How is ozone formed in the atmosphere?

• A. By chemical reactions involving carbon dioxide
• B. When O2 is split into single O atoms by sunlight or high voltage discharges
• C. Through volcanic eruptions and natural disasters
• D. By the decay of organic matter

Answer: (B)

Ozone is primarily formed in the atmosphere through a process that involves the splitting of oxygen molecules (O2) into individual oxygen atoms. This occurs when UV sunlight causes photodissociation, breaking the O2 molecules apart. These free oxygen atoms can then react with other O2 molecules to create ozone (O3). This reaction is fundamental to the formation of ozone in the stratosphere, where it plays a crucial role in absorbing harmful UV radiation from the sun, thus protecting life on Earth.

The other options do not accurately describe the process of ozone formation. While carbon dioxide, volcanic eruptions, and the decay of organic matter are significant in various environmental contexts, they do not contribute directly to ozone generation in the atmosphere. Understanding the specific role of UV radiation in the creation of ozone is essential for grasping the dynamics of atmospheric chemistry.