Question

Ozone hole is maximum over (a) Africa (b) Europe (c) Antarctica (d) India

Short answer

(c) Antarctica

Step-by-step solution

Identify the hint in the question

The question is asking about a geographical area where the ozone hole is at its largest. The term 'ozone hole' generally refers to the thinning of the ozone layer over a specific area.

Recall geographical impact on the ozone layer

Historically, the region where the ozone layer has been recorded to have the most significant depletion is over the continent of Antarctica. This phenomenon is widely studied and documented by scientists.

Eliminate known incorrect options

Using knowledge of geographical impacts, eliminate regions less associated with the phenomenon of an ozone hole. Africa, Europe, and India are not commonly known for this depletion.

Select the most likely answer

Among the given options, the geographical area most affected by the thinning of the ozone layer, often referred to as the ozone hole, is Antarctica.

Key concepts

Ozone Layer Depletion

The ozone layer is like Earth's protective sunscreen, absorbing most of the sun's harmful ultraviolet radiation. However, this crucial layer has been suffering from depletion due to human activities. Ozone layer depletion refers to the thinning of this layer in the Earth's stratosphere. This happens because of chemicals like chlorofluorocarbons (CFCs), halons, and other ozone-depleting substances (ODS). When these substances reach the upper atmosphere, they release chlorine and bromine atoms upon exposure to ultraviolet (UV) light, causing the breakdown of ozone molecules.

When ozone molecules decrease, more UV rays reach the Earth. This not only harms living organisms but also contributes to global warming and climate change. Thankfully, global awareness and actions, such as the Montreal Protocol, have been put in place to reduce the emission of ODS, leading to gradual recovery signs in the ozone layer.

Antarctica

Antarctica, the southernmost continent, is a significant site in the study of ozone depletion. It is the coldest, driest, and windiest continent, mostly covered by ice. The unique climate conditions of Antarctica contribute to the ozone hole phenomenon observed over this region.

During the Antarctic winter, extreme cold creates polar stratospheric clouds (PSCs). These clouds provide a surface for chemical reactions that free chlorine from compounds in the atmosphere. When sunlight returns in the spring (September to November), this chlorine rapidly breaks down ozone molecules, resulting in the notorious ozone hole. This makes Antarctic spring the time when the ozone hole is at its largest.

Geographical Impact on Ozone

The geographical impact on the ozone layer is substantial and varies across different parts of the Earth. The phenomenon of the ozone hole is most pronounced over Antarctica because of the continent's specific atmospheric conditions.

• Extremely cold temperatures in the stratosphere lead to the formation of PSCs.
• These clouds facilitate chlorine-based chemistry, which depletes ozone molecules once sunlight returns.
• The Earth's wind patterns, known as the polar vortex, trap these chemicals over Antarctica, exacerbating the depletion.

While places like Africa, Europe, and India also experience some ozone depletion, it is less dramatic compared to Antarctica. The latter's unique environmental conditions make it a special focus in studies related to ozone layer health and recovery efforts.