Fungi can purify pollutants, but they can also emit mycotoxins that are extremely harmful to us. So you may have to wear a hazmat suit while the purification is

Fungi can purify pollutants, but they can also emit mycotoxins that are extremely harmful to us. So you may have to wear a hazmat suit while the purification is taking place... Yeah, that sounds just like Nausicaa. The manga it's based on (also by Miyazaki) is one of my all-time favorites.