A common scene in any summer is seeing how people arrive at the beach, stick their umbrella in the sand, spread their towel or put their chair under the shade and breathe a sigh of relief because they think that this way they won’t get burned. The problem comes when you get home and, after taking a shower, you can clearly see how your skin is burned.
The culprit. This situation, which is more common than we think, is not the fault of the material the umbrella is made of or even the protection factor assigned to these products, but rather the problem is in the sand itself and the rebound effect that the Sun’s rays have.
The experiment. To understand what is happening here, we have to go to a great study published in 2017where researchers took 81 participants with sun-sensitive skin to a sunny Texas beach. They were left in this environment for 3 and a half hours at midday, but with the difference that one group of them only used a standard beach umbrella as protection and another group only used sunscreen with an SPF 100 factor without seeking shade.
The results were devastating, since 78% of the participants who were under the umbrella developed sunburn, compared to 25% in the group that used the cream. Although if we look at the total number of injuries, the difference is even more overwhelming, as 142 incidences of sunburn were recorded under the umbrella, compared to only 17 in the sunscreen group.
How is it possible? For many people, it makes no sense to burn their skin if they are constantly in the shade, but the answer to this lies in albedo, which is a metric that defines the percentage of radiation that is reflected by a specific surface. And ultraviolet light not only ‘falls’ from the sky in a straight line hitting us, but it also bounces off the ground and impacts from any direction.
For example, we know that beach sand reflects between 15% and 20% of the UV radiation it receives, a figure that is much higher than that reflected by asphalt, which is around 2%. Although all of these remain ‘nothing’ if we compare it with snow, which is undoubtedly almost like a mirror, since it reflects a spectacular 85% of ultraviolet rays.
You have to combine it. With all this data we should not fall into the thought that the umbrella is completely useless, but we should be aware of the importance of using sunscreen as soon as we leave home to prevent this radiation from affecting our skin. And logically, also combine it with the umbrella on the beach to achieve these two protection systems.
It’s not just the beach. It is increasingly common to see people on the street who are walking with their umbrellabut here you are not exempt from suffering some burns because, as we have seen, even asphalt can reflect ultraviolet radiation. That is why sunscreen is not only an item that should be used when we go to the beach or pool, but in any situation where the UV index is high.
Images | Engin Akyurt
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