I am able to find many journal articles confirming my observations that cooking produces significantly elevated indoor PM2.5 levels, many of which suggest it to be harmful, but I'm not finding anything about the relative impacts of the different substances that make up fine/ultrafine particles. People involved in this research seem to think it will require more study:
>“We know that inhaling particles, regardless of what they’re made of, is detrimental to health. Is it equally bad as inhaling exhaust from vehicle emissions? That we don’t know that yet,” [1]
Regardless, my sensor, at least, doesn't register water vapor as particulate. I can run an ultrasonic humidifier with distilled water to no effect on the measured PM2.5, or with tap water which will spike the particulates from the dissolved minerals.
1) https://www.theguardian.com/environment/2019/feb/17/cooking-...