Ultraviolet Protection after a Nuclear War


UV Protection after a Nuclear War
by Bruce Beach
Radiological Scientific Officer
Table of Contents
Foreword

Because I have been asked about this subject several times, and because there will be a need for this information after a nuclear war, and because there does not appear to be anywhere that I can find a document on this subject - I have decided to write up this material myself.
For any who may decry my lack of expertise in this area, I will certainly accept their reservations and only ask that they provide me with a better article for posting. 

 Why there is little information on nuclear UV
 
Between the opposite extremes of Greenhouse Effect and Nuclear Winter many dire threats encircle mankind and many of these threats are not by any means mutually exclusive. While we will not concern ourselves here with the environmentalists' pet concern of Greenhouse Effect and shall confine ourselves to one particular subject associated with Nuclear Winter let us note that the non-availability of survival information is created by two extremes of thought.
One extreme of thought is characterized by the governments and their many bureaucracies that for the most part, for two reasons, sneeringly and condescendedly reject any requests for information.
The first reason is that they hold it ridiculous that anyone would think after all these years without there having been a nuclear war that nuclear weapons would actually be used and that anyone should prepare for that eventuality. The second reason is that they become annoyed that a civilian (in their terminology not meaning someone who is non-military, but rather simply someone who is not representing a government agency) would encroach upon their domain and ask for information. These government attitudes are passing strange in that they are the ones who are supposed to be concerned about the well being of the public and they are ones who spend seemingly endless billions of dollars in building nuclear weapons and the means of their delivery while saying that they will never use them - so that we need not worry about them.
The other extreme of thought holds that use of nuclear weapons will be so disastrous that there is no need to make preparation for survival.

      The intuition of the average human being since the first use of these weapons against population centers has been that a nuclear war would cause the extinction of our species. In light of recent studies, it appears that this intuition is much closer to the truth than the enlightened understanding of those who have advocated doctrines of the survivability and therefore fightability of a nuclear war.
      [Birks, J. W., J. Staehelin, and S. L. Stephens. 1985.
      Changes in tropospheric composition and chemistry
      resulting from a nuclear war.]
The rational for this latter doctrine is that the holders of it equate "survivability and therefore fightability" and therefore anyone who advocates 'survivalism' receives also their sneers, and more than that - their downright anger because to them we seem to be advocating nuclear war. While this latter accusation couldn't be further from the truth we still end up with the same result - the academic and technical talent on both sides give us no assistance in making preparation for nuclear survival.


The Meaning of Nuclear Winter

      Those of us who were involved in peace activities in the 80's probably remember a good deal about nuclear winter. Those who have become involved later may have heard little about it. No scientific study has been published since 1990, and very little appears now in the peace or nuclear abolition literature. *It is still important.* With thousands of rocket-launched weapons at "launch-on-warning", any day there could be an all-out nuclear war by accident. The fact that there are only half as many nuclear bombs as there were in the 80's makes no significant difference.
      Deaths from world-wide starvation after the war would be several times the number from direct effects of the bombs, and the surviving fraction of the human race might then diminish and vanish after a few generations of hunger and disease, in a radioactive environment.
      *The concept of Nuclear Winter*
      Bombs directed at missile silos would burst at ground level and throw a huge amount of dust into the atmosphere, as the explosion of a volcano does. It is as much as a million tonnes from a large nuclear bomb bursting at ground level.
      Bombs bursting over cities and surface installations, like factories or oil stores and refineries, would cause huge fires and fire-storms that would send huge amounts of smoke into the air.
      The 1980's research showed that the dust and the smoke would block out a large fraction of the sunlight and the sun's heat from the earth's surface, so it would be dark and cold like an arctic winter. It would take months for the sunlight to get back to near normal.
      The cloud of dust and smoke would circle the northern hemisphere quickly. Soon it could affect the tropics, and cold would bring absolute disaster for all crops there. Quite likely it would cross the equator and affect the southern hemisphere to a smaller degree.
      While the temperature at the surface would be low, the temperature of the upper part of the troposphere (5-11 km) would rise because of sunlight absorbed by the smoke, so there would be an absolutely massive temperature inversion. That would keep many other products of combustion down at the levels people breathe, making a smog such as has never been seen before. PYROTOXINS is a word coined for all the noxious vapours that would be formed by combustion of the plastics, rubber, petroleum, and other products of civilization. It is certain that these poisons would be formed, but we do not have quantitative estimates. The amount of combustible material is enormous, and it would produce dioxins, furans, PCB's, cyanides, sulphuric and sulphurous acids, oxides of nitrogen, carbon monoxide and carbon dioxide in amounts that would make current concerns about atmospheric pollution seem utterly trivial. There would also be toxic chemicals like ammonia and chlorine from damaged storage tanks.
      Altogether, nuclear winter would be an ecological disaster of the same sort of magnitude as the major extinctions of species that have occurred in the past, the most famous one being 65 million years ago at the cretaceous extinction. Of all the species living at the time, about half became extinct. The theory is that a large meteor made a great crater in the Gulf of California, putting a trillion tons of rock debris into the atmosphere. That is a thousand times as much rock as is predicted for a nuclear war, but the soot from fires blocks sunlight more effectively than rock debris. In nuclear winter there would also be radioactive contamination giving worldwide background radiation doses many times larger than has ever happened during the 3 billion years of evolution. The radiation would notably worsen things for existing species, though it might, by increasing mutations, allow quicker evolution of new species (perhaps mainly insects and grasses) that could tolerate the post-war conditions.

