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[Living Green] Safety Column #7 Danger in the warm sunlight

by Eco Generation | 10-07-2020 08:40 Comments 4 recommendations 1

Danger in the warm sunlight



By Science Columnist Ho-Gwan Ko



To live a healthy life, having proper outdoor activities is important. This is especially true for teenagers while growing up. Playing outside, you can vitalize your body and mind. In fact, people who live in areas with less sun exposure suffer from depression in winter. It is also true that sunshine on a nice day makes you feel good.

However, sunlight is not always good, because it also contains harmful ultraviolet (UV) rays. UV light has a shorter wavelength than visible light. Visible light is known as light with rainbow colors. UV light is outside the violet region. On the other hand, infrared light is outside the red region.

UV rays are so strong that they harm our bodies. To be specific, they are harmful to the skin and eyes. If your bare skin is exposed to sunlight for a long time, you may get burned and the skin peels off, which is due to UV rays. This can cause skin aging and even cancer. Strong UV light damages DNA, induces mutations, and creates cancer cells.

There are three different types of UV radiation: UVA, which has the longest wavelength, UVC, with the shortest wavelength, and UVB in between them. UVA penetrates the deeper layers of skin, causing aging. It causes the skin to become darker; the skin turns darker while producing melanin to protect against UVA.

UVB does not penetrate deep into the skin but causes burns on the outer layer of skin. If your skin was exposed to sunlight and had a red burn, that is because of UVB. UVC has the strongest energy and is the most harmful to the human body. It causes cancer.

Since each UV type has different characteristics, we take slightly different actions to block them. Fortunately, most UVC radiation is blocked by the ozone layer. This is why the ozone layer is important. If the layer is destroyed and UVC reaches the ground, it can be very dangerous to be exposed to sunlight. The layer blocks more than 90 percent of UVB, but it hardly blocks UVA.

Therefore, only UVA and some UVB that have passed through the ozone layer reach the ground. UVB does not pass through windows. However, UVA penetrates window glass, making the skin become darker even when you are indoors.

If you need to stay in the sun for a long time, you should use sunscreen. However, UVA and UVB are blocked by different methods. For UVA, we use “inorganic sunscreens.” They reflect UV rays by applying titanium dioxide or zinc oxide powder on the skin. It physically blocks UV rays from reaching the skin. For UVB, we use “organic sunscreens.” Various organic compounds absorb UV rays and convert them into heat.


Danger in the warm sunlight

▲ To avoid any damage from UV, wear sunscreen well before outdoor activities.

Most sunscreens contain both UVA and UVB protection. However, the ratio is slightly different, so it is good to choose a sunscreen suitable for your purpose. The PA rating and SPF index on a product packaging indicate which and how many UV rays are blocked. The PA rating indicates the ability to block UVA. The more +, the better the performance.

The SPF index indicates the ability to block UVB and usually comes in SPF 15, 30, and 50. The numbers tell you how many times more sunlight you can be exposed to without getting burned when you apply it. Multiply the SPF by 10-15 minutes to know how many minutes you can protect your skin. For example, if your SPF is 50, you can block UV rays for 500-750 minutes.

If you are indoors and in the sun, you can choose your sunscreen by the PA rating. If you want to tan your skin without getting a red burn at the beach in summer, you can choose a product with a low PA rating and a high SPF index. However, you need to reapply sunscreen frequently, if you are swimming or sweating outdoors, because the effect gradually decreases.


* Let’s learn the effects of sunscreen!

UV rays cause chemical reactions that fade the colors of pictures or prints. You may have noticed that paintings exposed to sunlight for a long time fade. Based on this, let's see the effect of sunscreen.

Prepare a piece of black drawing paper and write or draw on it with sunscreen. Use a generous amount. Then leave the paper in a well-lit place for about a week. See how the colors of the areas where sunscreen was applied and not applied have changed.


Yasmin Hussain

  • Yasmin Hussain says :
    I do use sunscreen but never knew that different sunscreen for different types of UV. I'm just using the sunscreen based on the SPF but not the ingredients. This is a good article to read Thank You in advance :)
    Posted 04-11-2020 12:04

Houra Yousefi

  • Houra Yousefi says :
    I am actually shocked since I usually would get tan in the sun without knowing these things would happen to me.
    thank you so much for the information.
    I will also try that experiment soon!
    Posted 25-07-2020 12:43

NsikakAbasi Etim Jnr

Kushal Naharki

  • Kushal Naharki says :
    Sunlight is considered good for our health, as we receive vitamin d for us . Thanks for letting us the harmful effects that it can have.
    this series of articles is so amazing. Thank you EcoGeneration for bringing such amazing articles every week.
    Posted 17-07-2020 16:21

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