I'm asking myself if building a DIY setup or buying something like Airthings Wave Plus will actually track these compounds at decent accuracy - and if anyone here has gone down this rabbit hole for family health?

From what I've gathered, consumer devices hit acceptable accuracy for CO2/temp/humidity but PM2.5 is hit-or-miss, and VOC readings are more "relative change indicators" than absolute values..

DIY with Home Assistant is more work/fun yes but again only gets similar accuracy AFAIK (with potentially better automation)..

You can (within reason) calibrate these cheap CO2 easily with esphome and an outdoor air reference point overtime. I’ve had to do it for thermometers as well.