Why is the smell of thunderstorms dangerous?

Have you ever smelled a specific thunderstorm? That's the smell of ozone, an allotropic modification of oxygen. The gas forms as a result of electrical discharges. 

 

Ozone (O₃) is an active substance and an aggressive oxidizing agent. Breathing air with a high concentration of ozone causes respiratory disorders. We can conclude that breathing the smell of thunder is harmful. 

 

Yet, there is the other side of the coin. The ozone layer of the atmosphere protects Earth from cosmic rays.