The Sunscreen Smokescreen

Monday, July 11th, 2011

It started with a question. It always does. This time, the question was simple: How much sunscreen should I wear?

I’m a pale geek who burns. I wanted to know the optimal. A simple question with a simple answer, right?

Wrong.

This simple question took me on a massive journey through the data, information myths and misinformation that surround our perception of sunscreen. I’m calling it the Sunscreen Smokescreen.

All our data, calculations and references here: http://www.bit.ly/sunscreensmoke

The Sunscreen SmokeScreen - Information Is Beautiful - David McCandless

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Show Comments ( )

  • http://www.shinyphoto.co.uk/ Tim

    Careful. The `Melanoma Mysteries’ graphs have very different ordinate scales; from the lines it looks like people in the UK are about twice as susceptible as the US, and have practiced less safety of late; if you normalise the scales then that’s nothing *like* the case. Sorry, but that’s an omission veering on deception, not in the spirit I associate with InformationIsBeautiful at all.

    • John

      The header above that graph says that Melanoma rates are increasing, I think that’s all they’re trying to show. Though maybe they could just put all three on one graph with a common scale. I wouldn’t say that it’s being deceptive.

    • iamjoebob

      The Brits experience about 2 or 3 extra hours of sunlight on an average Summer day than the US, and (generally) are more fair skinned. I wonder if there’s some connection?

  • http://youmustbefromaway.wordpress.com/ John B

    “An omission veering on deception”?
    I wouldn’t go as far as that, but it’s sloppy stuff and you need to fix it, otherwise it’s just eye candy.
    And a bit overloaded, maybe

    • david

      hmmm. dunno about “deception”. the axes were clearly labelled. “confusing” though, I’ll accept ;) I’ve amended the diagram. Plus I’ve removed a bit of info. It is a bit overloaded.

      • http://www.gollyjer.com Jeremy Gollehon

        Now there’s two “cases per hundred thousand people” labels. :-)

      • http://www.shinyphoto.co.uk/ Tim

        Thanks. Yup, that’s *much* better.

        Interesting how AUS is so much more volatile.

        • Jessica

          We’re more susceptible to sun-related cancers due to the thinning of the ozone layer – the hole is much closer to us than it is to the rest of the populated world, and we have much less “natural sunscreen” in our atmosphere.

          So it’s interesting, but not really surprising, unfortunately :(

        • Shane

          Australia is more susceptible to skin cancer due to a population largely made up of fair skinned European descendants, an outdoor lifestyle and a whopping great ozone hole sitting over a lot of it.

  • gabitbol

    Tim, I think the author wanted to show the evolution of melanoma cancers, regardless of the absolute figures. But you are right that it can give false ideas, which is quite the opposite of the aim of InfomationIsBeautiful.

  • Ciaran

    Countries where more sunscreen is used are likely to be more sunny than ones where little sunscreen is used, this doesn’t seem too surprising to me. Tim’s dead right about the graphs, the different axes are unclear and confusing.

  • Andy

    The altitude graph could do with a height scale to be meaningful, otherwise the 10-20% increases are pointless.

    Excellent graphic otherwise, never realised how much suncream was need to even hit the ‘recommended’ amount.

    • Duncan

      What’s up with Oz? Those are very high melanoma numbers.

      • http://slight-hiccup.com Jen

        It’s quite sunny there… It is, after all, a “sunburnt country” and the country of “slip, slop, slap”, “no hate, no play” and public service ads about the “dark side of tanning”.

        • Mic Edwards

          Fortunately, it’s “no hat, no play” … although some Australian politicians have certainly stoked the fire of hatred over the years …

  • http://www.gollyjer.com Jeremy Gollehon

    The ‘Melanoma Mysteries’ charts serve their purpose to show the trend in each country perfectly fine. They aren’t meant to compare the difference in total cases per country.

  • Greemble

    “An omission veering on deception”

    I rather agree with Tim on this – The UK & US graphs could have used the same scale. It’s obviously not intentional, no adverts here for sunscreen that I can see, but it is so sloppy that veering that way has got to be said – Especially as the time axis has been matched in for all three.
    How about merging all three onto one graph?

