Dvar Hashem Me'Yerushalmi: Beisa k'man d'malia dami

In the Bavli, Rashi in a couple of places says that beisa k'man d'malia dami is because a house is dark and its air is thick. The Yerushalmi Shabbos 4a clearly disagrees, as its sevara - which has no parallel in the Bavli - is that avir mechitzos k'mamasha. Which would even apply to an unroofed area.