World Ozone Day (International Day for the Preservation of the Ozone Layer) is observed every year on 16 September. Declared by the United Nations General Assembly in 1994 (Resolution 49/114). The day marks the signing of the Montreal Protocol on Substances that Deplete the Ozone Layer (1987).
- Purpose: Raise awareness about the importance of the ozone layer, highlight international cooperation, and encourage global action against Ozone Depleting Substances (ODS).
Theme 2025
- “From Science to Global Action”
- Focus: How scientific findings led to policy measures and international cooperation, driving real environmental change.
- Celebrates the journey from early scientific warnings to global treaties and environmental impact.
Background
- Certain man-made chemicals (ODS) damage the ozone layer.
- Key culprits: Methyl bromide, methyl chloroform, carbon tetrachloride, halons, chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs).
- Halocarbons containing bromine have a much higher Ozone Depleting Potential (ODP) than those with chlorine.
Vienna Convention (1985)
- Adopted: 22 March 1985, signed by 28 countries.
- First global agreement to protect the ozone layer.
- Led to the Montreal Protocol (1987).
Montreal Protocol (1987)
- Aim: Protect ozone layer by controlling and eventually eliminating ODS.
- Structured around groups of chemicals, each with phase-out schedules.
- Consumption = (Production + Imports) – (Exports + Verified Destruction).
- Notable Exceptions:
- Metered Dose Inhalers (MDIs) for asthma/respiratory diseases.
- Halon-based fire suppression systems in submarines & aircraft.
- Phase-out Timelines:
- CFCs & Halons: Prioritized due to high ODP.
- HCFCs: Gradual phase-out (Developed nations: 2030, Developing nations: 2040).
- 2007: HCFC phase-out accelerated.
Implementation Success
- Developed and developing nations adhered to phase-out schedules, many ahead of time.
- Marked as one of the most successful international treaties.
Universal Ratification
- On 16 September 2009, both the Vienna Convention and Montreal Protocol achieved universal ratification – first treaties in UN history to do so.
Kigali Amendment (2016)
- Date: 15 October 2016, Kigali, Rwanda.
- Added Hydrofluorocarbons (HFCs) (strong greenhouse gases but not ODS) to phase-down list.
- India ratified in September 2021.
Ozone Layer (Good Ozone)
- Location: Stratosphere (10–40 km above Earth).
- Function: Shields life from harmful UV radiation.
- Benefits: Prevents skin cancer, cataracts, immune system suppression, and protects agriculture, forests, and marine life.
- Often described as “Earth’s Umbrella”.
Tropospheric Ozone (Bad Ozone)
- Found at ground level (short-lived, hours to weeks).
- Not directly emitted, but formed by reactions between:
- Volatile Organic Compounds (VOCs) (e.g., methane), and
- Nitrogen oxides (NOx) under sunlight.
- Harmful: Causes respiratory diseases, damages crops, and contributes to climate change.
Key Facts
- UN General Assembly established World Ozone Day in 1994.
- Montreal Protocol signed: 16 September 1987, effective from 1 January 1989.
- Ozone Hole Discovery: 1985 over Antarctica by British Antarctic Survey.
- ODS Phase-Out Achievement: By 2010, most countries had completely phased out CFCs.
- Global Fund Mechanism: Multilateral Fund (1991) assists developing countries in phasing out ODS.
- India:
- Party to Vienna Convention (1985) and Montreal Protocol (1987).
- Ratified Kigali Amendment in 2021.
- Implementing HCFC Phase-Out Management Plans (HPMP).
- World Ozone Day is also called Ozone Layer Preservation Day.