After months of sadness and rain, the sun is finally here, and with it these celebrities ultraviolet rays (UV) you should be careful. Indeed, excessive doses of ultraviolet rays attack skin cells and can cause irreversible damage, such as the appearance of skin cancer.
according to National Cancer Institute Between 1990 and 2023, the number of new cases of skin cancer has doubled. Therefore, it is important to protect yourself by applying appropriate sun protection measures.
Chemical and physical filters, sunscreen “screens”
When we talk about sun protection, we generally think sun creams. But how do they work, exactly?
It’s worth mentioning before continuing The composition of UV rays. There are three types of UV rays in sunlight: UVA, UVB, and UVC. As it passes through the atmosphere, all UVC and most UVB are absorbed by the ozone layer. UVA alone is not effectively filtered by the atmosphere and accounts for 95% of UV rays reaching the earth’s surface.
UVA has long-lasting effects, plays a major role in premature skin aging and increases the risk of skin cancer. UVB rays reach the epidermis and cause sunburn and tanning in a short period of time. However, the accumulation of their actions contributes to premature aging of the skin and the development of cancer in the long run.
sun cream blocks UV rays before they reach the skin. It contains UV filters that can be of two types: chemical (organic) filters and physical (mineral) filters.
Organic filters, molecules containing carbon atoms, absorb UV rays instead of the skin and convert the received radiation energy into low heat, which is then dissipated. The advantage of these filters is that they are transparent after being applied to the skin. However, organic filters are not always effective at all wavelengths of the UV spectrum. To obtain adequate protection, often they need to be combined. Therefore, a sunscreen product may contain several complementary chemical molecules as indicated on the label.
Mineral filters act as a physical barrier by reflecting UV rays off the skin, somewhat like a mirror. These filters are mainly made of oxides such as zinc oxide and titanium dioxide. Mineral filters have an advantage less allergenic and more active at all wavelengths Like UV, organic filters. However, they often form a white film on the skin, which can be unpleasant.
In addition, some of these mineral screens are controversial due to their formulation in nanoparticle form (to prevent a white appearance on the skin). We will return to this point later.
How Much UV Rays Are Avoided by Sunscreen?
Either way, as the name suggests, these solar filters act as a “screen” and don’t block all of the sun’s UV rays. Some of these rays can pass through sunscreen and reach our skin. We use the Sun Protection Factor, or SPF, to measure the amount of UV rays a sunscreen blocks (note that the abbreviation SPF is sometimes displayed on the packaging). The higher the SPF, the less UV rays can pass through the sunscreen.
And is applied correctly (in amount and frequency), a sunscreen with an SPF of 15 absorbs 93% of UVB and an SPF of 30 filters out 97% of UVB. Recommendation of the European Commission. And finally, the level of protection between an SPF 30 and SPF 50 sun product (Blocks 98% of UVB) will be very close at the end…
But even though sunscreens are very effective under optimal conditions of use their effectiveness decreases with time and the amount of cream applied, friction, perspiration, water etc. that remove it. varies depending on several parameters such as
Some chemical filters are toxic to corals
On the other hand, a number of scientific studies show that sunscreen is not neutral for the environment. Indeed, UV filters have a harmful and aggressive effect on coral reefs and are responsible for their bleaching.
Offshore corals in France, Guadeloupe, Martinique, Réunion and Mayotte are also affected. The National Agency for Health Security (ANSES) noted after reviewing the available scientific literature on the subject with the support of the French Biodiversity Office. toxicity to corals of three UV filters available in sunscreens. These are oxybenzone, octinoxate and octocryl.
How to identify sunscreens that respect the marine environment? ANSES services warn against the presence of pictograms or expressions on some sunscreens that emphasize the supposed respect for the marine environment:
In practice, therefore, the solution is to go through the ingredients list to check that a sunscreen does not contain one of these three UV filters.
What are the health risks of mineral filters in the form of nanoparticles?
Sunscreens raise questions about our health, especially due to the presence of nanoparticles (titanium dioxide, zinc oxide).
Nanoparticles are very small particles less than 100 nm in size (ie 10,000 times smaller than a raspberry seed). Their use in sunscreen improves product absorption and reduces the “white color” effect on the skin. In short, many offer the comfort and aesthetics sought, if not demanded, by consumers who shy away from applying “white paste.”
The problem with these nanoparticles is their ability to cross biological membranes. Today, science does not know much about their effects on our health. However, various studies agree that using sunscreens containing titanium dioxide is safe for healthy skin, but not. on damaged skin or in people suffering from skin disease.
Anti-UV clothing to protect yourself from the sun
So is the dress an alternative? Be careful, just any summer outfit won’t do the trick… An ordinary white shirt made of light cotton allows 20% of UV rays to pass through. This may provide a sense of protection, but burnout can happen more or less quickly according to photo type of the person.
In addition, its effectiveness decreases even more when it gets wet. On the other hand, there are anti-UV clothes specially designed to protect against the sun’s UV rays.
The anti-UV properties of clothing mainly depend on:
- its color (UV rays are best blocked by bright or dark colors)
- textile fabric (cotton with an airy texture is less protective than polyester with a tighter weave) and
- Addition of additives that reduce the penetration of UV rays (for example, ceramic particles).
The best UV protection: combine suitable textiles and sunscreen
As with sunscreen, the UV protection effectiveness of this garment is determined by the UPF (ultraviolet protection factor) rating, which measures the proportion of UV rays blocked.
When anti-UV clothes appear 50+ FPU, which means they block over 98% of UV rays (as much as a SPF 50 sunscreen). You should still remember to renew your anti-UV clothing regularly (preferably every new season), as their effectiveness can decrease with wear or stretching.
On the other hand, even when wearing clothes with a high UPF, not all parts of the body are protected, this is especially the case for the face. Therefore, it is recommended to protect them suitable sunscreen. Additionally, wearing a wide-brimmed hat and sunglasses is strongly recommended.
Finally, to effectively protect yourself from the sun, nothing beats … a little shade.