CO2 Lab is the indoor CO2 measurement laboratory, developed by Proambiente, dedicated to secondary school. The course combines elements of air quality and sustainability of electronic devices with digital making and skills.

The CO2 Lab project takes place on three main lines of activities:

1. Theoretical activity: understand the meaning of the CO2 concentration in the environment as an indicator of the healthiness of the environments, with particular reference to the spread of Coronavirus;

2. “Maker” activity: assembling a mini-station for real-time CO2 measurement with low-cost commercial components;

3. Educational activity: reuse of old hardware (smartphones) in a circular economy perspective, with particular reference to the problem of planned obsolescence.

A. The meaning of CO2 concentration in confined environments

CO2 concentration in indoor environments is a good indicator of the correlation between number of persons and air changes. Furthermore, it is well known that the presence of an excessive number of people in a poorly ventilated environment may increase the spread of Coronavirus (see ISS COVID-19 report no. 5/2020 Rev. 2).
For such reason, even if CO2 is not a harmful or pollutant compound, it can be considered as an indicator of indoor air quality, concerning the insufficiency of air changes. On the other hand, the good news is that CO2 is nowadays easily measurable with low-cost sensors, which ensure a reasonable degree of accuracy in the monitoring of poorly ventilated environments.
CO2 outdoor concentration is currently in the order of 415 ppm (parts per million), but it is constantly increasing due to anthropogenic emissions caused by fossil fuels. The main concern about the increase of CO2 concentration in outdoor environment is related to greenhouse effect and climatic changes. In indoor environments, the issues are different. Since CO2 is emitted by human beings through their breath, in crowded spaces and with insufficient ventilation the concentration of CO2 may increase up to several thousands ppm. Such concentration values, even if strictly not harmful for humans, can cause symptoms such as reduced concentration, fatigue and a sense of exhaustion.
Moreover, since the beginning of the COVID-19 pandemic crisis (February 2020), a high concentration of indoor CO2 - especially in public environments - must be seen as an alarm bell for an excessive crowding of the confined environment, also related to internal air changes. It is well known that this phenomenon must be avoided, to reduce the likelihood of inhaling droplets produced by potential carriers of Coronavirus.

The recommendation to ventilate indoor environments, such as school classrooms, is therefore absolutely valid and correct, and remains a good practice regardless of the presence of instruments for CO2 concentration measurement. However, in order to avoid an excess of ventilation, which brings a higher energy consumption for heating (or cooling) the rooms, a low-cost system for real-time monitoring of CO2 concentration may represent an useful aid.


B. Maker’s day

During the last few years, a constant growth in the availability of integrated electronic systems came out, with an impressive amount of possible uses and reasonably low costs. These systems are used by the so-called “makers”, people deeply involved in the development of robotic, domotic and multifunctional systems, and IoT (“Internet of Things”) applications. A typical example is the range of "Raspberry Pi", micro-computers, having the size of a credit card and equipped with all the features of a real PC: video output to connect a TV or a monitor, USB ports to connect peripherals, storage memory (based on micro-SD cards), WiFi and BluetoothTM communication capabilities. The range of Raspberry Pi, originally developed at the famous University of Cambridge (UK), goes from the recent Raspberry Pi 4 (equipped with a powerful processor and up to 8 GB of RAM) at a cost of about € 100 including accessories, to the tiny Raspberry Pi Zero W, which is the basis of this project. The Zero W version has a limited memory and a slower processor, however sufficient for the proposed application, and is equipped with WiFi and Bluetooth at a cost of about € 15-20 (due to the current crisis of electronic components supply).

