What would happen if the ozone layer disappeared?
If the ozone disappears, then ultraviolet from the sun in all of its 3 forms will enter. The three forms are UV-A, UV-B and UV-C. UV-B and UV-C are very dangerous while UV-A can actually be beneficial for us.
The purpose of ozone is to protect living organisms from the excessive UV radiation which can interfere with the DNA and cell division processes in animals and humans leading to mutations, skin cancer, cataract in eyes, weakness in human immune response.
It can also affect the marine food chain since it can kill plankton in oceans. Since plankton form the basis of the marine food chain, it will in term affect its predators.
It can also affect bacterial processes such as cyanobacteria. Cyanobacteria convert nitrogen in air to nitrates in soil for crops. So for crops such as corn and rice, humans will be greatly affected by the lack of food supply it will bring.
UV can also affect the polymers such as pure PVC (polychloride) which can break down in ultraviolet light.