Well the people die in The Snow of Basidia because they have inhaled the spores and shortly after words they rive in a weakened state of agony coughing up blood as mushrooms burst out their eyes and chests and backs.
Bya would need protective gear to properly survive in the canyon in which the small town is located in and even more so if she wanted to help these people by tracking down and destroying the source of this so called "snow" and leave no traces of it behind so it can't regrow.
I mean has Bya even experienced death before and would seeing mushrooms instantly burst out of someone in agony but never dying scare her or has she seen death before and is use to it?