Hi Filip, thanks for your useful information here! There is a partly similar, German citizen science project. You can find it's English page here: luftdaten.info/en/home-en/ Their software for the ESP you can find on github, which includes different display to choose as well as the BME280 or others. However, there is no integration with MQTT, as they focus on publishing the sensors data online.
Fresh air for you!
We're a place where coders share, stay up-to-date and grow their careers.
We strive for transparency and don't collect excess data.