The Ozone Layer: A Visual Explainer
A clean, labeled flowchart showing how the ozone layer naturally forms in the stratosphere (the Chapman Cycle) and how it is depleted by human-made CFCs through a catalytic chlorine reaction.
📌 Revision Pointers
Ozone layer sits in the stratosphere, roughly 15–35 km altitude
Chapman Cycle: O₂ + UV-C → 2O; O + O₂ → O₃; O₃ absorbs UV-B (shields Earth)
CFC catalytic cycle: Cl• + O₃ → ClO + O₂, then ClO + O → Cl• + O₂ (chlorine regenerated)
One Cl atom can destroy over 1,00,000 ozone molecules — Antarctic ozone hole first identified in 1985
Montreal Protocol (1987) phased out CFCs globally; the layer is now recovering
This visual explainer maps the Chapman Cycle of natural ozone formation and the CFC-driven catalytic cycle that depletes it, ending with the global Montreal Protocol response.
💭 Conclusion
The Chapman Cycle vs CFC catalytic cycle contrast is a recurring Prelims favourite — anchor it to the Montreal Protocol (1987) as the fixed exam date.