| Name | Type | Country | Components |
|---|---|---|---|
| Melpitz Research Station | Observational platform | Germany | 4 |
| Meteorological Observatory Hohenpeißenberg (DWD) | Observational platform | Germany | 3 |
| Meteorological Observatory Lindenberg | Observational platform | Germany | 1 |
| Milešovka | Observational platform | Czechia | 1 |
| Mobile Aerosol Laboratory | Mobile platform | Finland | 2 |
| Mobile FTIR spectrometer | Mobile platform | Germany | 1 |
| Montsec | Observational platform | Spain | 1 |
| Montseny Supersite | Observational platform | Spain | 1 |
| Multiphase Atmospheric Simulation Chamber (CESAM) | Atmospheric simulation chamber | France | 2 |
| Multiwavelength Raman Lidar | Mobile platform | Finland | 1 |