      NUCLEAR WINTER REVISITED
      by Dr. Alan Phillips,
      October 2000
      This nuclear winter effect is the exact opposite of the greenhouse effect which maintains most of the Earth's surface at above-freezing temperatures during the warmer seasons. Nuclear winter would have its greatest impact if the nuclear war occurred during the summer, because the incremental change in the amount of sunlight that would reach and warm the Earth's surface would be greatest then. Furthermore, during summer plants are not in their dormant states and would be most vulnerable to subfreezing temperatures. Of course, it is not possible to predict the season in which a nuclear war might break out.
      (In) some of the most sophisticated computer model calculations of the climatic effects of a nuclear war ... temperature perturbations are calculated to be in the tens of degrees Celsius, and in a fully interactive model the atmospheric lifetime of the particulate matter is enhanced so that the duration of nuclear winter would be at least a few months.... (and would result in) the partial destruction of the protective ozone layer, with a consequent increase in the level of biologically damaging ultraviolet radiation that would impinge on the biosphere once the smoke cloud has subsided.

      [The Medical Implications of Nuclear War,
      Institute of Medicine.
      1986
      by the National Academy of Sciences.
      National Academy Press, Washington, D.C.
      Possible Toxic Environments Following a Nuclear War
      JOHN W. BIRKS, PH.D., and SHERRY L. STEPHENS
      University of Colorado, Boulder, Colorado]
      Dust lofted by the clouds generated by atomic bombs and especially smoke from fires in cities, forests, industries, and oil refineries would darken the sky. A simple calculation, in which one takes the total amount of smoke (about 200 million metric tons) that might be introduced into the atmosphere by the nuclear war fires and distributes it uniformly over the middle half of the Northern Hemisphere, indicates that more than 99 percent of the sunlight would be absorbed by the smoke cloud.
      [Crutzen and Birks, 1982;
      Turco et al., 1983;
      National Research Council [NRC], 1985]
Ninety-nine percent of the sunlight being absorbed would make it rather dark so that we may say that these are literally dark days that are anticipated. Anyway, so much for statements regarding the threat of Nuclear Winter. However, two caveats may be made here from a survivalist's point of view. In the first place we do not know how intense it may or may not be. Some event or intervention may occur to ameliorate the final outcome.
      Matthew 24:22
      And except those days should be shortened,
      there should no flesh be saved:
      but for the elect's sake those days shall be shortened.
The other caveat is that because this shall be an unique event we really have no experience to tell us how and it what way other factors may interplay. Consequently, while it may be a severe challenge to agriculture and survival - it may not be an insurmountable one and thought should be given to strategies to combat its effects. That, however, is beyond the scope of the present study and will have to be treated of elsewhere. Here we are concerning ourselves with one particular phenomena that may accompany nuclear winter and that is the intensifying of UV (ultraviolet rays) from the sun. 

