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World Ozone Day

World Ozone Day

  • In 1994, the UN General Assembly proclaimed 16 September as the International Day for the Preservation of the Ozone Layer, commemorating the date of the signing, in 1987, of the Montreal Protocol on Substances that Deplete the Ozone Layer (resolution 49/114).
  • The theme for this year is Montreal Protocol – keeping us, our food, and vaccines cool.

Ozone

  • It is composed of three atoms of oxygen (O3) and is a gas that occurs both in the Earth’s upper atmosphere and at ground level.

  • It occurs in two layers of the atmosphere.

  • Ozone can be “good” or “bad” for our health and the environment, depending on its location in the atmosphere.

  • The layer closest to the Earth’s surface is the troposphere. Here, ground-level or “bad” ozone is an air pollutant that is harmful to breathe and damages crops, trees, and other vegetation.

  • It is the main ingredient of urban smog.

  • The troposphere generally extends to a level about 6 miles up, where it meets the second layer, the stratosphere.

  • The stratosphere or “good” ozone layer extends upward from about 6 to 30 miles and protects life on Earth from the sun’s harmful ultraviolet (UV) rays.

Concerns with Stratosphere Ozone Layer

  • Ozone is produced naturally in the stratosphere. But this “good” ozone is gradually being destroyed by man-made chemicals referred to as ozone-depleting substances (ODS), including chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), halons, methyl bromide, carbon tetrachloride, and methyl chloroform.
  • These substances were formerly used and sometimes still are used in coolants, foaming agents, fire extinguishers, solvents, pesticides, and aerosol propellants.
  • Once released into the air these ozone-depleting substances degrade very slowly.
  • In fact, they can remain intact for years as they move through the troposphere until they reach the stratosphere.
  • There they are broken down by the intensity of the sun’s UV rays and release chlorine and bromine molecules, which destroy the stratospheric ozone.
  • Scientists estimate that one chlorine atom can destroy 100,000 stratospheric ozone molecules.
  • Even though we have reduced or eliminated the use of many ODSs, their use in the past can still affect the protective ozone layer.
  • Research indicates that depletion of the stratospheric ozone layer is being reduced worldwide. Thinning of the protective ozone layer can be observed using satellite measurements, particularly over the Polar Regions.

Depletion of Stratospheric Ozone and its Effect

  • Human health: Ozone depletion can cause increased amounts of UV radiation to reach the Earth which can lead to more cases of skin cancer, cataracts, and impaired immune systems.

  • Overexposure to UV is believed to be contributing to the increase in melanoma, the most fatal of all skin cancers. Since 1990, the risk of developing melanoma has more than doubled.

  • Food supplies: UV can also damage sensitive crops, such as soybeans, and reduce crop yields. Some scientists suggest that marine phytoplankton, which are the base of the ocean food chain, are already under stress from UV radiation.

  • Efforts to Check the Depletion of Stratospheric Ozone

  • Over 180 countries recognized the threats posed by ozone depletion and in 1987 adopted a treaty called the Montreal Protocol to phase out the production and use of ozone-depleting substances.

  • The 1987 Montreal Protocol on Substances that deplete the Ozone Layer and its succeeding amendments were subsequently negotiated to control the consumption and production of anthropogenic (ODSs) and some hydrofluorocarbons (HFCs).

  • Montreal Protocol deals with the development of replacement of substances, firstly hydrochlorofluorocarbons (HCFCs) and then HFCs, in a number of industrial sectors.

  • While HFCs have only a minor effect on stratospheric ozone, some HFCs are powerful greenhouse gases (GHGs).

  • The adoption of the 2016 Kigali Amendment to the Montreal Protocol will phase down the production and consumption of some HFCs and avoid much of the projected global warming increase and associated climate change.

India's effort on protecting the Depletion of Stratospheric Ozone

  • India, a signatory to the Protocol since 1992, has been proactive in compliance and played a key role in achieving the historic Kigali Amendment last year for phasing down Hydrofluorocarbons (HFCs), powerful greenhouse gases contributing to global climate change.
  • India is one among the few countries globally and a pioneer in some cases in the use of technologies, which are non-Ozone Depleting and have a low Global Warming Potential (GWP).
  • India has consciously chosen a path for environment-friendly and energy-efficient technologies while phasing out Ozone Depleting Substances (ODSs).
  • India has successfully achieved the complete phase-out of Hydrochlorofluorocarbon (HCFC)-141 b, which is a chemical used by foam manufacturing enterprises and one of the most potent ozone-depleting chemicals after Chlorofluorocarbons (CFCs)

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