Air-Sûr - Development and testing of an open-source prototype for monitoring internal air quality in spaces used by children. The aim of the Air-Sûr project is to develop an installation that continuously monitors the health conditions of an indoor environment based on measurements of a set of chemical, physical, and even biological parameters. Whatever the complexity of this set of parameters, the installation needs to satisfy several criteria: flexibility, modularity, scalability, accurate measurement, and cost optimization. It can be mobile and diagnostics based, or it can be fixed and integrated in a given space for the purpose of conducting long-term health monitoring. It could also potentially be used as part of a technical management system for the building. Moreover, it is a scalable system, which will be capable of integrating new sensors in the course of future development in different labs. Our overall goal is to develop an installation that is robust but affordable in terms of material, operating, handling, and maintenance costs.