Our Environment | Class 10 Science Notes

13.2.1 Ozone Layer and How it is Getting Depleted

Ozone (O₃) is a molecule made of three oxygen atoms. While oxygen (O₂) is essential for aerobic life, ozone at ground level is toxic. However, in the stratosphere, the ozone layer plays a vital role by absorbing most of the Sun's harmful ultraviolet (UV) radiation, protecting living organisms from damage such as skin cancer. Ozone forms when UV radiation splits oxygen molecules (O₂) into individual oxygen atoms (O), which then combine with O₂ to form ozone (O₃). This natural process maintains the ozone layer. However, since the 1980s, ozone levels have dropped sharply due to human-made chemicals like chlorofluorocarbons (CFCs), used in refrigerants and fire extinguishers. CFCs break down ozone molecules, thinning the ozone layer and creating 'holes' that allow more UV radiation to reach Earth. International agreements like the 1987 Montreal Protocol have aimed to freeze and reduce CFC production to protect the ozone layer.

🧪 Activity: Activity 13.4: Researching chemicals responsible for ozone depletion and evaluating effectiveness of regulations.

🔗 Connection: Leads to discussion on waste management and environmental pollution.