Syllabus Edition
First teaching 2024
First exams 2026
UV Radiation (DP IB Environmental Systems & Societies (ESS))
Revision Note
Written by: Alistair Marjot
Reviewed by: Bridgette Barrett
UV Radiation Effects
The Sun emits electromagnetic radiation in a range of wavelengths, from low-frequency radio waves to high-frequency gamma radiation
Shorter wavelengths of radiation have higher frequencies
More energy damages living organisms
E.g. ultraviolet (UV) radiation
Effects on human health
Ultraviolet radiation from the Sun can have damaging effects on human living tissues
When excessive UV radiation reaches the surface of the Earth, it can lead to various health issues by damaging cells and tissues
UV Radiation Effects on Humans
Health issues caused by UV radiation | Explanation |
|---|---|
Cataracts | Prolonged exposure to UV radiation can contribute to the development of cataracts Cataracts cause clouding of the lens in the eye, leading to blurry vision and eventual vision loss if left untreated |
UV radiation affects cells | UV radiation has the potential to induce mutations in DNA during cell division When cells are exposed to UV radiation, it can lead to genetic alterations and mutations This can disrupt normal cell growth and increase the risk of developing cancer |
Skin cancer | UV radiation is a major risk factor for the development of skin cancer UV rays can damage the DNA in skin cells, leading to uncontrolled cell growth and the formation of cancerous tumours Prolonged or intense exposure to UV radiation, especially without proper protection, increases the risk of developing skin cancer |
Sunburn | When the skin is exposed to excessive UV rays, it triggers an inflammatory response as a defence mechanism Sunburned skin becomes red, painful and may blister, indicating damage to the skin cells |
Premature skin ageing | Chronic exposure to UV radiation accelerates the ageing process of the skin It can cause the breakdown of collagen and elastin fibres, leading to wrinkles, sagging skin and the development of age spots |
Effects on biological productivity
Harmful UV radiation reaching the Earth's surface affects plant growth and productivity
Increased UV exposure can lead to:
Reduced photosynthesis rates
Altered plant metabolism
Decreased crop yields
Exposure to increased UV radiation can affect other photosynthetic organisms, such as phytoplankton
Phytoplankton play a crucial role in aquatic food webs
They convert sunlight, carbon dioxide and nutrients into organic matter through photosynthesis
UV radiation damages phytoplankton by:
Causing DNA damage
Reducing photosynthetic activity and growth
This leads to a decrease in primary productivity in aquatic ecosystems
Reduced phytoplankton productivity can have cascading effects on higher trophic levels in aquatic ecosystems
Zooplankton, which feed on phytoplankton, have less food available
This affects their growth and reproduction
This, in turn, can impact higher-level consumers, such as fish and marine mammals
Organisms in these higher trophic levels rely on phytoplankton and zooplankton as food source
This can significantly reduce the biodiversity of aquatic ecosystems
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