It is important to point out that these micro-PCs, thanks to the Linux operating system, are also able to perform as web server, thus allowing the visualization of dynamic web pages with the most different contents. Furthermore, being based on the widespread and Open Source Debian Linux distribution, they can be programmed in different languages, including the powerful Python language used for this project, supported by a large community of developers and by many components available with Open Source licenses. The experimental set-up integrates a CO2 detector (model SCD30 produced by Sensirion) which, by means of the non-dispersive infrared absorption principle (for an introductory explanation see for example: allows to measure CO2 concentration and send the values to the Raspberry Pi micro-PC via a specific two-wires communication bus.


C. A small step vs. planned obsolescence

A huge amount of displays for Raspberry Pi systems is available on the market, from small liquid crystal displays to large 9” LED displays, up to ePaper displays (electronic paper) typical of electronic books. But why should we buy a display for our system? Couldn’t we use something we already have?
We all probably have an old smartphone at home, maybe a model from 7-8 years ago, which has fallen into disuse as it no longer runs the most recent apps or the latest versions of Android (or iOS). However, these "electronic residues", subject to the so-called planned obsolescence, can be considered as real micro-computers equipped with touch-screen display, WiFi, speaker and battery, still fully functional but abandoned in a drawer.
In the circuits and in the screen of a mobile phone we can find different materials composed of elements that are considered “critical”, since they are scarcely present in the Earth surface. Their massive use in electronics led to a difficulty in supplying and to an inevitable increase in the costs of these raw materials. One possibility to reduce the demand for these elements is the reuse of obsolete mobile phones in applications where high performances are not required.
The proposed project allows to circumvent planned obsolescence by giving new life to old smartphones or tablets: it will be sufficient a WiFi connection to the monitoring station and a web browser to use the CO2 Lab WebApp, to display real-time data, receive audio alerts in case of high CO2 levels and download the raw data of the daily trend of CO2 concentrations in table format.
We therefore decided to design our CO2 monitoring station around the idea of using an old smartphone model as a display and user-interface.
So now: look for your old phone, dust it off, plug in the charger, and ... here we go!


D. The pathway

The didactic pathway is addressed to secondary school students. It starts with the search for old used smartphones. This preparatory activity, carried out by the students on their own, aims to generate a reflection on the perceived obsolescence of mobile phones. The educational activities consist of a seminar to present the issues and a practical activity of CO2 measurements in the classrooms in various conditions, such as open/closed windows, number of students and cleaning of the classrooms. The course is completed with the data analysis and the drafting of a laboratory report produced by the students, and with an overall evaluation of the pathway. Topics such as sustainability, making and digital skills, make CO2 Lab particularly suitable for PCTO and civic education in secondary schools.



E. CO2Lab system


Based on an idea of: Stefano Zampolli (IMM-CNR Researcher)

Ispired by:  Progetto “CO2-Ampel” di Umwelt Kampus Birkenfeld, Germania

Prototype design: Francesco Suriano (Proambiente Researcher)

WebApp :  Francesco Marucci (Proambiente Technologist)

Percorso formativo:  Marica Canino (IMM-CNR Researcher)

Info & Contacts: This email address is being protected from spambots. You need JavaScript enabled to view it.

Detailed information about Indoor Air Quality and Covid-19 issues



Coordinator: Proambiente S.C.r.l. and IMM-CNR - Institute for microelectronics and microsystems


Schools involved

- Istituto Professionale IPSIA "G. Ferraris", Catanzaro - The laboratory was carried out in May 2022

- Istituto Tecnico Tecnologico ITT "B. Chimirri", Catanzaro - The laboratory was carried out in February 2022

- Liceo Scientifico Statale "A. Righi", Bologna - The laboratory was carried out in February 2022

- Liceo Ginnasio Statale "G. Galvani", Bologna - The laboratory was carried out in February 2022

- Istituto di Istruzione Superiore IIS " Belluzzi-Fioravanti", Bologna - The Laboratory will take place in April 2022


Duration: 2021/05/01 – 2022/04/30 (12months)

Project Self-financing by Partners


Download this file (CO2-Lab_v2-7.pdf)Progetto COOL - CO2Lab[ ]1153 kB