Project Material on DEPLETION OF STRATOSPHERIC OZONE
DEPLETION OF STRATOSPHERIC OZONE
CHAPTER ONE
INTRODUCTION
BACKGROUND OF THE STUDY
The depletion of stratospheric ozone has become a topic of great concern due to its profound implications for human health, ecosystems, and the environment. Stratospheric ozone, often referred to as the ozone layer, acts as a protective shield, filtering out the majority of harmful ultraviolet (UV) radiation from the sun. However, human activities have led to the release of certain chemicals that have the capacity to destroy ozone molecules in the stratosphere, resulting in a gradual thinning of this vital atmospheric layer.
The discovery of the depletion of stratospheric ozone can be traced back to the 1970s when scientists began observing a decline in ozone concentrations above Antarctica. This phenomenon, known as the "ozone hole," attracted worldwide attention and sparked a collective realization that human actions were responsible for this environmental problem. The ozone hole phenomenon highlighted the vulnerability of the ozone layer and the urgent need to address its depletion.
The primary culprits behind stratospheric ozone depletion are human-made substances known as ozone-depleting substances (ODS). These include chlorofluorocarbons (CFCs), halons, carbon tetrachloride, and certain other chemicals. ODS are released into the atmosphere through various industrial, commercial, and domestic activities. Once in the stratosphere, these substances undergo chemical reactions that release chlorine and bromine atoms. These atoms then catalytically destroy ozone molecules, leading to a decrease in ozone concentration.
The consequences of stratospheric ozone depletion are far-reaching and multifaceted. Increased levels of UV radiation reaching the Earth's surface pose significant risks to human health. Prolonged exposure to UV-B radiation can cause skin cancers, cataracts, and suppressed immune systems. Moreover, UV radiation can have detrimental effects on ecosystems, affecting plant and animal life, particularly in marine environments. The productivity of phytoplankton, the foundation of