Why the Ozone layer is 15-30km above the earth surface despite the fact that O3 is heavier than O2?

Question

Why the Ozone layer is 15-30km above the earth surface despite the fact that O3 is heavier than O2?

In: 42

Answer 1

Because O3 is mostly created by UV rays hitting O2 in the high athmosphere. Closer to the surface most UV is already shielded off