Question

Ozone layer is present in

• A. Troposphere
• B. Stratosphere
• C. Ionosphere
• D. Exosphere

Hint:

"Good up high, bad nearby."
Remember: Stratosphere = Good ozone (Protects from UV).
Troposphere = Bad ozone (Pollutant).

Answer 1

The Correct Option is B

Step 1: Understanding the Question:
The question asks to identify the layer of the Earth's atmosphere that contains the highest concentration of ozone (\( O_3 \)).
Detailed Explanation:

• Atmospheric Layers:
The atmosphere is divided into several layers: Troposphere (0-12 km), Stratosphere (12-50 km), Mesosphere, Thermosphere (includes Ionosphere), and Exosphere.

• The Ozone Layer:
Approximately \( 90\% \) of the Earth's ozone is located in the Stratosphere, primarily between 15 and 35 kilometers above the Earth's surface.
This is often called the "ozonosphere."
Ozone in this layer is formed by the action of ultraviolet (UV) radiation on oxygen molecules (\( O_2 \)).

• Biological Importance:
The stratospheric ozone layer is vital for life on Earth because it absorbs most of the Sun's harmful ultraviolet-B (UV-B) radiation.
Without this protection, UV radiation would cause DNA damage, skin cancers, cataracts, and severely inhibit photosynthesis in plants and phytoplankton.

• Tropospheric Ozone:
Note that ozone can also be found in the Troposphere, but there it is considered a pollutant and a major component of smog, often referred to as "bad ozone."

Step 3: Final Answer:
The protective ozone layer is located in the Stratosphere.