What is the function of ozone in the atmosphere?
as you can see by the figure under, sun radiation covers all the field of wavelength included UV. well Uv radiation has an energy so strong that it can break the bonds of the biological molecules that form our body and if it wouldn't arrived filtred, life on earth wuold be impossible.
we can tolerate only radiation over 400 nm. Ozone which lies in stratosfere has the task to absorb radiation under this wavelenght.
attention instead!. Ozone is toxic if you find it in the lower strate of atmosfere and you cannot breath it