In our lives , we are expose to :
Air Pollution
Air pollution is the presence of natural and artificial substances in the air that affect the health of humans and other organisms. A person continuously exposed to polluted air may eventually develop lung problems.
Global Warming
Global Warming (Global Climate Change) is a scientific proposal that the Earth's average atmospheric temperature is currently warming up due to increasing levels of Greenhouse Gases and/or other factors.
So we need O3 to protect us.