Collaborative industry/academic ANR project between two industrial (ISORG, Efficacity) and three academic partners (LCPO, IMS, XLIM). We propose original sensors based on microwave transducers operating at ambient temperature in order to address some of the issues related to monitoring the quality of polluted air related to exhaust gases due, for instance, to transports and industrial activity. This has led to specifications in particular for certain harmful vapors such as nitrogen dioxide (NO2), sulfur dioxide (SO2) and ozone (O3) as highlighted in the French regulations.