Intensified UV


      Another bad environmental thing that would happen is destruction of the ozone layer. The reduction in the ozone layer could be 50% - 70% over the whole northern hemisphere - very much worse than the current losses that we are properly concerned about. Nitrogen oxides are major chemical agents for this. They are formed by combination of the oxygen and nitrogen of the air in any big fire and around nuclear explosions, as they are on a smaller scale around lightning flashes. So after the smoke cleared and the sun began to shine again, there would be a large increase of UV reaching the earth's surface. This is bad for people in several ways, but don't worry about the skin cancers ? not many of the survivors would live long enough for that to matter. UV is also bad for many other living things, notably plankton, which are the bottom layer of the whole marine food chain. There would likely be enough UV to cause blindness in many animals. Humans can protect their eyes if they are aware of the danger. Animals do not know to do that, and blind animals do not survive. Blind insects do not pollinate flowers, so there is another reason why human crops and natural food supplies for animals would fail.
      [NUCLEAR WINTER REVISITED
      by Dr. Alan Phillips, October 2000]
This last quote does not clearly delineate why nuclear war survivors will not live long enough to concern themselves about the effect of UV in causing skin cancer but I thoroughly cover elsewhere my projections of the effects of an all out nuclear war on the world's population and in point of fact I am more pessimistic about the number of casualties than are most other sources who put them at about one billion people, or about 20% of the world's present population, whereas I put them at 80% or four billion of the world's present population. This still leaves 20% long term survivors or one billion people which is more population than the world had in 1800. I shall now turn to one summary source of scientific literature that I do have available and the following quotes, unless otherwise indicated, are from that source - which is:
ENVIRONMENTAL HEALTH CRITERIA 160
ULTRAVIOLET RADIATION
An Authoritative Scientific Review of Environmental and Health Effects of UV,
with Reference to Global Ozone Layer Depletion
Published under the joint sponsorship of the United Nations Environment Programme,
the International Labour Organisation,
and the World Health Organization Geneva,
1994
The document itself is very long (hundreds of pages), often very technical, and involves many chapters. It is mainly concerned with two areas of inquiry one being what we have referred to as the Greenhouse effect and the other being industrial uses of UV. The document concerns itself extensively with biological and medical studies. There is, however, little in the document relating directly to nuclear war and its effects.
      The sun is the principal source of exposure for most people. Solar UV undergoes significant absorption by the atmosphere. With depletion of the stratospheric ozone people and the environment will be exposed to higher intensities of UV. The consequences of this added UV exposure are considered so serious that it was a major topic for discussion at the World Environment Conference, held in Rio de Janeiro in 1992.
While the above quote refers to the environmentalists' concern about the Greenhouse effect, speculated as being caused by present human activity, the effects of a nuclear war on UV penetration could be much more substantial.  

Technical Explanation of UV
 
UV is split into three categories or wavelengths:
      UVA
      UVB
      UVC
Collectively they are all-adjacent in the electromagnetic spectrum and are just referred to as UV. It is the longer wavelengths that concern us and when in this article I refer to UV I am really referring mostly to UVA although sometimes UVB will be discussed.

      UVC is almost completely absorbed by ozone and oxygen in the atmosphere; even with severe ozone reduction UVC would still be effectively absorbed by the remaining oxygen. UV is one of the non-ionizing radiations in the electromagnetic spectrum and lies within the range of wavelengths 100 nm (which corresponds to a photon energy of approximately 12 eV) to 400 nm. The short wavelength limit of the UV region is often taken as the boundary between the ionizing radiation spectrum (wavelengths < 100 nm) and the non-ionizing radiation spectrum.

Optical Radiation Spectral Bands
Ultraviolet radiation 100 - 400 nm
UVA 315 - 400 nm
UVB 280 - 315 nm
UVC 100 - 280 nm
Visible radiation (light) 400 - 760 nm
Infrared radiation (IR) 760 - 10 / 6 nm = 1 mm
      UV of wavelengths less than 180 nm has no direct biological effect on humans since it is effectively absorbed in a few centimetres of air.
Methods for measuring UV 

