Across much of Africa, sunshine is an everyday feature of life, yet many people pay more attention to heat exhaustion and dehydration than to another, invisible threat: ultraviolet (UV) radiation.
UV radiation cannot be seen or felt, but prolonged exposure can cause lasting damage to the skin and eyes. Its intensity varies according to location, season, altitude, cloud cover and time of day. The World Health Organization (WHO) considers a UV Index of 11 or higher ‘extreme’ and recommends sun protection whenever the index reaches 3 or above.
Exposure can be intensified when UV rays are reflected from surfaces such as sand, water and concrete. Although darker skin contains higher levels of protective melanin, it is not immune to damage. Excessive UV exposure has been linked to skin cancer, cataracts and immune-system damage, while the International Agency for Research on Cancer classifies solar UV radiation as a Group 1 carcinogen.
Cosmetic dermatologist Dr Paula Fakhre, a graduate of St. George’s University, said many people mistakenly associate sun protection only with beach outings.
‘UV exposure is something we live with every single day,’ she said, explaining that driving, walking between buildings or sitting close to a window can all contribute to cumulative exposure.
Fakhre said UVA radiation can penetrate glass and reach deeper layers of the skin without causing immediate pain. Over time, the damage can contribute to wrinkles, dark spots and premature ageing.
She advised people to choose broad-spectrum sunscreen suited to their skin type, apply sufficient quantities and reapply regularly.
Understanding UVA, UVB and UVC
The sun produces three types of UV radiation. UVC has the shortest wavelength and highest energy, but almost all of it is absorbed by the ozone layer before reaching the Earth’s surface.
UVB has a medium wavelength and penetrates the outer layer of the skin. It is the primary cause of sunburn and directly damages DNA in skin cells. It also contributes significantly to non-melanoma skin cancers, including basal cell carcinoma and squamous cell carcinoma.
UVA penetrates deeper into the dermis, where it can damage collagen and elastin. It contributes to photoaging, suppresses immune function and plays an important role in melanoma development. Unlike UVB, UVA passes through window glass and can expose people indoors or inside vehicles.
Understanding SPF
SPF, or Sun Protection Factor, measures protection against UVB and sunburn. SPF 30 blocks approximately 97 per cent of UVB rays, while SPF 50 blocks about 98 per cent. SPF does not, however, measure UVA protection.
Consumers should therefore look for products labelled ‘broad spectrum’ and, where available, a UVA rating or PA classification.
The protection stated on sunscreen labels assumes an application of 2 milligrams per square centimetre of skin. However, many people use only about half that amount, significantly reducing the protection they receive.
For the face and neck, the two-finger method is commonly recommended, while approximately 30-35 millilitres may be required for full-body coverage.
Sunscreen also needs regular reapplication because products can break down with sunlight or be removed by sweat, clothing and towel drying. No sunscreen is completely waterproof.
As UV Awareness Month highlights the importance of sun safety, experts are urging people across Africa to look beyond temperature and recognise the invisible risks posed by sunlight. Consistent use of broad-spectrum sunscreen, protective clothing, shade and other sun-safety measures can help reduce preventable skin and eye damage while allowing people to enjoy the outdoors safely.