UVB rays damage the outermost layers of the skin. They directly damage DNA. UVB rays cause most skin cancers, but they can also contribute to skin aging prematurely.

The most common form of UV radiation is sunlight, which produces three main types of UV rays:

• UVA.
• UVB.
• UVC.

Solar UVR of wavelengths shorter than 290 nm are filtered out or absorbed in the outer atmosphere and are not encountered at sea level. Shorter wavelength UVB rays are much more effective at inducing erythema than UVA rays and, therefore, are the principal cause of sunburn.

They can damage the DNA in skin cells directly, and are the main rays that cause sunburns. They are also thought to cause most skin cancers. UVC rays have more energy than the other types of UV rays.

On the one hand, UVC is the most dangerous because it’s the highest energy portion on the UV spectrum. It accounts for nearly all UV exposure as it’s barely blocked by the earth’s atmosphere. That said, it’s also the shortest wavelength and isn’t thought to cause as much long-term damage as UVB from the sun.

No measurable UVC from the sun reaches the earth’s surface. Because of the spectral sensitivity of DNA, only the UVC region demonstrates significant germicidal properties.

ultraviolet C

Ultraviolet energy should first and foremost be identified by its wavelength. UV-A encompasses wavelengths between 315 and 400 nanometers, while UV-C includes wavelengths from 100 and 280 nanometers. UV-B wavelengths fall in between at 280 and 315 nanometers.

UV radiation is widely used in industrial processes and in medical and dental practices for a variety of purposes, such as killing bacteria, creating fluorescent effects, curing inks and resins, phototherapy and suntanning. Different UV wavelengths and intensities are used for different purposes.

aThe human eye can see light with wavelengths between 380 and 700 nanometers. cMost humans cannot see ultraviolet light because it has a shorter wavelength than violet light, putting it outside of the visible spectrum.

Ultraviolet light is a form of radiation which is not visible to the human eye. It’s in an invisible part of the “electromagnetic spectrum”. Radiated energy, or radiation, is given off by many objects: a light bulb, a crackling fire, and stars are some examples of objects which emit radiation.

The UV region covers the wavelength range 100-400 nm and is divided into three bands: UVA (315-400 nm) UVB (280-315 nm) UVC (100-280 nm).

UVB rays, which affect skin’s top layer, cause skin cancer and most sunburns. Although UVA and UVB rays pose the greatest risk for sun damage, people who work with welding torches or mercury lamps may be exposed to UVC rays, the most dangerous type of UV radiation.

UV-B light (290-320nm) causes sunburns with prolonged exposure along with increasing the risk of skin cancer and other cellular damage. About 95% of all UV-B light is absorbed by the ozone in Earth’s atmosphere. UV-C light (100-290nm) is extremely harmful and is almost completely absorbed by Earth’s atmosphere.

A high UV Index reading means there is high risk of harm from unprotected sun exposure. A UV Index reading of 11 or more means extreme risk of harm from unprotected sun exposure. Take all precautions because unprotected skin and eyes can burn in minutes.

A UV Index reading of 11 or more means extreme risk of harm from unprotected sun exposure. If outdoors, seek shade and wear protective clothing, a wide-brimmed hat, and UV-blocking sunglasses.

6-7

New Zealand

5,920 meters

two hours

A computer model uses the ozone forecast and the incident angle of sunlight at each point to calculate the strength of UV radiation at ground level. Sunlight angle is determined by latitude, day of year, and time of day (solar noon).

Whether the UV Index is 1 or 5, you should always wear a broad spectrum sunscreen of at least SPF 30. When the UV Index number is high (aka above 6), it would be best to layer your sunscreen––but again, we’re big fans of doing this on a daily basis, regardless of what the UV Index is.

So how do you decide what is a good UV index for tanning? *This is a general recommendation and varies depending on your location, altitude, and skin tone. Moderate includes UV index ranges from an index of 3 to 5, vs. high which is 6-7, very high which is 8-10 and extreme which is 11+.

The UV Index was previously reported on a scale of 0 to 10+, with 0 representing “Minimal” and 10+ representing “Very High.” As of May 2004, EPA and NWS will report the Global Solar UV Index using a scale of 1 (or “Low”) to 11 and higher (or “Extreme”).

The time to burn can vary by skin type, but at a moderate UV level it is approximately 30 to 45 minutes. A UV Index reading 6 or 7 puts you at a high risk of harm from unprotected sun exposure.

A UV Index reading two or lower means there is a minimal risk of sunburn for the average person. At this level it is suggested to wear sunglasses, use broad spectrum sunscreen and watch out for bright surfaces like sand, water and snow which reflect UV rays, increasing your exposure.

Yes, tanning through clouds is possible. It does not matter how cloudy, hazy, or even rainy the day is there is still a chance of getting a tan, and even worse, a burn. Thick grey or black clouds will absorb some of the rays and not allow as much UV light through, but some will still get through and into your skin.

Applying self-tanner will give you a dark tan in one day, but it is not permanent. You will have to reapply the self-tanner in a week or so, but it is still the best option to self-tan at home without any damage done to your skin.

How to get a tan faster

1. Use sunscreen with an SPF of 30.
2. Change positions frequently.
3. Eat foods that contain beta carotene.
4. Try using oils with naturally occurring SPF.
5. Don’t stay outside for longer than your skin can create melanin.
6. Eat lycopene-rich foods.
7. Choose your tanning time wisely.