With summer nearly upon us - the days get longer, the weather gets warmer, we keep our beverages cooler, and most importantly, we spend more time enjoying the outdoors. And like most things in life – too much of a good thing can become detrimental. So, when it comes to summertime and enjoying the sun - it never hurts to take the extra precaution in keeping your skin and body safe. As the proverbial saying goes, “Health is wealth.”
Applying sunscreen isn’t always the most enjoyable of tasks – lathering on an interesting smelling substance that leaves your skin feeling slightly sticky really doesn’t sound all that appealing. With this in mind, it’s reasonable why a person would look for other ways to protect themselves from the sun. Unfortunately, though it seems logical that staying in the shade when outside would be an appropriate countermeasure against the sun’s harmful rays – this could not be further from the truth. Remember – like it or not, sunscreen is your friend.
Yes, Sun Umbrellas Protect From UV But…
Using a sun umbrella or other types of physical barriers to create shade intuitively seems like an effective way to protect ourselves from the sun. By creating a blockade against the sun’s rays, shaded areas are cooler and provide a sense of relief from being impaled by the sun’s harsh light. However, this sense of security can mislead individuals into thinking they no longer need sunscreen or have to reapply it as long as they stay in the shade.
Taking an umbrella to the beach is a common practice among outdoor aficionados, yet it is not very well known that even in shaded areas a person is still exposed to UV radiation.[1-4] Though a beach umbrella reduces the amount of UV radiation that directly reaches our skin, it has almost no effects on reducing scattered/ indirect UV rays that have bounced off of other objects before getting to the skin.[1-4] So even when using beach umbrellas for sun protection, one is still being bombarded with UV radiation from the sun even though they may not sense it.
No, Sun Umbrellas Do Not Stop Diffuse UV Radiation
Solar UV radiation can be broken down into three components – beam radiation, reflected radiation, and diffuse radiation.
Beam radiation can be defined as the solar rays that have a defined direction – meaning that all the rays from the sun strike the Earth’s surface at the same angle. When we utilize physical barriers such as umbrellas, we usually direct the umbrella towards the direction of the sun - thus gaining some protection from the beam component of the sun’s radiation.
Reflected radiation is essentially what it sounds like. UV radiation that makes contact with the ground can be reflected back upwards and penetrate our skin. So even when in the shade, UV radiation reflected from the ground could still be causing sun damage.
The amount of radiation reflected back upwards depends on the type of surface. With snow and sand having greater reflectivity, whereas surfaces such as grass and concrete reflect UV radiation significantly less.[4,5]
Diffuse radiation, on the other hand, is the solar rays that have no definitive direction. As solar rays make their journey through the Earth’s atmosphere they have the potential to interact with molecules in the air and with water – thus becoming scattered or diffuse.[1-5] Because diffuse radiation does not have a single source (like the sun in beam radiation) individuals in the comfort of the shade may still be bombarded with ultraviolet radiation from many different angles.[1-5]
In a study conducted measuring diffuse radiation in direct sunlight vs in the shade – researchers noted some surprising results. Measuring both total UV and ultraviolet type A (UVA) radiation, it was seen that at noon in direct sunlight that 26% of the UV radiation measured was from the diffuse component and 20% of the UVA radiation measured was from the diffuse component. Whereas at noon, under the cover of shade - 60% of the UV radiation measured was from the diffuse component and 57% of the UVA radiation measured was from the diffuse component. These dramatic numbers reiterate that in even in the shade, we are subject to UV radiation whether we sense it or not.
Table 1. Percentage of Incident Radiation Reflected by Different Surfaces[4,7]
% of UV Radiation Reflected
No, UV Radiation Is Everywhere and Sun Umbrellas are Not Enough
Excessive UV radiation exposure is known to have multiple negative effects on human health, from sunburn, photoaging, and eye damage to DNA mutations and skin cancer. This is not to say that UV radiation is inherently bad for us – UV exposure in small quantities is known to have health benefits. But when spending the day outside, it is imperative that we are diligent and take extra measures to protect our skin.
Studies have shown that staying in the shade provided by beach umbrellas can still lead to sunburns and may not be as effective as using high SPF sunscreen. Not to say that using sunscreen grants all-encompassing protection from the sun, because it does not. Instead, sunscreen should be used along with staying in the shade. Using two forms of skin protection (sunscreen & an umbrella) provides better UV skin protection and reduces skin sun damage more so than just using either protective measure by itself. Because umbrellas provide limited protection against scattered and reflected UV radiation and because excessive sun exposure can still cause sunburn even when wearing sunscreen, it is recommended to both use sunscreen and stay in the shade when spending the day outside.
So the next time you plan a beach day, remember that best way to keep your skin healthy is to bring an umbrella and wear a lot of sunscreen.
* This Website is for general skin beauty, wellness, and health information only. This Website is not to be used as a substitute for medical advice, diagnosis or treatment of any health condition or problem. The information provided on this Website should never be used to disregard, delay, or refuse treatment or advice from a physician or a qualified health provider.
Kudish AI, Harari M, Evseev EG. The solar ultraviolet B radiation protection provided by shading devices with regard to its diffuse component. Photodermatology, photoimmunology & photomedicine.2011;27(5):236-244; PMID: Link To Research.
Ou-Yang H, Jiang LI, Meyer K, et al. Sun Protection by Beach Umbrella vs Sunscreen With a High Sun Protection Factor: A Randomized Clinical Trial. JAMA dermatology.2017;153(3):304-308; PMID: Link To Research.
Ou-Yang H, Shyr T. Sun protection by umbrellas and walls. Photochemical & photobiological sciences : Official journal of the European Photochemistry Association and the European Society for Photobiology.2017;16(10):1537-1545; PMID: Link To Research.
Utrillas MP, Martínez-Lozano JA, Nuñez M. Ultraviolet radiation protection by a beach umbrella. Photochemistry and photobiology.2010;86(2):449-456; PMID: Link To Research.
Vernez D, Milon A, Vuilleumier L, et al. Anatomical exposure patterns of skin to sunlight: relative contributions of direct, diffuse and reflected ultraviolet radiation. British Journal of Dermatology.2012;167(2):383-390; PMID: Link To Research.
Parisi AV, Kimlin MG, Wong JC, et al. Diffuse component of solar ultraviolet radiation in tree shade. Journal of photochemistry and photobiology. B, Biology.2000;54(2-3):116-120; PMID: Link To Research.
Opene C, Chren M-M, Linos E. Types of Shade Vary in Protection Just Like. JAMA dermatology.2018;153(10):1070-1071; PMID: Link To Research.