by Eduardo Ferreyra
The written media, TV stations, radio, and anyone that have a voice that can be heard, have been repeating what dermatologists, environmental NGOs, and public officials say, recommending not to expose to the sun rays between 10:00 am and 4:00 pm, especially since the "ozone layer problem had aggravated" and "destruction of the ozone layer allows greater amount of UV-B radiation to pass through the atmosphere", and that "there is the risk of contracting skin cancers, malignant melanomas and cataracts" Well. Nothing of the sort is true
To begin with, the problem of the ozone layer never existed . George Dobson, the scientists in whose honour the Dobson Units were named for measuring the concentrations of ozone in the infamous layer, demonstrated back in 1957 and 1958, that in the Antarctica was occurring a very peculiar phenomenon that he called the Southern Anomaly, which consisted in abysmal reductions in ozone concentrations in a region known as the Antarctic Polar Vortex. In 1957, during the Antarctic campaign made during the International Geophysical Year, Dobson was the first human being to measure the ozone levels in the Antarctic stratosphere. The same thing was being done by the French scientists at the Dumont D'Urville station, at the other side of the South Pole.
Curiosly enough, both teams of scientists got almost the same results, with a huge reduction in the stratospheric ozone concentrations, recording values down to 125 DU (Dobson Units, then called otherwise). Since then until today, ozone values in the Polar stratosphere have been comprised between normal averages, with greater concentrations during some years, and lower concentrations in others, following a pattern marked by diverse factors of natural origins as sunspot cycles, the Quasi Bi-annual Oscillation (the inversion of the Equatorial Stratospheric Winds every two years or so), and the El Niño and La Niña occurrences. These natural phenomena affect in a direct manner in the low stratospheric temperatures in the South Pole, and in the formation and power of the hurricane winds spinning around the Pole, known as the Antarctic Polar Vortex
As ozone concentrations varies in a natural way all over the world, according to the stations and months of the year, the hour of day, different altitudes, and different regions of the planet independently of the other factors, and as ozone concentrations have been stable over the years in spite of all Apocalyptic forecasts and claims made by the press and the environmental NGOs it can be said that the issue of the Ozone Layer and the infamous Ozone Hole is a spectacular fairy tale (better still: a Hoax) from which many corporations have filled their pockets, and other groups have increased their political power up to unsuspected levels.
Which brings us again to the official anouncements of Environment Ministries warning us that "Due to the destruction of the ozone layer, don't expose yourself to the sun because you'll be full of cancers and cataracts, etc, etc.", that tell us two quite grave things: One, they know nothing about atmospheric science (and they are in charge of the Environment!), and the other is: they completely ignore what scientists in their own National Meteorological Service send to their offices every week, as expressed by Lic. Victoria Taffuri, at Villa Ortúzar National Observatory, in charge of measuring ozone levels in Buenos Aires: "We have not recorded any decrease in ozone levels during the past 25 years". Serious double ignorance: their own scientists reports, and the basics of science. It makes us wonder: ¿Where are they leading us?
The authorities seem quite worried about the population getting cancers or cataracts because they exposed themselves to the sun. Because of this, they recommend not to do it between 10 AM and 4 PM because at that time of the day solar irradiation is higher. On this subject we agree, but only on this. About the rest, we completely disagree. Let us see why
Earth's atmosphere is a natural filter for the incoming solar radiation, but it filter radiations in different ways, according to their wavelenghts. Earth's atmosphere is composed of 78% Nitrogen, 21% Oxygen, and 1% of many gases, among them ozone, the famous shield against UV radiation. Nonsense! Ozone concentration in the atmosphere barely reaches 3 millionths parts per cent, in more understandable numbers: 0,000003%. By the way, in order for you to see how dense this protecting shield is, the 350 Dobson Units, normal for almost all parts of the Earth, (around the Poles the levels go up to 500 DU), means that if the ozone were compressed at sea level and normal temperatures, the thickness of the resulting layer would be the insignificant amount of 3,5 millimeters!. (mm) Such a powerfull shield we have!
Let's go back to the filtering issue: nitrogen and oxygen filter quite efficently electromagnetic radiations of short wavelenghts, as X-rays, gamma rays, and the UV range between 40 and 286 nanometers (nm) known as UV-C, but slowly they become less effective with longer wavelenghts as the UV-B (286-320 nm), UV-A (320-400 nm), the luminous radiation (400-700 nm) and then the longer wavelenght radiation as the infrared and the very, very long ones, the radio waves.