    I’d be very interested to see the sales of sunscreen for the same period in the same countries as well

  • Chiara

    Sunscreen and SPF still make no sense to me… I’ve heard many times that every unit of SPF gives you 15 minutes of sun-protection… So reapplying SPF 2 every half hour is the same as applying SPF 60 once? That can’t be right! Or if it is, then SPF 60 is just a dumb marketing gimmick since there aren’t even 15 hours of sunlight in a day.

    • molars

      No, SPF is basically the denominator of the fraction of UVB light blocked by the sunscreen. 15minutes is just an estimation of how long an average person’s skin can be exposed to UVB before tanning or damaging effects occur.

      Each application of sunscreen does not guarantee the amount of time it protects you, you will still need to reapply once it wears off.

      So for example, if you want to avoid sunburn for 6 hours on the beach and you usually get sunburn after 2 hours without sunscreen. Not taking other factors into account, you will need to apply sunscreen with an SPF of 3. Even then, you will still have to reapply after a certain interval to restore the worn off sunscreen.

      Also, some people have very sensitive skin or skin conditions that require an abnormally high SPF. Remember that the 15minute is just a general estimate.

      • http://www.christopherdgray.co.uk Chris

        molars: I agree – it should be stressed that the 15 minute figure is just a general estimate and varies greatly by person. Unfortunately the most accurate estimate of timings comes when you know how long your skin takes to burn, which defeats the purpose!

  • http://www.medicallessons.net Elaine Schattner, MD

    I’m a fan of this blog and appreciate many of your images. But this graphic is way, way too complicated.

    • david

      any ideas how I might simplify / optimise?

      • SarahX

        I’d show the following:

        SUN + SKIN = SKIN CANCER

        SUN + SKIN + UVA SUNBLOCK = SKIN CANCER (but you’ll look younger)

        SUN + SKIN + UVA/UVB SUNBLOCK (no skimping) = PROTECTION

        Unfortunately…
        SUN + YOU = BETTER HEALTH
        SUNSCREEN CHEMICALS + YOU = CANCER (we think)

        What to do???
        As a survivor of 15 plus skin cancers (and oh-so-many more biopsies), my dermatologist and I have come up with this plan:

        Wear a hat, UPF clothing, and sit in the shade.

        • Stef

          UVA radiation is more likely cause cancer (not just “aging”).
          (Just an FYI) SPF refers only to UVB protection. Everyone should be wearing a sunscreen that protects against both (as determined by the ingredients).

  • http://www.oursacredroots.com Mary

    It’s possible that using sunscreen causes melanomas. Vitamin D is an essential nutrient that most people are lacking. It helps prevent osteoporosis, autoimmune diseases and cancer. I don’t think a general ’20 minute’ exposure recommendation is appropriate for everyone. Our bodies vary in their ability to absorb it from the sun and the amount we receive depends on our location and time of year. Also, it makes no sense to apply heavy toxins to our skin which is the largest organ on our bodies and expect it to protect us from cancer. I image the chemicals wreck havoc in our bodies and lower our defense against cancer. I’m sure all the past generations of humans didn’t wear sunscreen and they survived just fine. Plus they spent more time outdoors. Perhaps this is why melanomas are more likely to appear in areas not exposed to the sun.

    • in the sun

      Past generations could get away with not using sunscreen because they didn’t live for 80 years.

      Our bodies were made to last 35 to 40 years. We need some non-natural help to use our bodies for twice the intended lifespan.

      Eventually evolution will catch up, but that’s gonna take a while. Evolution does its job thousands of years after the fact.

    • Stef

      The molecules in sunscreens are too large to pass through the skin barrier. It has been theorized that some of the newer micronized formulations *may* have molecules small enough to pass through. If you wish to protect yourself from formulations that *may* pass through, use formulations that leave the white film. These are more likely to contain physical UV blockers and operate by physically blocking the UV rays (hence the whitish appearance). Titanium Dioxide is a good UVB blocker and Zinc Oxide is a good UVA blocker – they both are physical blockers that in their non-micronized form simply stay on the surface of the skin.

  • K-eM

    What is the altitude the burn time is based on?

    As someone who is extremely fair and burns easily, I know that when I lived at 950 feet above sea level I could get away with wearing 25 or 30 sunscreen. I also know now, living at 7000 feet above sea level, I have to wear 45 or more.

