The provided reference focuses on how human-produced substances deplete ozone, not natural causes. Therefore, the question should be rephrased to: What substances destroy ozone after being broken down in the stratosphere and after originating from human-made sources?
The answer is that chlorine and bromine molecules, released after the breakdown of man-made ozone-depleting substances (ODS) in the stratosphere, are the primary destroyers of ozone. These molecules are not the natural cause of ozone destruction, as the question implied but rather, result from a chain of events starting with human activity.
How It Happens:
- Ozone-Depleting Substances Released:
- Man-made chemicals like chlorofluorocarbons (CFCs), halons, and methyl bromide are released into the atmosphere.
- Migration to Stratosphere:
- These substances slowly migrate through the troposphere (lower atmosphere) to reach the stratosphere (upper atmosphere). This process can take years.
- Breakdown by UV Radiation:
- Intense ultraviolet (UV) radiation from the sun breaks down these ODS molecules in the stratosphere.
- Release of Chlorine and Bromine:
- The breakdown process releases chlorine and bromine molecules.
- Ozone Destruction:
- Chlorine and bromine act as catalysts in chemical reactions that destroy ozone molecules. A single chlorine atom, for example, can destroy thousands of ozone molecules.
Impact and Solutions:
- Impact: The depletion of ozone leads to increased levels of harmful UV radiation reaching the Earth's surface, causing skin cancer, cataracts, and damage to ecosystems.
- Solutions: The Montreal Protocol, an international treaty, has been successful in phasing out the production of ODS. This has led to a slow recovery of the ozone layer.
Key Takeaway
| Factor | Description |
|---|---|
| Primary Destructors | Chlorine and bromine molecules released from man-made ODS. |
| Process | Substances migrate, break down due to UV rays, releasing the destructive molecules. |
| Source | Primarily human-made chemicals, not naturally occurring elements acting directly on ozone. |
While the question asks for natural causes of ozone depletion, the provided reference explains the effect of human-generated pollutants on the ozone layer. The key takeaway is that it is the chemical breakdown of human-made substances that leads to the release of ozone-destroying molecules, and not a naturally occurring process independent of human intervention.
