- Prevents UV radiation reaching the skin
- UVB (ultraviolet radiation) causes sunburn (and also enables vitamin D production)
- UVA causes wrinkles, brown spots (photoageing)
- Both UVB and UVA can contribute to the development of skin cancer
- SPF = Sun Protection Factor (the number of times longer you can stay in the sun before burning compared to wearing no sunscreen) indicates UVB protection
- The amount of UVB radiation that is filtered out varies with different SPFs:
- SPF 15 blocks 93% of UVB;
- SPF 30 blocks 96.7% of UVB;
- SPF 50 blocks 98.3% of UVB.
- Always check a product has UVA protection. It is not essential to have the Boots star rating, but if it has, look for 4 or 5 stars. The UVA in a circle is a marker of quality and indicates that the UV protection, specifically the critical wavelength, extends beyond 370nm.
- The critical wavelength (CW) is the point at which 90% of the absorption of UV takes place. 370nm is accepted as a minimum standard worldwide.
- Water resistant sunscreens are ideal for sports and outdoor activities
- Some vitamin D will still be produced when wearing sunscreen (other than total block)
- 40% of ultraviolet radiation reaches earth on a cloudy day
- UVA penetrates through glass – so wear sunscreen when driving
- Sun exposure occurs your entire life, not just during childhood
How to treat sunburn
- Cool bath
- Hydrocortisone cream (available without prescription)
- Drink extra water
- In case of blisters covering a large area or chills seek medical assistance
- Avoid sun until the skin is healed