AirGradient DIY Indoor & Outdoor Air Quality Monitor

Countless times I have mentioned that we need to monitor indoor and outdoor air quality. This is an essential step in order to have a holistic approach to air pollution that surrounds us in both environments. Unfortunately, not everybody can afford to buy two monitors but thanks to the community and AirGradient there are two DIY solutions that can help us monitor the air quality quite accurately and of course, manage the air we breathe better.

AirGradient’s DIY solution is more appealing than the competition for many reasons. First of all, you can buy directly the DIY Kit with all the electronic components from them including the PCB. The PCB is the board where we will deploy all the sensors, WiFi module, and display. That is a huge benefit because you don’t have to search on the internet and purchase the components one by one. The well-designed PCB will also help us keep the monitor neat and small without unnecessary cables. Secondly, Air Gradient’s DIY AQ Monitor is very customizable allowing us to build an indoor monitor with an NDIR CO2 sensor but another one without a CO2 sensor or display for the outdoor environment. If you don’t want temperature/humidity sensors you can easily omit them too, but I highly recommend them. Moreover, there is software support as a community of passionate people have been improving the firmware constantly. Finally, the solution comes with a web dashboard where you can manage all the monitors and take advantage of the histograms and tools like the alerts.

Additionally, the devices which are connected to the cloud and the dashboard can broadcast the measurements back to a separate display (Viewport) which allows us to see the air quality indoors and outdoors like in the example below. Isn’t that very cool?

It has been a long time since I soldered something, so I was very happy to build the monitor. I built two monitors by following the fairly easy instruction here. There is also a video with the instructions here by Jeff Geerling.

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Review: Airthinx IAQ for Businesses

In a previous post, I presented Airthinx IAQ for Homeowners and how an advanced AQ monitor can be used for indoor environmental monitoring. In this post, we will explore how we can use the same monitor but in business environments (offices, industrial buildings, food supply chains, etc).

We will focus on the tools present in the dashboard as it is one of the best dashboards you will find in the market, and we will learn how to get the most out of it.

Let’s begin with the Dashboard – Home. Here we can create various types of widgets and arrange them according to our preference. First, you can see that I have created a column with all the current measurements with small graphs of the environmental parameters. Right next to it, I always watch for the general AQ, PM2.5, and Humidity. Below I have more widgets with other graphs and values that I want to have a glance.

Dashboard – Home

Next, we can see the Map tab. Here we can locate all the available monitors in a high precision as the monitors come with a GPS module, however, we will see later that we can manually set the location of the device.

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Series of Innovators: SPEC Sensors


SPEC Sensors was founded in 2012 in the USA (California) by Dr. Joseph Stetter and Ed Stetter. Their gas sensors, analog and digital, are one of a kind as the technology and hard work has allowed them to minimize the sensor size to only 20x20x3 mm in order for gas sensing to become a part of our everyday lives. The company has foreseen that sensors of all types are going to be integrated into smartphones and other wearable devices, becoming an integral part of our everyday lives and building the Internet of Things (IoT).

IoT low-cost sensors are in my DNA as I believe they will allow us to understand environmental issues otherwise, we would have dismissed or we would not be aware.

Let’s read together what they have to share with us and reach a conclusion at the end.


  • Tell us a bit about your motivation in developing air quality sensors?

We saw the need and opportunity for low cost electrochemical sensors with good performance – before SPEC, high performance sensors were too expensive and too big to enable new applications in wearables and distributed monitors. SPEC was born out of the research driven by Eco Sensors / KWJ Engineering, Inc. led by Dr. Joseph Stetter.  We were able to build SPEC Sensors using modern technology in a new high performance plastic package.Read More »

What should schools do to prevent the spread of SARS-CoV-2 in classrooms

Masks provided decent protection against the SARS-CoV-2 but if a carrier of the virus (40% of them are asymptotic) stays inside a home/business for a long time then the chances of transmitting the virus are higher because some particles may escape.

According to experts the best way to prevent the spread of the virus is to keep introducing fresh air inside a room.

Unfortunately, most rooms don’t meet the recommendation of 8 air changes an hour for a 10 square meter (107 square foot) room occupied by 4 people. A clear example is a classroom that doesn’t meet the recommended ventilation rates. This is a common mistake across all schools in the world.

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Where are the Public Air Quality Stations?

In my city (Almeria, Spain) there are two stations that measure the local Air Quality.

Let’s analyze them and see if they are located in the correct places and if they feature the necessary instruments for measuring the AQI properly.

The Background

It is located in “El Boticario” a park 10km outside of the city center. The coordinates according to an official document from“Junta de Andalucía” are UTMX:554439 and UTMY:4080272, but they aren’t correct (Not so professional). The real coordinates are UTMX:554319 and UTMY:4080066. This station seems to work well although they don’t feed the data in real time to the public and quite often is down.

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