6.4.2—UV radiation danger
- Syllabus
- First assessment 2026
- Objective
- 6.4.2
- Level
- HL
Link UV Damage to Energy and Dose
UV harm depends on photon energy and dose; ozone blocks most UV-C and much UV-B, while UV-A reaches the surface more readily.
Higher-energy UV can damage DNA and tissue; total dose depends on intensity and exposure time. Ozone absorption changes the spectrum reaching organisms.
A short intense UV exposure can deliver similar dose to a longer weak exposure, but band and shielding still determine damage mechanism.
More biologically damaging UV-B/C can reach the surface; dose, behaviour and band determine actual risk.
UV index is not a direct measure of ozone alone; sun angle, clouds, altitude and surface reflection also matter.