The National Weather Service method for measuring UV


      Q: Why did the National Weather Service, the Environmental Protection Agency and the Centers for Disease Control and Prevention develop the UV Index forecast?
      A: Since the National Weather Service, the Environmental Protection Agency and the Centers for Disease Control and Prevention began offering an experimental UV Index on a limited basis on June 28, 1994, the effort has raised the visibility of the risks associated with prolonged exposure to ultraviolet radiation. Providing warnings, advisories and information to protect life and health is one of the prime elements of the mission of the National Weather Service. The NWS, EPA and CDC developed the UV Index in response to the increasing incidence of skin cancer, cataracts, and other effects from exposure to the sun's harmful rays. It is important that the public be educated on the factors that can affect UV radiation so preventive measures can be taken.
A very kind gentleman at:
      NOAA/National Weather Service
      National Centers for Environmental Prediction
      Camp Springs, MD 20746
has provided me with the following information:
    The conversion from Erythemal Dose rate to UV Index is as follows:
      an Erythemal Dose Rate of 25 milliWatts/sq meter equals 1 UV Index unit.
    For instruments that output in MEDs the common conversion is this:
      1 MED per hour equals 58 milliWatts/sq meter equals 2.3 UV Index units.
If you have questions about health aspects contact the U.S. EPA at 1-800-296-1996. If you have questions about scientific aspects contact the NWS at (301) 713-0622. 
 
Other methods for measuring UV



      UV radiation at the earths surface is measured using two methods 1. The first method measures the amount of energy contained in the UV radiation that reaches the Earths surface.
      The Department of Geography and Environmental Studies at The University of Tasmania uses this method to measure and record UV information. The method expresses energy using S.I. (Système International) units. In this case milliWatts per square meter (ie each square meter of a horizontal surface receives x milliWatts of energy. The SI symbol is mW m-2 . The graphical display of daily UV shown during TV weather bulletins is based on this data.
      2. The second method of measuring UV is based on the response of human skin to UV radiation and is recorded as a Global Solar UV-Index.
      This Index was developed as part of a plan to standardise UV radiation reporting around the globe. It is often used as a prediction, as is the case in Tasmania. The UV Index is determined for the one hour when UV radiation intensity is at its peak. This will generally occur at solar noon (approximately 1 pm during daylight saving time). The UV Index directly takes into account cloud cover and other environmental factors. Of course a predicted Index value is only that, a prediction, and must be treated as such.
      The measurements of UV radiation have been related to exposure categories based on sun burning times for fair skinned people as follows;
      milliWatts per square meter Index value Exposure Category < 60 Les than 3 Moderate 60 - 150 3 - 6 High 151 - 580 6 - 10 Very High > 580 Greater than 10 Extreme
      If there is 60 milliWatts of incident UV radiation (UV-Index of 3), a fair skinned person will experience minimal skin redness after one hour in the sun. If there is 151 milliWatts of incident UV radiation (UV-Index of 6) a fair skinned person will experience minimal skin redness after 24 minutes in the sun. If there is 580 milliWatts of incident UV radiation (UV-Index of 10) a fair skinned person will experience minimal skin redness after 6 minutes in the sun. While the extreme Category is a very rare occurrence in Tasmania, UV levels of over 250 milliWatts per square meter are common and will resulting in a fair skinned person burning after 15 minutes in the sun. Remember potential long term health effects from UV radiation do not depend on skin type.
MEDs (minimum erythemal doses)

Of the two useful means of measurement of the intensity of UV described above the second appears most practical for our use and is calibrated in a unit called a MED.

