One thing that frustrates me about air quality is that we have sensors for various types of gasses, but when it comes to particulates, the sensors are just telling you the size. The composition of the particle has to make a huge difference in terms of the effects. Metal dust from a brake pad or rubber from a tire must do very different things to your lungs than vegetable oil.

If you look at how a CO2 sensor works [0], you see that it is tuned for a specific material. Characterizing any possible material would be the job of a gas chromatograph [1], which are typically an industrial/scientific instrument as opposed to a more limited mass produced device. Maybe one day the cost (both material and ongoing maintenance) will be low enough to have in one's home.

0. https://www.co2meter.com/blogs/news/co2-carbon-dioxide-detec...

1. https://en.wikipedia.org/wiki/Gas_chromatography%E2%80%93mas...