Question

Which one of the following regions of atmosphere contains ozone? (a) troposphere (b) stratosphere (c) mesosphere (d) thermosphere

Short answer

The region of the atmosphere that contains ozone is the stratosphere (option b).

Step-by-step solution

Understanding the Layers of the Atmosphere

Let's first identify the different layers of Earth's atmosphere where the ozone layer could be located. The main layers are: troposphere, stratosphere, mesosphere, and thermosphere. Each has distinct characteristics and purposes.

Identifying the Role of Ozone

The ozone layer plays a crucial role in absorbing ultraviolet (UV) radiation from the sun, helping to protect life on Earth. Now, we must determine which atmospheric layer contains a significant concentration of ozone to fulfill this role.

Locating the Ozone Layer

The majority of ozone molecules are found in the stratosphere, which is the second layer of the atmosphere right above the troposphere. This region, known as the ozone layer, is located approximately 10 to 50 kilometers above Earth's surface.

Conclusion

From the information gathered, we can conclude that the stratosphere is the layer of the atmosphere that contains the ozone layer. This layer absorbs the majority of the sun's harmful ultraviolet radiation.

Key concepts

Ozone Layer

The ozone layer is a vital component within Earth's atmosphere, playing a critical role in protecting our planet from harmful ultraviolet (UV) radiation. This layer is rich in ozone (\( \text{O}_3 \)), a molecule composed of three oxygen atoms. Ozone absorbs the majority of the intense UV radiation from the sun, effectively reducing the amount that reaches the Earth's surface.
Without the ozone layer, the planet would be exposed to higher levels of UV radiation, increasing the risk of skin cancer and cataracts in humans, and potentially harming plants and animals. Since ozone is concentrated in a specific part of the atmosphere, understanding its location is crucial for recognizing its protective role.
The ozone layer is mainly situated in the stratosphere, which offers it a stable environment where it continuously performs its protective functions.

Stratosphere

The stratosphere is the second major layer of Earth's atmosphere, positioned directly above the troposphere and below the mesosphere. It extends from about 10 to 50 kilometers above the Earth's surface. This atmospheric layer is distinct for a number of reasons, one of which is the presence of the ozone layer.
Within the stratosphere, temperature increases with altitude, unlike the troposphere where temperature decreases with height. This temperature inversion is caused by the absorption of UV radiation by ozone, which releases heat and thus warms the stratosphere. Consequently, the stratosphere is a more stable region compared to the turbulent troposphere.
The stability of the stratosphere makes it an ideal place for the ozone layer to reside, allowing it to perform its essential role of filtering harmful UV radiation.

Ultraviolet Radiation

Ultraviolet (UV) radiation is a type of electromagnetic radiation emitted by the sun. It has a shorter wavelength than visible light, making it invisible to the human eye. UV radiation is categorized into three types based on its wavelength: UVA, UVB, and UVC.
- **UVA**: Has the longest wavelength and can penetrate deep into the skin. It can contribute to skin aging and wrinkling. - **UVB**: Can cause skin reddening and sunburn; it plays a key role in the development of skin cancer. - **UVC**: Has the shortest wavelength and is the most harmful, but is completely absorbed by the ozone layer in the stratosphere and does not reach the Earth. The ozone layer acts as Earth's natural sunscreen, absorbing most of the harmful UVC and some UVB radiation. This protective capability underscores the importance of the ozone layer in maintaining the health of living organisms by limiting their exposure to damaging UV rays.