Combined PM2.5 and NO2 sensor

I want to source a small box with

O CE marking
O Tolerance to humidity as found in a sheltered outdoor enclosure.
O A PM2.5 sensor
O An NO2 sensor
O A fan obviously.

O Any I can get of:
o SO2
o O3
o humidity
o temp
o PM2.5
o PM10

I want it to work outside in the UK - so very occasional -20C and +40C - normally -5 to 35.

I don’t need fancy accuracy - 10% sounds fine, maybe more if it’s all I can get.

I don’t want to have to externally calibrate it, or service it at less than 5 year intervals, if at all.

I have a Pi to talk to it with. Modbus would be lovely, but we can hack any protocol we need to

Any suggestions how I source such a thing?

Which Pi do you have?

Do you have battery / current-consumption constraints?

There’s a few gas sensors here, some of which do temperature and humidity as well. Could you buy one and start doing some testing?