Just stumbled across this thread. I’m working on something very similar so will be keeping an eye on your progress!
My plan is to use a raspberry pi zero in a IP rated case/box of some description. I’ll use cable glands and hose to draw air into the sensors. I’ve sourced a USB Power bank (~21ah I think) that supports pass through mode so combining this with a 20w solar panel should give me a good few days of running if not weeks in summer
I think I’ll need some ducting / manifold 3D printing to connect the hoses to the sensors for both inlet and exhaust.
Ive ordered the PMS7003 but still on the hunt for a NOX sensor / temperature and humidity.
Not sure about communication yet but for initial testing outside my house WiFi should be fine but might opt for 3G for deployment elsewhere.
Cheers
Andy