  • SF Reader

    I’d like to see the melanoma signifier blacker. Melanoma is almost always associated with blue/black color not dark brown. Also, melanomas are not ~all~ “uneven looking” like your graphic. Some show up as perfectly round blue/black lesions. Because many of us were taught to identify melanoma by looking for irregularity in moles, it is sometimes unrecognized (even by doctors). Good job on fixing the melanoma graphs, now they are at the same scale, which was a definitely important fix.

  • dvj

    Thanks for your graph, it is a very confusing subject! Lack of UVA protection is the biggest problem with sunscreens, but the percentage of products that include it is increasingly rapidly. The best thing you can do is buy a sunscreen with one of the 4 or 5 proven UVA protecting ingredients in it. And slather.

    The UVA star system is voluntary and was developed by Boots, which licenses it to other companies in the UK (not used in the US). There is no European or US government standard.

    The following points regarding some of the dangers you list all come from a cosmetics consumer advocate in the US (Paula Begoun). She also now sells her own products (which contain these ingredients), and as such should be viewed skeptically. But you will see that she documents the scientific research to back up her counter-arguments. I have consistently found her to be the best source of compiled information and data about cosmetic ingredients. As much as I support non-profit consumer and environmental safety organizations, the Environmental Working Group (your source) does seem to have a record of overhyping the risks of some products, which I don’t think does anyone any favors.

    Oxybenzone has been extensively reviewed and overall found safe under real use conditions: http://www.cosmeticscop.com/cosmetic-ingredient-dictionary/definition/1040/index.aspx?filter=itemtype%3acontent

    As has retinyl palmitate: http://www.cosmeticscop.com/cosmetic-ingredient-dictionary/definition/1253/retinyl-palmitate.aspx

    You are probably much better off taking a Vitamin D supplement than dancing around in the sun for 20 minutes a day (and good luck with that in the UK): http://www.cosmeticscop.com/skin-care-facts-vitamin-d-supplement-sunscreen-use.aspx

    • david

      Thanks. This is excellently useful!

    • sunnyNphiladelphia

      This is disappointing:

      “The UVA star system is voluntary and was developed by Boots, which licenses it to other companies in the UK (not used in the US). There is no European or US government standard.”

      I am a fair-skinned ginger of european descent, so I have been liberal with my sunscreen for years, and avoid too much exposure – it’s disappointing to see the Jersey Shore types promoting tans and tanning; I predict it is going to have a damaging effect on many young people.

    • Chris

      Great point about the need to consider the level of risk. There are two factors: level of risk from exposure to ionizing radiation (UV) vs. level of risk from exposure to various chemical compounds used to block the radiation. People are traditionally very poor at risk assessment, especially with all the variables going on here, and it is especially hard when various groups list suspected correlations without providing any level of risk to make an informed decision.

    • Stef

      Actually, there are European government standards (stricter than the US) and recently (within the last month) the FDA has released its new labeling and testing requirements for sunscreens with new UVA requirements. (YAY – good for all of us!)

  • wxgirl

    Interesting. So what are melanoma survivors to make of this?

  • Murali

    This is unbelievable work……………

  • Niter

    One must consider that many sunscreens are not photo stable (and adding light stabilizers doesn’t completely counteract this, just prolongs the time to breakdown), so I don’t think that any sunscreen is going to give you more than 2 hours or so of protection. Certainly not the 5h40m of protection that an SPF30, according to the diagram, will give if used in adequate amounts.

  • RP

    Nice article!
    My single question / suggestion would be to indicate the UVA protection calculation method / relation to UVB protection.

    The UVB protection is calculated with SPF x skin type, which for average skin and a SPF of 8 gives 120 minutes (2h).
    The next graph then shows that, with a 5 stars (UVA) protection and enough quantity of suncream, one will get a combined protection of 1h48m (avg skin, 8 SPF, 5stars).
    That’s 90% of the protection time, calculated before. For the remaining protection levels (4 to 1 stars) it seems to be 80%, 60%, 40% and 20% respectively.

    Am i right in assuming this is the right method and is similar to different skin types… or I’m just plain wrong? :)

    Thanks again, that was a great way to put all this data!

  • hatestupidity

    WOW dvj… so that means it’s completely ok to put a chemical onto our skin that doesn’t need to be there!

    nice single-website authoritative reference by the way.

    the truth is; your skin is a living breathing thing. why put chemicals on it that don’t need to be there if we don’t have to?

