I've had 4 generations grow up in house with propane stovetop. My neighbors have several generations growing up with propane stovetops. Not a single lung disease or breathing issue except our 91 neighbor who smoked in the 80s.

What is really the factor here? Probably that we all have good ventilation and are not living in an urban area next to high pollution factors like highways or industrial complexes.

I hate to sound like a nimby or maga or whatever they are being called and I lean to the left living near Seattle but this just seems like another twisted study that should be of concern under certain contexts. Unfortunately right now having all electric appliances could be more costly as the grid is taxed more from EV usage, carbon taxes and Trumps attacks on renewables. It's a shitty situation but anything with a label of "This is deadly, here's a study for proof" should be met with some skeptism and serious research before your purchase.