What is ozone? How is it formed in the upper atmosphere? Explain the depletion of the ozone layer, its causes (especiall

Question

What is ozone? How is it formed in the upper atmosphere? Explain the depletion of the ozone layer, its causes (especially CFCs), and its harmful effects on human health and the environment.

Accepted Answer

Introduction to Ozone and its Formation
Ozone ($O3$) is a molecule formed by three atoms of oxygen. While it is a deadly poison at the ground level, it performs a crucial protective function at the higher levels of the atmosphere (stratosphere) by shielding the Earth from harmful ultraviolet (UV) radiations coming from the Sun. Formation: High up in the atmosphere, UV radiations split some molecular oxygen ($O2$) free into individual oxygen atoms ($O$). These free oxygen atoms then combine with molecular oxygen to form ozone ($O3$): $$O2 \xrightarrow{UV} O + O$$ $$O + O2 ightarrow O3$$ Depletion of Ozone Layer and Causes The thickness of the ozone layer in the stratosphere has been dropping sharply since the 1980s due to the release of synthetic chemical compounds into the atmosphere. The primary cause of ozone depletion is the widespread use of Chlorofluorocarbons (CFCs), which are used as refrigerants and in fire extinguishers. When CFCs reach the stratosphere, ultraviolet rays break them apart, releasing reactive chlorine atoms. A single chlorine atom can break down and destroy thousands of ozone molecules by converting them into oxygen, acting as a catalyst without getting consumed itself. Harmful Effects of Ozone Depletion Effect on Humans: Increased UV radiation reaching the Earth's surface can cause skin cancer, cataracts in eyes, and suppression of the human immune system. Effect on Environment & Ecosystems: It damages plant tissues, reduces agricultural crop yields by inhibiting photosynthesis, and kills plankton which form the base of aquatic food chains, thereby severely destabilizing marine ecosystems.

Our Environment

❓ Sibling Questions in this Chapter