    I personally will not use any sunscreen with Oxybenzone in it especially for my children. You can choose to do whatever you want…but I’m betting you also give your kids (if you even have any) sugar free drinks with loads of Aspartame in them. Don’t ya? well…why not…because the damn FDA says it’s safe of course.

    • Chris

      Whatever your decision, you are up against some environmental facts: UV light is “ionizing radiation” (breaks apart molecules). The greater the exposure, the greater the potential for DNA to be broken apart and mutate (cancer). I’m not saying that you should panic, but it is matter of trying to weigh long-term risks. There are non-chemical options, of course, like wearing long-sleeves, pants, never going in the sun, etc., but that might not be something some people are willing to do.

  • david

    WRONG! The SPF number is a diminishing return, especially in the upper extremes: i.e. SPF 100 is only a tiny bit more protective than SPF 50. It’s not a linear relationship between SPF number and protection. Really, anything over SPF 30 is basically a waste.

    • miriam

      Hi David,

      Have you got a source for that?

      Miriam
      Researcher, Information is Beautiful

    • K-eM

      Tell that to my sunburned body.

  • Alan

    Vitamin D isn’t magically absorbed by the sun. UVB rays affect the skin and Vitamin D is produced.

  • Michael

    I feel you may have brushed over the data in your references which shows that Melanoma rates have increased more in countries with higher adoption of sunscreen.

    Perhaps adding sunscreen sales in £ or $ per year to the melanoma incidence rates graph might be interesting – though inconveniently confusing.

    Also is the title of that graph spelt correctly?

    • david

      yeah I removed the extra Melanoma data to try reduce clutter on the diagram. It is an interesting point. I’ll try to factor it back in. Thanks! D

  • David

    Thanks for producing these but it never occurred to you to post or link to higher res versions?

    • david

      Sure. I’ll try to do that. I have to watch my server costs though.

  • Graham

    As someone who has worked in the field for a while (and had a hell of a time getting grants funded and papers published) the UVA vs. UVB causation of melanoma debate remains fierce. Mainly because different sides of the argument have legitimate data supporting their position, it is the extrapolation of this data to the human case that is often problematic.

    Different animal models, run in different ways, have shown different results in different hands. Some of these models have been albino in nature, some pigmented. Differing kinds of UV treatment protocols, differing kinds of melanomas induced.

    So it is difficult to really predict what happens in humans from models.

    Some things are clear to me though, melanoma is relatively very rare in albinos, showing melanin is important in some way to causing melanoma. If UVB were causing melanoma in these people (through direct DNA damage), you would expect a lot more melanoma. But heavily pigmented peoples are protected. A lot of human melanoma signature mutations are not typical UVB-induced lesions. Sunscreen studies have generally shown that they are not protective against melanoma. Tanning beds are becoming quite well linked to melanoma, and are generally UVA -enriched sources.

    Me, I use SPF 15 and make sure it has 3% stabilized avobenzone to get good UVA protection that is at least balanced to the UVB protection.

  • A

    it would have been helpful to follow up with some sunscreens that are safe, or that you would recommend. Also, is it not possible to get all of our vitamin D requirements from our food?

  • Allie

    Amazingly helpful article! As a member of the pasty people’s party, I’ve got bottles of sunblock stashed everywhere–going to print out your charts to put right alongside them :)

  • Anon

    Not everyone needs sunscreen though, particularly not if you grew up in a warmer climate. I’m a relatively-pale north Indian that grew up there, no family history of cancer despite that I doubt anyone’s ever owned a tube of sunscreen, and I’ve never worn any either in my life. I tan very easily, never burn even after a long day out. (I am a bit prone to sun-induced dizziness so I always wear visors though.)

    I do wonder what the skin cancer rates are like for Africans living in Africa. Or people in any tropical zone.

  • Horse

    Interesting that…

    EU SPF * UVA stars = combined protection in minutes

    …at least for one to four stars, assuming inadequate application.

    Also, any reason for using the Libyan link shortener for the link to the figures?

  • http://progurt.com robert beson

    The sun does not and cannot CAUSE skin cancer .
    The sun does not and cannot contribute in any way to the cause of skin cancer

    I would still make this statement even if 99 % of people alive today disagreed with me.
    The remaing 1% would eventually discover the cause of skin cancer and the world would again be a better place .
    I mean no disrespect to anyone with an opposing view. But for me and my family we will choose to think otherwise without causing any offense.

