There are 2 types of UV’s, and they’re not the same
UV-A and UV-B (it is considered that UV-C rays are too short to have any impact, although the thinning of the ozone layer might tell us a different story overtime). UV-B are the main cause of sunburns if you get too much of them, but also the ones that help our body synthesize vitamin D, if you just get reasonable exposure with non protected skin (arms and legs, the face should always be protected). Skinergies mobile app Sun Keeper helps you with the amount of time you need, depending on your skin type, your location and the time of year it is.
We know UV-B because they warm our skin and get us red when we get too much of them. But there’s UV-A. And they’re a totally different story.
While both UV-A and UV-B radiation can cause melanoma, UVA is the most dangerous
When UV-B are seasonal and vary in intensity (with pretty much no intensity between October-April in the Northern part of the US, and an intensity so low that no protection is required in the rest of the country), UV-A are year-round, about 100 more intense than UV-B, and they easily penetrate window glass and clouds. On top of everything, because they penetrate deeper in our skin than UV-B, they are the #1 cause of irreversible damage to our skin, starting with photoaging and worse, melanoma.
In situations of daily exposure to UV through daylight (you know, when you run an errand or go get lunch around the block), the damage caused by UV-B is very little compared to UV-A: the skin has the ability to repair automatically and naturally within 30 minutes and restore the damage caused on the DNA by UV-B. on the other hand, UVA generate free radical production, causing some serious cell oxidative damage and degradation on the DNA structure, leading to mutations that can cause melanoma on the long run.
UV-A is following you everywhere, even inside your building
Scientists in Central Europe have decided to measure the amount of UV radiation (UV-A and B) that penetrates window glass. For this experiment, people were equipped with small UV dosimeters; exposure was measured on typical working days, during sunny summer. When less than 8% of outside UV-B radiation was measured indoors (a harmless dose), about 40% of the outdoor UV-A radiation dose could still be received indoors.
This study shows that of real relevance for daily skincare are therefore not SPF factors (that address UV-B) but UV-A protection. And this applies to every skin tone, whether fair or dark.
You need protection year-round, wherever you’re located in the US
To give you an idea of how much your exposure to UV radiation can vary, the graph below shows the average monthly UV Index levels for New York and Los Angeles from 2017. The UV Index is the net level of UV radiation reaching an area, accounting for mitigating factors such as location, elevation, and cloud cover. The UV Index is used by the US Environmental Protection Agency and the National Weather Service to help people figure out how to prepare themselves for sun exposure every day—just like you prepare yourself for the daily weather! The low end of the index represents relatively low levels of risk of overexposure, and the risk increases as you move up the scale.
So now with the fall coming and with it, more acceptable temperatures, it’s not the time to leave your skin unprotected from UV. Your body is gradually going to be more covered due to the falling temperature but think about your face (and scalp): these parts of the body are the least protected (the SPF you apply in the morning is long gone by the time you get to the office, and it’s for UV-B, not UV-A anyway), and where damage happens the most.
This is what we’re working on at Skinergies: our mission is to develop skin care products that are able to deliver efficient daylight protection without harming the body or the environment. Our filters are natural, not synthetic like in traditional sun protection products. Because we believe that cosmetic products intended for everyday use should be absolutely safe.
Read more about our UV-A filters