Yeah, I think OP confused phlogiston theory [https://en.wikipedia.org/wiki/Phlogiston_theory https://en.wikipedia.org/wiki/Phlogiston_theory] with miasma theory

Yeah, I think OP confused phlogiston theory [https://en.wikipedia.org/wiki/Phlogiston_theory https://en.wikipedia.org/wiki/Phlogiston_theory] with miasma theory [https://en.wikipedia.org/wiki/Miasma_theory https://en.wikipedia.org/wiki/Miasma_theory]. The description of miasma theory by OP is more or less correct, it's just that the name is wrong.