Ozone is a gas composed of three oxygen atoms, represented by the chemical formula O₃. This colorless and odorless gas occurs naturally in both the Earth's upper atmosphere (stratosphere) and at ground level (troposphere).
Formation of Ozone
- Stratospheric Ozone: Formed naturally through the interaction of solar ultraviolet (UV) radiation with molecular oxygen (O₂). UV radiation breaks apart O₂ molecules, and the resulting free oxygen atoms bond with other O₂ molecules to create O₃. (Source: US EPA, Utah Department of Environmental Quality, NASA Ozone Watch)
- Ground-Level Ozone: Not directly emitted into the air. It forms through chemical reactions between nitrogen oxides (NOx), volatile organic compounds (VOCs), and sunlight. (Source: American Lung Association, California Air Resources Board)
Ozone's Dual Nature
It's crucial to understand that ozone plays different roles depending on its location:
- Stratospheric Ozone (Ozone Layer): This layer is essential as it absorbs most of the sun's harmful UV radiation, protecting life on Earth. (Source: US EPA, NASA Ozone Watch, University of California, Berkeley)
- Ground-Level Ozone: This is a harmful air pollutant. It's a major component of smog and can cause respiratory problems and other health issues. (Source: US EPA, California Air Resources Board)
The essential building block for ozone in either layer remains the same: three oxygen atoms. However, the formation processes and environmental impacts differ significantly.