      An MED is the radiant exposure of UV that produces a just noticeable erythema on a previously unexposed skin. 200 - 300 J m-2 effective is the value of 1 MED.
Number of MEDs in a 3 h exposure period for a sensitive skin type (1 MED = 200 J m-2 effective) for the erythemally effective UVB irradiances are given in the following as a function of latitude (°) and time of year for the Northern Hemisphere (Driscoll 1992). We might think of this as being what is 'normal' in the a pre-nuclear holocaust period.
LATJanFebMarAprMayJunJulAugSepOctNovDec
0121414121111121315131212
5111313131212121314121111
1011121213121213141312119
15811111212121313121187
20710101213131312111076
25579101112121110855
30468101012111010653
3524689101098532
402358810997421
45124679875211
50113568864210
55012457643100
60011346542100
65001235421000
70001134321000
75000123210000
80000112110000
85000011100000
90000011100000
      Outdoors, exposure to UV constantly changes during the day. People are largely unaware of the degree of these changes. At noon, when the sun is overhead, the level of UV at a wavelength of 300 nm is ten times greater than at either three hours before (9 am) or three hours after noon (3 pm). An untanned person with fair skin may receive a mild sunburn in as little as 25 minutes at noon (depending on the time of year and the latitude) but would have to lie in the sun for at least two hours to receive the same dose after 3 pm. The global biologically effective UV falling on a horizontal surface occurs primarily during the midday hours, about 50% during the four hours centred on noon-time zenith (Sliney, 1987). Increased levels of UV due to ozone layer depletion may have serious consequences for living organisms. A 10% reduction in ozone could lead to as much as a 15-20% increase in UV exposure depending on the biological process being considered.
As an extrapolation of this last statement might we then say that as a worst case - a 100% depletion of the Ozone layer would result in a 200% increase in the UV exposure and from the table above - the worst case would be 45 MEDS (in the 3 hours centered on noon) or 15 meds per hour - or that one could receive a sunburn from being outside just 4 minutes at that time even on a dark cloudy day. Mind you, that is the worst case extrapolation of the maximum ozone depletion combined with the most critical geographical location and the time of day for the most intense exposure. Nevertheless, starting with this most extreme case we can then work downward in developing our defenses. Those who do not like my methodology can propose their own. 

Variables affecting UV intensity


There are many variables that affect UV intensity.

      The sun is the main source of UV. The broad spectrum and intensity of UV from the sun are due to the high temperature at its surface and its size. The intensity of solar UV reaching the earth's atmosphere would probably be lethal to most living organisms on the earth's surface without the shielding afforded by the atmosphere. Solar UV undergoes absorption and scattering as it passes through the earth's atmosphere with absorption by molecular oxygen and ozone being the most important processes. The ozone layer prevents almost all UV of wavelengths lamda < 290 nm and a substantial fraction (in excess of 90% of the total energy) from 290 - 315 nm from reaching the earth's surface. Thus the terrestrial environment is exposed to UV between 290 nm and 400 nm. The presence of cloud cover, air pollution, haze, or even scattered clouds, plays a significant role in attenuating UV. UVB and UVA irradiances are reduced due to scattering by water droplets and/or ice crystals in the clouds. Clouds can block a significant portion of the UV which would have otherwise reached the surface. Cloud cover and type are highly variable. The transmission of UV radiation through clouds depends on cloud height, type and optical density.
      Ozone depletion effects
      Over 90% of the total atmospheric ozone resides in the stratosphere (the upper atmosphere). The total ozone column is important for filtering solar UV. Only UVB is affected by changes in the ozone column.
There are many other variables such as:
deserts
grassy surfaces
water
snow
high altitudes
all of which increase the intensity of the UV reflected. Snow, sand and water are all reflective surfaces and will intensify UV exposure to varying degrees. Grass reflects from 2.5 to 3 percent, sand reflects 20 to 30 percent, snow and ice 80 to 90 percent. Depending on the angle of reflection, water can reflect up to 100 percent of rays striking the surface.
Speculation as to how much UV may be presented or present is largely useless. What will be needed is a reliable method of measure. We shall examine both methods of measure and methods of defense in later sections, but first let us look at the effects of intensified UV. 

Medical Effects of Intensified UV

 
Excessive UV, even under 'normal' conditions, can cause serious serious physical problems. We can only speculate what it might do under the extreme conditions of Nuclear Winter.

