For particulates, the Laseregg is the best I've found.
Apparently the laseregg 2+ measures VOC, but I'm not sure about that. From what I heard there are no VOC meters available at a consumer level. CO2 is the best proxy, because high CO2 means low ventilation, which prevents venting of VOCs.
* I am far more diligent about opening a window at my home and office. In winter I may open one a crack.
* I leave my bedroom door open at night
* I noticed I was getting extremely high AQI index readings when cooking. I was frying things in a pan after previously cooking something else in the same meal (meat, then sweet potatoes). I now wash in between, use coconut oil (less AQI readings) and am more diligent about opening the kitchen door if the AQU gets high
It's kind of like measuring weight. Once you have it stable, you don't really need to do anything. But, keeping the readings alerts you if something ever goes off track.
Also very useful to see that even openings in windows could make large and immediate differences.