Here you can find the code for two Air Quality sensor designs along with a work-in-progress configuration tool.
There are sensors based on the Heltec LoRa 32 device and the Wenos D2 Mini. You can find the source code for each in the devices folder. Each device folder also contains a cases folder where you can find printable designs for cases for the devices.
The Air Quality Sensor Drivers folder contains Python programs that can be used to communicate with SDS011 and XPH01 sensors. There is also a universal driver that can connect to a number of sensors directly over a number of serial ports and be for comparison and calibration.