Ozone occurs naturally in a layer of the atmosphere called the stratosphere. The ozone hole is a region of the stratosphere over Antarctica (and to a lesser degree over the Arctic) where the amount of ozone had decreased in the late 20th century, due to chemical reactions between ozone and human-made substances from things like aerosol spray cans and refrigerants. Ozone is the molecule O3 whereas oxygen is the molecule O2. Humans breath oxygen, but ozone leads to health hazards since it behaves like oxygen, but is significantly heavier than oxygen.
How is ozone different from oxygen?

1.) Ozone is light than oxygen
2.) Ozone is sifnificantly heavier than oxygen
3.) They are the same
4.) Ozone is totally healthy and good for you