This contribution presents the results obtained within the KA2 Erasmus Plus project CO2 Monitoring in Schools for digital and green competences (CHANGE) [1]. The consortium, made up of an Italian Research Institute and four VET schools in Bulgaria, Italy, Romania and Spain, is developing, testing and optimizing a didactic pathway centered on Indoor Air Quality [2] in schools. The pathway combines digital skills, i.e. system integration, programming and data processing, with socially relevant topics such as IAQ monitoring, energy efficiency, greenhouse gases and climate change, raw materials and open data, in order to provide students with competences useful to meet the requirements of the labour market and to foster their critical thinking on scientific basis. The experimental section consists in the assembly of CO2 monitoring stations controlled by a Raspberry PI microcomputer with open source code …