The longer the wavelenghts, the easier they penetrate the atmosphere. Because of this, the atmos-phere is virtually transparent to visible and infrared radiation, and in a great extent to Ultraviolet-A radiation, that reaches Earth's surface with entire freedom. And here is the main point in the issue: the differences between quantity and quality of UV-B and UV-A radiation, a fundamental thing if we want our health to remain as good as it has been until today.
UV-B radiation has effect on the interior of the cells and can affect their DNA, causing ruptures, changes and mutations. However, they have little penetration and don't reach deep into the dermis. Our body has a very effective defense mechanism against UV-B rays, and this is melanin, pigments floating in the dermis known as melanocytes. When UV-B rays activates them, melanocytes begin to travel upwards in the skin in order to block the intruding sunrays.
A well tanned skin, with abundant melanocytes near the skin surface is a pretty thing to see, especially in nordic people that sometimes resemble "Golden Semi-gods". A matter of fashion and nonsense. Among Latin Americans and Asians, the golden color have a tendency to disappear and it looks more like "ebony brown" that, although is not too "fashion", results much more convenient for the health. People of darker skins (or Mediterraneans that get tanned dark) have a lower rate of benign skin tumors, among which we can distinguish two classes: those affecting the "basal" cells (the so called "basal cell tumors"), and those affecting the squamous cells, known as "squamous cell tumors" (what else did you expect?). These tumors rarely produce metastasis and they are rapidly and easily cured. However, the solution is always surgical: they have to be removed, although it takes few minutes to do it.
There is another kind of skin tumor known as malignant melanoma, precisely because in most cases it leads to the patient's death. -if it is not diagonsed early and immediately removed. It is good to know that melanomas appear frequently in body areas that are never (or almost never) exposed to the sun, as the interior of the mouth, the buttocks, feet soles, armpits, etc. This peculiarity, and the fact that black people, highly protected from the benign tumors (basal and squamous cell, whose rate of incidence is almost null among them) have the same incidence rate of melanomas as the lighted skinned people or the mediterraneans.
What does this means? Melanomas are not provoked by exposure to the sun, while basal and squamous cell tumors are always due to excessive exposing to the sun rays during years of consecutive holidays in beaches and mountains, or a constant work outdoors, as farmers. While benign tumors are more frequent among farmers and outdoor working people, melanomas are more frequent among people working indoors and people living in the cities. Why? Not even the most knowledgeable dermatologist in the world knows why, as they don't know which are the causes of melanomas.
And then, misinformation spreads and people is led to believe that if one exposes himself to the sun it will contract cancer and will die, or one will develop cataracts and will go blind. Nonsense, again! Cataracts develop in people after they are over 50 or 60 years old, some people will never have them, it depends of their genetic structure and some factors (occupational, in most cases, as careless electric welders, mountain climbers, skiers and surfers who refuse to wear goggles or dark lenses) but a normal exposure to sunrays hardly will be a preponderant cause for cataracts, especially in a "fashion" society that has the fixation of usig dark glasses even inside discoteques.
But, even if the UV radiation would increase 100%, neither the benign skin tumors nor the cataracts will increase their incidence rate. It seems hard to you to prove this? Let's see. UV radiation increase from the Poles to the Equator about 5,000% (yes, five thousand percent!) due to the Earth's curvature, and the longer path that solar rays have to travel before reaching the surface in the Polar regions. This means that the sun shines 50 times brighter in Quito, Ecuador, than in Tierra del Fuego.
According to very accurate measurements, UV radiation increases 1% every 10 miles (16 km) you travel towards the Equator, thus it doubles (100% increase) for every 1000 miles (1600 km). On the other hand, UV radiation increases 1% for every 50 meters (147 feet) in altitude, so values at sea level are doubled (100%) at 5,000 meters (15,000 feet). In general terms, in the healthy Pampa de Achala in Cordoba, Argentina, 2200 meters above sea level (6,600 feet) UV radiation is 50% higher than in Buenos Aires. The distance from Buenos Aires to Salta is about 1500 km (900 miles), so in Salta there is normally 100% more UV radiation falling on unaware men, children, women, cats, and dogs than in Buenos Aires. As there are another 600 km more to Santa Cruz de la Sierra, Bolivia, the "cruceños" are getting 150% more radiation than the "porteños". And the inhabitants of Quito, Ecuador, they get 200% more for living in the Equator line, and an additional 60% for their 2,800 meters altitude. See in Figure 1 the way in which the UV radiation varies in cities of different latitudes, from Panama to Tromso, in Norway. Why don't the travel agencies tell their Norwegian clients that they will get an extra 500% increase in their daily ration of UV when traveling to their Caribbean holidays? Marketing strategy.
