Question

In the upper atmosphere ___ gets converted to ozone.

Answer 1

Most of the ozone production occurs in the tropical upper stratosphere and mesosphere. The total mass of ozone produced per day over the globe is about 400 million metric tons. The global mass of ozone is relatively constant at about 3 billion metric tons, meaning the Sun produces about 12% of the ozone layer each day.

An oxygen molecule is split by higher frequency UV light into two oxygen atoms :
O₂ + ℎν → 2 O•
Each oxygen atom then quickly combines with an oxygen molecule to form an ozone molecule:
O• + O₂ → O₃