Hi liaifat85,
Thank you very much for your help.
In fact, MQ137 and Grove - Multichannel Gas Sensor are smaller and cheaper but it needs higher technical skills to be installed. Besides, they are probably used for presence detection. As i said to PJ_Glasso, I need an out of the box industrial grade “plug and play” solution for a LoraWan NH3 measurement solution.
Franck 