Once checked the validity of this data, we open the medical statistics book and find that neither cataracts nor melanomas are more abundant in Quito, Santa Cruz de la Sierra or Salta, than they are in Buienos Aires, Cordoba, or even Ushuaia, Tierra del Fuego. What kind of mystery is this? The mystery is unveiled when science provides the data, and not the press realeases by "axe grinding" environmental NGOs, avidly picked up by sensationalistic media (Is there any that is not? But let us take a step further.
Figure 1: Variation of Ultraviolet Levels in Different Latitudes of the World
Source: "The Holes in the Ozone Scare", R. Maduro, y F. Schauerhammer, 1993.
The UV radiation levels increase by several orders of magnitude from Tromso, Norway to Panama, in the Caribbean.
(Graph taken from the Spanish version of this website)
Why It Is Safer at Noon?
It about a mathematical issue. Many studies have demonstrated that melanocytes are activated to their maximum ascending speed by a daily 20-30 minutes dose of UV-B, depending on the different kind of skins. If we take a look at Figure 2, the graph will show at the top the time of the day, from 6:00 am to 6:00 pm, 12 hours of average insolation at the Equator. At the left side, there are the UV radiation values (given in watts/m2) falling over the sea surface.(multiply this value by the altitude factor corresponding to other locations.) The radiation falling at noon over Buenos Aires is an average of 350 watts/m2 (at the same moment there are barely 150 watts/m2 over Tierra del Fuego, measu-rements taken when there was a "mini-ozone hole" above Ushuaia, (study performed by Argentine scientists Isidoro Orlansky and Ernesto Martinez, from LAGE, (Laboratory of Geophysics at the Buenos Aires National University.)
Figure 2: UV-A and UV-B Radiation Doses at Different Times of the Day
Infograph by the author.
Because UV-B radiation is almost completely filtered by the atmosphere during the early and late hours of the day, the values increase at a non-linear manner until almost noon; then there is a small plateau of about two hours, and then they start to decrease until they disappear when the sun settles down. This is the reason behind the authorities' recommendation for exposing to sunrays before 10:00 am and after 4:00 pm, without knowing too much if the hour they recommend is +3 or +4 GMT (Greenwich time).
In Figure 2 there are 3 cases presented: in case 3 (at noon), you can have the basic dose of 350 watts/m2 needed for just 20-30 minutes because it is the moment of maximum insolation. Any dose received beyond those 20-30 minutes will not speed up your tanning, and will harm your skin.
In case 2 it is needed almost an hour to get the same dose of UV-B that will send your melano-cytes up the dermis. In the same way, any exposure beyond that hour, will double the harm your skin gets, and won't make you any darker.
At last, in case 1, taking sun from 7:00 am you'll need about 1:45 hours for getting the same results as given by 20-30 minutes at noon. You can do it, however, but the speed or amount of tanning won't be increased at all. In any of these cases -and this is important- get away from the sun and look for shelter in the shade and stay there. The EXCESS in exposing yourself to the sun is harmful and could be dangerous (skin burns are not nice; they hurt and can become infected or lead to other serious troubles). In this issue Common Sense is the primary factor to have in great amounts. To be prudent is the advice, but don't take this to the extent of becoming a neurotic. And here comes another explanation you should know about.
