Thank you for this. As someone who lived through the hellish airscape of last year's Australian bushfires, and spent quite a bit of time discussing, advising, and publicizing air quality concerns, efforts like this are sorely needed.

At this point I've been recommending people buy PurpleAir monitors for grassroots air quality monitoring, but this looks like a really great DIY option.

I'm particularly excited about the CO2 sensor, since until this point I've been focused mostly on PM2.5 and PM10 particles, but am really keen to figure out if my stuffy apartment bedroom (and baby's room) is reaching too high CO2 levels at night (with corresponding headaches and impact on cognitive performance).