) is a molecule made of three oxygen atoms. While ozone near the ground (tropospheric ozone) is a harmful pollutant, stratospheric ozone is essential for survival. Depletion occurs when certain manufactured chemicals—primarily , halons , and carbon tetrachloride —reach the stratosphere and are broken down by UV light. This release of chlorine and bromine atoms triggers a chain reaction: a single chlorine atom can destroy over 100,000 ozone molecules before it is removed from the atmosphere. Major Causes of Thinning
A 1% decrease in ozone can lead to a 2% increase in harmful UV-B radiation reaching the surface.
: Many crops, including rice and soybeans, are sensitive to UV radiation, which can stunt growth and reduce yields. A Global Success Story: The Montreal Protocol ozone layer depletion pdf free download
: Used in refrigerators, air conditioners, and aerosol sprays.
In 1987, the world responded with the Montreal Protocol, an international treaty designed to phase out the production of ozone-depleting substances. It is widely considered the most successful environmental agreement in history. Due to global compliance, the ozone layer is showing signs of recovery and is expected to return to 1980 levels by mid-century. ) is a molecule made of three oxygen atoms
: While rare, massive volcanic eruptions can temporarily accelerate the chemical reactions that deplete ozone. Consequences of a Thinning Shield
: Increased exposure causes higher rates of skin cancers (melanoma), cataracts, and weakened immune systems. This release of chlorine and bromine atoms triggers
: Methyl bromide, often used for soil fumigation, is a potent ozone-depleter.