2.6 Effects of Ozone Depletion: UV Radiation

Ultra Violet (UV) radiation can be classified into three component wavelengths as a means of better understanding the potential negative impacts it has on human and environmental health.

These UV wavelengths include:

• UV-A (long wave: 380-315 nm)
• UV-B (medium wave: 315-280 nm)
• UV-C (short wave: < 280 nm)

Human Effects

The detrimental effects resulting from UV-A are negligible at best, but can contribute to:

• Skin wrinkling
• DNA damage
• Skin cancer in extreme circumstances

UV-A rays typically penetrate human skin the deepest but, are not a known cause of sunburn.

The wavelength of greatest concern to humanity is UV-B, the primary cause of skin cancer – but the reality is they all have the potential to damage living tissue that significantly leads to the aging of skin.

UV-C rays, which are extremely harmful to humans, are completely screened out by the ozone layer at around 35 kilometers in altitude.

As a result, little attention is given to UVC radiation.

Environmental Effects

UV-B rays can also negatively impact terrestrial ecosystems by reducing:

• Crop yields
• Altering species composition and competition
• Reducing the capacity for photosynthesis
• Increasing the risk of disease
• Stunting growth
• Similarly, aquatic studies have shown that phytoplankton, which form the basis of most aquatic food chains, are highly sensitive to increased levels of UV-B radiation as it reduces their mobility and ability to photosynthesize
• In addition to the natural environment, the built environment is also susceptible to damage from UV light specifically polymer plastic

 I.e. polyvinyl chloride (PVC), typically found in window frames, can undergo a variety of chemical changes including discolouration (yellowing) and loss of structural integrity, which leads to cracking.