For hardware used, see here:
https://www.airgradient.com/open-airgradient/shop/#!/DIY-Pro-Kit-version-3-7/p/447362982/category=0
With added SGP41:
https://www.airgradient.com/open-airgradient/shop/#!/SGP41-TVOC-Module-for-PRO-Kits/p/504083522/category=0
For detailled build-instructions:
https://www.airgradient.com/open-airgradient/instructions/diy-pro-v37/
This is run with Home-assistant: https://www.home-assistant.io/
and the ESPHome integration: https://esphome.io/
Initial config taken from here: https://github.com/ajfriesen/ESPHome-AirGradient/