Yes, UV light can destroy ozone, but it depends on the wavelength.
How UV Light Affects Ozone
UV radiation interacts with ozone in a complex way. While shorter UV wavelengths (less than 240 nanometers) can create ozone from oxygen molecules, longer UV-C wavelengths (specifically around 250-260 nm) are known to destroy existing ozone molecules. This is why a 253.7nm germicidal UV-C lamp, commonly used for disinfection, will destroy ozone. [1, 2, 5, 6, 10]
- Ozone Creation: Shorter UV wavelengths (<240 nm) possess sufficient energy to split oxygen molecules (O2), creating free oxygen atoms (O). These atoms can then combine with other oxygen molecules to form ozone (O3). [10]
- Ozone Destruction: Longer UV-C wavelengths (250-260 nm), such as those emitted by germicidal lamps, have enough energy to break down ozone molecules into oxygen molecules and free oxygen atoms. [1, 2, 5, 6]
The effect of UV radiation on ozone is wavelength-dependent. Different wavelengths have different energies, leading to either the creation or destruction of ozone.
This process is crucial to understanding both the natural ozone cycle in the stratosphere and the impact of human-made chemicals which deplete ozone. Some compounds, when exposed to intense UV radiation in the stratosphere, release chlorine or bromine atoms which catalytically destroy ozone molecules much faster than they are naturally created [3, 8, 9]. This is a major contributor to ozone depletion in the stratosphere.
In water treatment applications, UV light can be used to destroy ozone residuals after ozonation processes. This is because the energy required to destroy ozone is less than the energy required for the inactivation of pathogens. [5]
Summary
In summary, UV light's effect on ozone is determined by its wavelength. Shorter wavelengths create ozone, while longer UV-C wavelengths (around 250-260nm) break it down. This is a vital concept in various fields including atmospheric science and water treatment.