    • http://speaksocial.net Brad Bogus

      So what does cause skin cancer?

  • http://www.storytellingwithdata.com cole

    Great infographic. I just blogged about it: http://www.storytellingwithdata.com/2011/07/i-like-this-chart.html

  • Julio

    It is true that “thick clouds” considerably reduce UV on earth surface, but many cloudy days do not have such a big UV reduction. The infographic could be misleading for some people. Source: “Up to 80% of solar UV radiation can penetrate light cloud cover. Haze in the atmosphere can even increase UV radiation exposure.”, World Heath Organization, http://www.who.int/mediacentre/factsheets/who271/en/
    The infographic is good, but it could be improved.

    • david

      always up for improving it – thank you for the extra info – David

  • Greg

    This is topical isn’t it.

    The DTB have recently covered this at http://podcasts.bmj.com/dtb/2011/6/1/sunscreens/ and http://dtb.bmj.com/content/49/6/61.extract

    Also, SBM blog had a really good 2010 overview of this topic too at http://www.sciencebasedmedicine.org/index.php/the-great-sunscreen-cover-up/

    My only problem with the above is depicting heart attack victims in wheelchairs!

    Greg.

  • John

    The UV radiation that hits the earth is not ionising. The high energy ionising UV is absorbed by the atmosphere.

  • jen

    It should also be noted that Australia has much more stringent guidelines where sunscreen is concerned. I’ve been using Blue Lizard sunscreen for the past few years and find it to be leaps and bounds above a typical US sunscreen. My husband is an extremely pale redhead. He has “always burned” until he started using this sunscreen. Now he can be out in the sun all day with one reapplication mid-day and he remains as pale as when he walked out of the house.

  • Christopher

    What if you would like to get a little sun in the summer and darken your skin but would also like to protect against aging and a little bit against cancer.

    I think the graphs would be better (or simpler) if they were based on what your goals are.

  • http://speaksocial.net Brad Bogus

    I’ve been interested in this ever since the FDA increased the regulation on sunscreens. My parents know a guy who created a type of sunscreen called Tikkun ultra shield, and it was apparently the best stuff they’ve ever tried. I recently floated the river in New Braunfels, TX for the 4th and tried it for the first time. I put it on my face only (the 15 SPF kind), and I covered the rest of my body in some other name brand sunscreen, probably banana boat or coppertone, the 30 SPF kind. I added the name brand stuff 2 separate times on my body but left my face alone. After 4 hours on the river, my body was burned and my face was not. Pretty impressive stuff.

  • http://www.morethanorganized.net Miriam Ortiz y Pino

    Yeah, but is it ok to use a lower spf if you use the right amount and reapply based on the current wisdom and don’t go in the water? Also, you forgot to factor in altitude. I’m just saying.

  • Joy

    So according to my Better Homes & Gardens Magazine (not the most scientific source, I know) (June 2011), The American Academy of Dermatology says “[T]he risk of getting skin cancer is bigger than the risk of developing a [vitamin] D shortfall from using sunscreen,” and they recommend getting it through supplements or dietary sources.

  • SL

    The source of your information regarding sunscreen-ingredient dangers is Environmental Working Group (EWG). FYI, here is the Skin Cancer Foundation’s opinion of their data:
    “The EWG has their own system for evaluating things which is nothing more than junk science.”
    http://www.skincancer.org/sunscreen-criticisms-unfounded.html
    Link discovered via
    http://en.wikipedia.org/wiki/Oxybenzone

    • david

      great – we’re currently revising that section with some new evidence. We’re taking our time and being careful though as there’s both junk science *and* partisan science.

  • Rob Threeply

    “I’m calling it the Sunscreen Smokescreen.”

    Except clearly you aren’t !

  • Tyler

    I have to say my two contentions with this are about the last two graphics.
    For the first (“But is sunscreen harmful”) it is worth noting that the toxicity of compounds is dependent on dose and mode of exposure. Vitamin A, for example, is incredibly toxic when ingested at high levels (don’t eat bear liver). But it’s also an important compound for biochemical reactions in the body. I can’t speak for the other two substances you mention, but context is important.
    I’m really surprised to see the last figure. I agree that limited exposure is good for vitamin D synthesis, but the heart attack and mortality references are a stretch. Correlation does not indicate causation. There are obviously large differences between summer and winter other than the amount of sun. Perhaps its temperature, or weather blocking people from being active, or blocking family from visiting. There are innumerable other things that could account for this.
    Not to focus on the negative, I do like the information toward the top of the graphic. To me it seems like a simple and straightforward explanation of what SPF etc means and how to stay safe.

