Air quality

My friend Maya said: "[her friend] opened their air quality meter open to see what sensors were inside. IIRC it was a BME280-style sensor for temp, humidity & pressure and a second sensor that interpreted certain values to guesstimate CO2 & VoC. within certain conditions that approach can be quite reliable, but they can be confounded by certain environmental circumstances. somewhat like how optical smoke detectors are confused by dust & water vapour, I guess."

I am planning to do a teardown of my air quality meter.