The intensity of UV radiation reaching Earth's surface is, in average, 1000 watts/m2, of which 350 watts correspond to UV-B and 650 watts to UV-A. UV-B rays mainly have chemical activity over the cells, and they are essential for the synthesis of Vitamins E and D on the skin surface. These vitamins serve as antioxidants and fix calcium in the bones.Little exposure to UV rays during childhood leads to a deficiency in Vitamins E and D, thus to ricketts (an endemic disease among poor children in London, back in the late 1700s and mid-1800s). In elderly people, the problem of osteoporisis is aggravated if they lack the adequate amount of sunrays for fixing the calcium (that they receive as dietary supplement) to their bones. The lack of antioxidants as vitamin-E, synthesized at the skin surface by UV-B radiation and absorbed through the skin, increases the risk of cancers, normal at advanced age. Thus, it is important to make sure that you get the adequate and necessary UV-B radiation, in spite of what radios, newspapers and television tell us.
While our body has the ability to warn us when we have received an excess of solar radiation (erythema) it has not the hability to tell us when we are not getting enough of the essential UV-B radiation unless "the paleness of your skin" is something more than a musical hit, and we should consider it a warning of imminent risk of lack of calcium in our bones. Furthermore, the UV-B radiation has bactericidal and antimicrobial properties that represent a great saving in medical and hospital bills.
Look again at Figure 2, and see that UV-A radiation has almost the same intensity from 7:00 am until 6:00 pm (always at the Equator), because the atmosphere, as we have just learned above, is transparent for this radiation, and almost does not filter it. Then, contrary to what happens with UV-B rays, when we expose ourselves in early hours of the day or late in the afternoon, as our loving and caring authorities recommend us we must be exposed to sun rays more time than we would be at noon for getting the same tanning effect. Taking sun early in the morning increases our exposure to the more dangerous UV-A rays, because they are responsible for the cases of benign tumors (but not of melanomas, as we saw above) and the damage to skin cells is irreversible. If you want to look as a little old man in very short time (or little old woman -forgive me, ladies), simply go along with the media and dermatologists advice, and especially the neuro-eco-pesimistic NGOs that want you to live frightened and support their causes, because they are "the good guys" and they want the good for everybody. Amen.
¿What About the Sun Blocking Creams?
They only have very specific applications, as is the case of those who are forced to stay long hours under the sun. And they should use those creams that ALSO block UV-A rays, that are just new in the market. It seems that at last, and many years of struggling in this issue, US dermatologists have become aware that the really dangeorus rays for the skin are UV-A and not so the UV-B. This does not mean that you can take long UV-B baths because that would be suicidal. Not so much, but not so little, as the Spaniards say. The Golden Rule of Toxicology still is the same, and applies here: "THE DOSE MAKES THE POISON", or as my grandmother used to say, "A little fattens you, too much annoys".
I was almost forgetting: the body has two mechanisms, quite effective, for protecting us from sun rays. One is a WARNING mechanism called erythema. It is the red color our skin develops when we stay too long under the sun. It is our body that is telling us: "Boy, let's stop this killing, it's shade time". The other is the DEFENSE mechanism represented by the melanocytes going up to the skin surface. When we use sun-blocking creams we are dodging or bypassing our natural defenses: the skin does not get red and people keeps under the sun believing they are safe. As the diminished UV-B don't activate the melanocytes, the UV-A rays have free entrance to the interior of the dermis to start doing a massacre on the cells. A basal or squamous cell tumor is risng in the horizon... This is criminal!
They are few, and don't you ever forget them. If you wanto to get a beautiful and healthy tan, and don't want to run risks with your skin:
- Expose yourself to the sun rays between 10.00 am and 3:00 pm but ONLY FOR 20 o 30 MINUTES!
- Don't use sun-blocking creams. You can use skin hydrating creams before and after going into the sun. Old tanning oils with coconut, jojoba, palm, etc, oils can be used because they do not block UV-B or UV-A rays. They don't serve for much, but at least they are not harmful, and don't make you think you are safe.
- Use a large winged hat (no baseball caps, please), long-sleeved T-shirts or shirts, light trousers, etc, when you must stay a long time under the sun, and then (and only then) the use of sun-blocking creams are justified. But, if you can avoid staying long time under the sun, do it!
- The UV-B radiation that the sun sends us is HEALTHY and even INDISPENSABLE, but IN FAIR AMOUNTS . Excess will always lead to catastrophe. Be cautious. Don't be a fool.
- Don't believe in what the authorities, radios, TV, or NGOs tell you (their main "raison d'etre" is stealing money from you), nor to anyone that is unable to explain things to you with proved scientific evidences.
- Enjoy life and, if you can spare it, pay your taxes. The Country will be grateful..
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