Environmental hierarchy as the third dimension of nanomaterial transformation science

Predicting nanomaterial (NM) fate requires more than structural snapshots and degradation curves. Current 2D models, which focus on space (structural change) and time (kinetics), provide valuable insights but remain incomplete. They cannot fully explain why identical NM behave differently across environments. Here, this Comment proposes a 3D framework that adds a critical third axis—environmental hierarchy—to capture transformations that are orthogonal to space and time.