NAIROBI, Kenya, Aug 12 – As ultraviolet (UV) exposure becomes an increasingly important public health concern in Africa, dermatologists are urging consumers to look beyond sunscreen’s headline SPF number and understand the different types of radiation reaching the skin.
Unlike heat, UV radiation cannot be seen or felt, meaning people can accumulate significant exposure even when temperatures are moderate. The World Health Organization recommends sun protection when the UV Index reaches 3 and classifies levels of 11 and above as extreme.
The risk is particularly relevant in parts of Africa where strong sunlight is common. UV exposure can vary with altitude, season, cloud cover and time of day, while surfaces such as water, sand and concrete can reflect radiation and increase exposure.
While melanin provides some natural protection, darker skin is not immune to UV-related damage. The WHO links excessive exposure to skin cancer, cataracts and damage to the immune system, while the International Agency for Research on Cancer classifies solar UV radiation as a Group 1 carcinogen.
“People think sun protection is for the beach, but UV exposure is something we live with every single day,” said Dr Paula Fakhre, a cosmetic dermatologist and St. George’s University graduate.
Fakhre said routine activities such as commuting, walking outdoors and sitting near windows can contribute to cumulative exposure, particularly from UVA radiation, which can pass through glass.
Understanding the distinction between UVA and UVB is important because the two affect the skin differently. UVB is the primary cause of sunburn and directly damages DNA in skin cells, while UVA penetrates deeper into the skin and is associated with photoaging and other forms of long-term damage.
UVA accounts for the majority of UV radiation reaching the Earth’s surface and can remain relevant even when there is no visible sunburn.
This also exposes a limitation in the way many consumers interpret sunscreen labels.
SPF, or Sun Protection Factor, primarily measures protection against UVB-induced sunburn. SPF 30 filters about 97 percent of UVB radiation under standard testing conditions, while SPF 50 filters about 98 percent. The rating does not, by itself, indicate the level of UVA protection.
Consumers therefore need to look for products labelled “broad spectrum” or carrying an additional UVA rating. The PA system, widely used in Asian markets, is one such indicator, with ratings ranging from PA+ to PA++++.
Application is another weakness in everyday sunscreen use. SPF testing assumes an application of about 2 milligrams per square centimetre, while people commonly use less, reducing the protection they actually receive.
Sunscreen also does not provide unlimited protection. Sweat, swimming, rubbing and towel drying can remove it, making reapplication necessary. No sunscreen is completely waterproof.
The choice between chemical and mineral formulations also involves trade-offs rather than a simple better-or-worse distinction. Chemical filters absorb UV radiation, while mineral filters such as zinc oxide and titanium dioxide work primarily by absorbing, scattering and reflecting radiation. Formulation, skin type, comfort and consistent use can therefore matter as much as the type of filter.
The wider message for consumers is that sun protection should not be treated solely as a beach-day precaution. Clothing, shade, hats, sunglasses and limiting exposure during periods of intense UV can complement sunscreen.
As awareness campaigns draw attention to UV exposure, the challenge is less about choosing the highest SPF number and more about understanding what the product protects against—and using it correctly and consistently.