  • http://www.rossparker.com Ross Parker

    This graphic says both:

    1. 20 mins in the sun without sunscreen is good for you
    2. You should apply sunscreen before entering the sun

    These cannot both be correct.

  • acm

    yeah, what Ross said (and this is a big issue for infants, who often need vitamin D).

    thanks for the great data at your site — I had the opposite impression of cloudy days, so appreciate that, as well as the ingredients-to-miss list!

  • http://www.theunmom.com Keely

    Am I the only one who noticed this is titled “SunSCREAM Smokescreen”?

    Oh, Rob Threeply noticed too.

  • iamjoebob

    While there’s WAY TOO MUCH information here, I think I’ve been able to distill it down to a simple to understand equation:
    Determine the lowest protection rating necessary to protect your skin type.
    Apply a little more than you think you need.
    Reapply it every two hours.

    Based on the data here, that will have us reapplying the protection when we actually need it – not when we think we will, and balance the deleterious effects of the chemicals versus overexposure to the sun.

    It ain’t Rocket Surgery

  • Agg @ Ashmore

    Why can’t we buy 50+, Japan sells it and i have it sent over from there….
    Can some-one please tell me why we sell the lowest in sunscreen protection and Australians needs the hightest???????? Look how hard we had to fight just to get 30+
    is there something sinister here because i don’t understand the reasoning*****

  • Rene

    Hi Guys

    I think you had done a brilliant job with the graphs and this article, there will always be a few tweaks to be done as we learn more from each other. The thread of comments have been fantastic to read, I am just absorbing info. I was diagnosed a few months ago with Melanoma I am 27 years old and was brought up in South Africa. Currently on a type of chemo for the next 18 months. Stage 2 , 3 operations later , I am lucky to catch it early.We never had the awareness the Australians had growing up. We went to school with little or no sun tan lotion, played outside with out hats or protection, we played sports outside until 6pm every evening. The teachers let us burn out there and parents too. However it was just not part of our daily lives. If they did tell you to put sunscreen on it was because you might burn and have ugly skin when you get older. We used to put a little on while on the beach and did not think to keep putting it on. My melanoma is genetic they say, but so many people are dying of cancer thinking its just lung cancer or liver cancer , the source was actually Melanoma which spread. So really information is key to survival in countries like that, sadly our country is so focused on Aids that nothing else matters there. Thank you for all the information and I will be sure to pass it on knowledge is power !!!! Thank you , this is a young persons disease, that can be deadly , I would rather splash myself with Lotion and try to protect myself than use nothing!!

  • Emma

    too bad that the info provided regarding potentially “dangerous” ingredients included in susncreena is NOT accurate. The AAD (American Academy of Dermatology), the SkinCancer Foundation and many more of the biggest associations of dermatologists in the US have challenged the EWG report which is giving a very unacurate picture of the risks linked to the presence or not of those ingredients in a sunscreen. Please read the position paper of the AAD on this subject. Thanks http://www.aad.org/stories-and-news/news-releases/sunscreens-remain-safe-effective-form-of-sun-protection

    • miriam

      thanks for the link!

  • Ben Finney

    Great work, David!

    To make the information more beautiful, please don’t use the letter “X” for multiplication. Instead, use the correct character, U+00D7 MULTIPLICATION SIGN, which is “×”.

  • http://progurt.com robert

    If we knew what caused skin cancer we would not be blaming the sun

    The future will look back and laugh at us like
    we do at the thoughts and statements of the past

    Instead of putting on sunscreen why not sleep during the day and stay awake at night
    We could cure skin cancer this way

  • http://gregor.com gregor

    something that might be a little faster (just in case you didn’t know it already):

    http://www.wolframalpha.com/input/?i=time+to+sunburn

    but thanks for the nice graphics nonetheless :)

    • miriam

      thanks gregor – good source!

      Miriam
      Researcher, IiB