Growing up I suffered from being fair skinned.
However much I wanted to sport a health glow just like my friends did, the only thing I was able to get were pretty bad sunburns. Here just one of my memorable burns: I was 10 years old and desperately wanted to try windsurfing while vacationing with my mom in Terracina,Italy. We only had an adult sized rig and no means for a child sized one. So my lucky day was when friends offered me to try theirs the following day. At the end of a sun-filled day, being back from the beach, the whole backside of my body was fire! And red like a lobster! The only thing left for me was staying in bed with my backside being smothered with yoghurt and honey for three days. Not quite sure what hurt more: The fact that I couldn’t walk because the skin in the back of my knees was so tender, or because I lost the once of a lifetime chance of being on a me-sized surfboard?
I am sure everybody has one or more stories just like this and everybody knows that exposure to the sun causes sunburn and skin aging, but few really know details and all the rating is quite confusing. UVA, UVB, SPF30, UPF30? What the heck does all this exactly mean?
Ultraviolet Rays
There are three types of UV (ultraviolet) rays emitted from the sun: UVA, UVB and UVC which all have different wavelengths which are shorter than visible wave lengths (colors) and therefore can’t be seen with the naked eye.
While UVC rays are absorbed by the ozone layer before even reaching the earth, it’s the UVA and UVB rays that play a role in premature skin aging, reddening of the skin and development of skin cancer.
UVA accounts for 95% of the UV radiation on the earth. While UVA rays are less intense then UVB (and were once believed to be less harmful also) they are equally prevalent during daylight times throughout the year. UVA rays cause skin aging and wrinkling and are the dominant tanning ray which penetrate the deeper layers of the epidermis and is found to cause damage in the basal layer of the Epidermis – which is exactly where most skin cancers occur.
Another side effect of UVA exposure is the sense of sleepyness. Have you ever wondered how on earth can you still be tired after a full day of laying lazy at the beach? Even though you were hanging out in the shade?
UVB rays are the ones that cause those nasty burns. UVB rays are responsible for skin reddening and damage to the superficial epidermal layer and play a major cause in developing skin cancer. The intensity of UVB exposure depends on the season and time of day. The highest UVB exposure is from 10am to 4pm in the US, April to October. Basically when the sun is highest – the UVB exposure is too.
UVB exposure however is not limited to spring and summer time. It can can be high year round – and especially threatening for athletes! High altitude and reflective surfaces will bounce back up to 80% of the rays, resulting in a double whammy as the rays are hitting the skin twice – and from all angles!
How to protect ourselves?
Besides seeking shade outdoors between 10am and 4pm and the use of tinted windows which blocks out 99% of the UVA rays, there are generally two types of protection you can buy in store: UPF and SPF
UPF (Ultraviolet Protection Factor) is used to rate clothing. (more on that next week!)
SPF (Sun Protection Factor) is used to rate Suncreams.
Even though UPF and SPF factors both get numerical rating, the meaning of those numbers is quite different and shouldn’t be confused!
A UPF of 30 means that only 30% of the sun’s rays can penetrate the fabric.
The SPF rating doesn’t indicate the amount of sun protection. The factor is highly personal: It indicates how long it’ll take for your skin to redden with sunscreen in comparison to how long it would take without a product. So an SPF of 30 gives you 30 times longer to stay outdoors before you get a sunburn.
source: wikipedia
The Skin Cancer Foundation recommends an SPF of at least 15 for adequate protection, but here is how the protection breaks down:
SPF 15 filters 93% of UVB rays
SPF 30 filters 97% of UVB rays
SPF 50 filters 99% of UVB rays
If you haven’t only skimmed this article so far, you are wondering – wait a minute! Looks like only UVB rays are filtered in modern sun screen. What about the equally harmful UVA rays?
To date, manufacturers aren’t required to measure and label UVA protection on sun screen product. There are multi spectrum sun screen products available that filter some of the UVA rays but as there is no requirement about how much UVA rays have to be filtered out. So, be careful.
There are two types of FDA approved filtering agents in suncreams: organic (chemical) and inorganic (physical) filters. (Why the heck are the chemical substances called organic???)
The most common filters are the chemical ones which form a thin protective film on the skin and absorb the UV rays before they penetrate the skin. Check what’s approved by the FDA: Avobenzone, Ecamsule (a.k.a. Mexoryl™), Oxybenzone. Also, click on the links above and you’ll find generally concerning data on filtering agents Avobenzone and Oxybenzone that can in turn cause cancer, allergies and hormone disruption and cell damage. Isnt’ it interesting how one evil is fought with another set of evil?
The inorganic/physical filter are: Zinc Oxide and Titanium Dioxide. Those inorganic/qhysical filters are insoluble particles that reflect the rays away from the skin (and are not absorbed).
Looking at above chart, the one and only agent that filters UVA and UVB at extensive levels is Zinc Oxide.
According to Soapwire:
1. Zinc Oxide has a broader UVA spectral absorbance than Titanium Dioxide
2. Zinc Oxide is safer from oxidative free radical production and chemical damage
3. Zinc Oxide is not made from a toxic heavy metal
4. Zinc Oxide is the ONLY sunscreen that is FDA-approved for use on babies younger than 6 months of age. (This is despite the fact that many mass market manufacturers market ‘baby’ formulas full of petrochemicals that are NOT approved for use on babies!)
The last fact illustrates that Zinc Oxide is the also the safest sunscreen on the market and the only one you should be using on your children.
Here is what we use:
It’s by Goddess Garden and now sold at New Seasons. For a list of mineral based sunscreens at Green Guide with pricing comparison, click here.
To conclude:
- UVA and UVB rays are equally responsible for sun damage.
- SPF of 15 is the minimum Sun Protection Factor you should use.
- Be safe and choose a sun screen that uses Zinc Oxide as filtering agent as it has the best protection against both, UVA and UVB rays.
- UPF (UV Protection Rating) ratings are used for garments.
Because this weeks Tuesday Tech Talk turned out to be quite lengthy, I’ll break it up into two parts, with the second part about UPF rating, fiber, fabric, washing and color info being published next week which will be even more informational especial for designers.
Sources: Illustrations and Tables: Skincancer Foundationhttp://www.skincancer.org http://www.soap-wire.com/2008/09/mineral-sunscre.html
http://www.vivawoman.net/2008/09/26/mineral-based-sunscreens-are-the-best/
http://www.thegreenguide.com/buying-guide/sunscreen/smart_shoppers_list
http://en.wikipedia.org/wiki/Sunscreen
