Honestly, it seems like there's a long list of things to monitor:

* Radon * Carbon dioxide * Carbon monoxide * Nitrogen Dioxide * Sulfur Dioxide * Ozone * PM2.5, PM10 (any others?) * VOCs * Temperature * Humidity * Pressure

It is an opportunity for someone to make a "suite" sensor so you could scatter them around the house for good average measurements.

The air-q pro comes pretty close (I‘m thinking of buying it), but it‘s rather expensive and I haven‘t seen any reviews yet: https://shop.air-q.com/air-Q-Pro-air-analyser-14-sensors

Last time I looked into gas sensors (for measuring SO₂ and NO₂ which reach extreme levels in my area), they were $100+ each, depending on the gas it's measuring.

I think that kind of thing could get knocked down in price a bit with scale and inclusion in a sensor suite.

Have you looked at the View Plus (€300-ish)? It has PM2.5, CO2, radon, humidity, pressure and temperature. Also I believe it has multiple of some of the same sensors for better accuracy.

Way overpriced vs AliExpress but oh well.

https://www.airthings.com/en/view-plus

This thing looks amazing, and entire first batch is sold out!

Definitely going to pick one up when they are available. I might save a few bucks diong the DIY route, but at the end of the day, I would just buy 3-4 more shares of a vanguard thing, and have to tinker/maintain a grafana dashboard, where this thing is probably getting new apps/updates/features monthly.

I've been impressed with airthings, but less so recently.

Their app REALLY wants you to turn on tracking all the time, with a flashing unkillable banner at the top of the screen.