Ultraviolet Radiation

So it’s summer, the days are warm, and you want to have some fun in the sun! You are recommended, however, to limit the time you spend outside because of something called ‘ultraviolet radiation’. But what is ultraviolet radiation and why should we be concerned about it?

Ultraviolet Radiation

Ultraviolet (UV) radiation is one of the many forms of energy that exist, and it is emitted by the sun. It has shorter wavelengths than visible light, which allows it to appear invisible. Here’s a correlation you’re going to want to remember: the shorter the wavelength, the more energy the rays have.

There are three subtypes of UV radiation:


This form of radiation has the longest wavelength of the three, and it isn’t absorbed by the ozone layer at all. Therefore, 100% of these waves reach the Earth’s surface. This form of UV radiation is the least lethal of the three (longest wavelength, least energy).


This form of radiation has a wavelength that is between UVA and UVA. For the most part, these waves of energy are absorbed by the ozone layer; however, some of these rays are able to reach the Earth’s surface. This form of UV radiation is the one that everyone is worried about as it can be very harmful.


This of form of UV radiation has the shortest wavelength, and is therefore extremely lethal (shortest wavelength, most energy). Luckily, the ozone layer absorbs all of these rays, allowing us to be protected from them.


So, we know now that UVA and UVB rays reach us when we’re out in the sun. The perks of this is that UV radiation can provide us with Vitamin D, which can help strengthen our bones and teeth. These rays also help treat psoriasis and eczema, skin diseases where itchy patches form, by slowing the growth of skin cells! Also, a lot of people like tanning which can be attributed to exposure to UV radiation.


UV radiation can be worrying too because it can cause a variety of things including sunburns, skin cancer, and even cataracts. The amount of exposure to these rays determine how detrimental the result is.

Protect Yourself

In order to lessen the effects that UV radiation can have on you when you’re out and about, it’s suggested that you wear long, loose clothing. But, let’s be real here, that’s not going to happen when the temperature is around 20°C/68°F or higher. So your best bet is to stay in the shade when you can, and to pull out your sunscreen lotion and slather it on.

The lotion will have a particular Sun Protection Factor (SPF) associated with it. This number is indicative of how long you can be in the sun before you get a sunburn. Let me explain: if the SPF of the lotion is 30, then it will take you 30x longer than usual to get a sunburn. What does that mean? Well, if you normally get a sunburn after being in the sun for 15 minutes, then it will take you 450 minutes to get a sunburn if you use a lotion with an SPF of 30. It’s recommended that you use lotions with an SPF of at least 15. But if you know how long it takes you to burn and you know how long you’re going to be out in the sun, then some simple math could save you some pain.

And there you have it, UV radiation. Your skin is welcome. 

Upcoming posts: Sunburns and Tanning, oh my!



Eipstein, J.H., and Wang, S.Q. 2013. Understanding UVA and UVB. skincancer.org. <http://www.skincancer.org/prevention/uva-and-uvb/understanding-uva-and-uvb> July 18, 2013.

Estes, P. 2013. What are UV rays? WiseGeek.com. <http://www.wisegeek.com/what-are-uv-rays.htm> July 18, 2013.

World Health Organization. 2013. Health effects of UV radiation. WHO.int. <http://www.who.int/uv/health/en/> July 18, 2013.


4 thoughts on “Ultraviolet Radiation

  1. Pingback: Sunburns | Know Your Body and Health

  2. Pingback: Tanning | Know Your Body and Health

  3. Pingback: On a related note… | Know Your Body and Health

  4. Pingback: Melanin | Know Your Body and Health

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