"Under the conditions of the tap water humidification and the cold boiled water humidification, the mass concentration of particulate matters increases dramatically. But under the condition of the purified water humidification, particulate matters of each particle size have no obvious changes, and the mass concentration is lower."
The linked studies are about humidifiers, so perhaps different, but feels like for instance a rice cooker is not that far off. My gut feeling is that the particulate matter generated through "boiling water" is generally less dangerous than what you get from high-temperature frying (perhaps can depend on the water though). For instance based on https://www.nature.com/articles/s41586-020-2902-8 :
"We find that secondary inorganic components, crustal material and secondary biogenic organic aerosols control the mass concentration of particulate matter. By contrast, oxidative potential concentration is associated mostly with anthropogenic sources, in particular with fine-mode secondary organic aerosols largely from residential biomass burning and coarse-mode metals from vehicular non-exhaust emissions."
I'm not sure if your rice cooker example is entirely deceptive actually. I haven't read about or experimented much with particles from "boiling water" - so take my words with a big grain of salt. But, in https://chemistry.stackexchange.com/questions/105154/why-doe... it is pointed out that you might be seeing various things that were in the water (perhaps also from the rice). And I found https://blog.getawair.com/awair-investigates-how-your-humidi... quite interesting too, where they saw significant differences depending on what water they used. Seems they got similar results in https://www.scirp.org/html/7-6703158_71993.htm in which they write:
"Under the conditions of the tap water humidification and the cold boiled water humidification, the mass concentration of particulate matters increases dramatically. But under the condition of the purified water humidification, particulate matters of each particle size have no obvious changes, and the mass concentration is lower."
The linked studies are about humidifiers, so perhaps different, but feels like for instance a rice cooker is not that far off. My gut feeling is that the particulate matter generated through "boiling water" is generally less dangerous than what you get from high-temperature frying (perhaps can depend on the water though). For instance based on https://www.nature.com/articles/s41586-020-2902-8 :
"We find that secondary inorganic components, crustal material and secondary biogenic organic aerosols control the mass concentration of particulate matter. By contrast, oxidative potential concentration is associated mostly with anthropogenic sources, in particular with fine-mode secondary organic aerosols largely from residential biomass burning and coarse-mode metals from vehicular non-exhaust emissions."