmware has been available with a Prometheus Exporter built-in. A clear advantage of the Airgradient models over competitor products. From my point of view, solutions in this category are unusable if they require a working internet connection to function properly. Fortunately, this is not the case with AirGradient devices. For me, these were the most difficult criteria in choosing the best device.

Free Firmware!

In my view, it is particularly noteworthy that the device firmware is continuously being developed. This is not a given with conventional manufacturers. It seems that only profit maximisation is in their minds. Satisfied customers often seem secondary, if at all.

Even if the manufacturer Airgradient should no longer exist. The firmware’s source code is freely available and could continue to be developed even in such an unlikely case. This is sustainability thought through to the end. The landfills are full of products that should still be usable. Unlike those from Airgradient, devices are not only in a vendor lock, I would almost say in a vendor stranglehold. There, one is at the mercy of the manufacturer’s whims and potentially failing success. Unfortunately, many consumers still roam the market who mistakenly see an advantage in closed devices.

Airgradient Open Air Outdoor Device

Not only because collecting metric data is fun, but also because I want meaningful data about my external ambient air, an outdoor sensor, the Airgradient Open Air, has now been put into operation. It basically delivers the same data as the indoor sensor, but it is weatherproof and, therefore, intended for continuous operation outdoors. It also has no display and, unfortunately, does not tell the user anything about the condition of the air from the immediate environment when only looking at the sensor. However, Airgradient offers a very nicely presented dashboard that prepares and graphically displays the data.

Here is a representation of the fine particles in the ambient air over the last week. It is relatively easy to see that in colder weather, people heat more strongly and, accordingly, the outside air is more polluted. In addition to the particle graphs, there are others available for the other sensors mentioned above.

In my case, it was not particularly easy to find a suitable location for the sensor. It is powered via USB. Even if the power supply should deliver up to 2 amps at 5V, less is required in operation. I have measured values between 1 and 2 watts for power consumption, but mostly around 1.5 watts. I have already considered installing an outdoor PV system with a battery. However, the costs for this are between 150 and 300 euros, depending on how much tinkering you dare to do yourself. After all, the device is supplied with a 4m long USB-A to USB-C cable. This should help in some cases, but probably few people want to see cables in the garden.

Airgradient One (indoor)

For the sake of clarity, here are some impressions from the graphical representation of my self-hosted Grafana.

In addition, the sensor also immediately informs people on site about the development of the various measured values via colorful LED lights on the device. A small display also shows the measured values.

While some events such as cooking or burning candles can negatively change the fine particles in the air, the CO₂ concentration fluctuates the most. This can negatively affect well-being in various ways. Concentration problems are just one of the known side effects.

All the more helpful that you can be supported by this so far very reliable sensor to ventilate more often, for example. It is clear: Without the sensor, we would have ventilated significantly less often, especially in winter. We are very satisfied with the purchase and the result.