      Chronic skin changes due to UV consist of skin cancer (both melanoma and non-melanocytic), benign abnormalities of melanocytes (freckles, melanocytic naevi and solar or senile lentigines), and a range of other chronic injuries resulting from UV exposure to keratinocytes, blood vessels and fibrous tissue, often described as "photoaging" (solar elastosis). The worldwide incidence of malignant melanoma has continued to increase. The acute effects of UV on the eyes consist of the development of photokeratitis and photoconjunctivitis, which are unpleasant but usually reversible and easily prevented by appropriate eyewear. Chronic effects on the eye consist of the development of pterygium and squamous cell cancer of the conjunctiva and cataracts. There is evidence that ionizing radiation and UV may act synergistically in causing skin cancer.
      DNA is the most critical target for damage by UVB and UVC radiations. Cell death, chromosome changes, mutation and morphological transformations are observed after UV exposure of procaryotic and eucaryotic cells. Many different genes and several viruses (including HIV) are activated by UV exposure.
      Acute effects on the skin consist of solar erythema, "sunburn", which, if severe enough, may result in blistering and destruction of the surface of the skin with secondary infection and systemic effects, similar to those resulting from a first or second degree heat burn.
      Ethnic background is an important determinant of risk of nonmelanocytic skin cancer in Caucasians who are the most sensitive to the adverse effects of UV and the ones least likely to tan well.. Blue eyes, fair or red hair, and pale complexion in people of European origin are well established risk factors for melanoma. Nonmelanocytic skin cancer is much less frequent in populations with dark skins than those with light skins (Fitzpatrick & Sober, 1985; Hoffman, 1987; Urbach, 1987).
      The induction of immunosuppression by UVB has now been demonstrated in humans, not only those of light pigmentation, but also deeply pigmented individuals. This places all of the world's populations at risk of the potential adverse impacts of UVB on the immune system, including possible increases in the incidence or severity of infectious disease.
      Both UVA and UVB have been shown to mutate DNA and cause skin cancers in animals (Staberg et al., 1983). UVA penetrates deeper into the skin than UVB and because of the energy distribution of sunlight and filtering by the outermost layers of the skin, melanocytes receive up to 70 photons of UVA for every photon of UVB.
Agricultural effects of Intensified UV

      The production of phytoplankton has been estimated at about 6 x 1014 kg (UNEP, 1989). A loss of 10% would far exceed the gross national product of all countries in the world, assuming any reasonable price for biomass on the market. Field and laboratory experiments on plant responses to increased UVB radiation underscore the concern for agriculture, forestry and natural ecosystems as the stratospheric ozone level is depleted. Growth and photosynthesis of certain crop plants can be inhibited even under ambient levels of UVB radiation. Certain environmental factors, both biotic (e.g. plant diseases and competition with other plants) and abiotic (e.g. carbon dioxide, temperature, heavy metals, and water availability) can alter UVB effects in plants. This increases the difficulty in making any quantitative predictions. Plants in temperate regions and certain tropical species were found to be adversely affected by enhanced UVB radiation. Marine ecosystem which provides the primary food for human consumption (in some countries) has been shown to be more sensitive to UVB than terrestrial plants. One consequence of loss in phytoplankton is reduced biomass production which would be propagated throughout the whole food web. The marine phytoplankton is a major absorber of atmospheric carbon dioxide. Any reduction in this population would decrease the uptake of carbon dioxide and so augment the greenhouse effect.
Beneficial effects of UV

Some amounts of UV are beneficial in the same way that some amounts of arsenic are beneficial (in fact necessary).

      For the entire system of vitamin D3 production the amount of UV radiation reaching the skin is critical. The doses needed are small, and daily exposures of the face and hands to sun and light for 15 minutes is considered sufficient. The minimum dose requirement was estimated to be equivalent to 55 MED per year (Health Council of the Netherlands, 1986). When too little UVB reaches the skin, deficiencies of vitamin D may occur, resulting in a weakening of the bones. Groups at risk are particularly dark-skinned children in high latitude cities and elderly people living entirely indoors. Supplementation of vitamin D3 in the diet is then recommended. It has (also) been suggested that beneficial effects of UV exposures may occur such as: improvement of cardiopathy and functions, and better microorganism defense.
      One beneficial effect of modest exposure to UVB radiation is the maintenance of the ability of the skin (through sun tanning) to sustain further UV exposures. Loss of this adaptation forms an important component in photodermatosis, skin diseases where the lesions are caused by light. These patients can be treated by regular exposures to UVB. The doses required are in the same range as that needed for the synthesis of vitamin D3.
Instruments for measuring UV

The criteria that I have established for selecting proper instrumentation is as follows:

      1. is not prohibitively expensive 
      2. is not overly complicated and directed towards scientific uses
      3. is not difficult to maintain and calibrate
      4. is not too simplistic so that it will give us a meaningful scale
      5. is not too limited in its scale so that it may not respond to the high ranges about which we are speculating as to occurring
      6. is hardened so that will not be damaged by those high ranges
      7. is not overly delicate so that we can use it in the hazardous situation that we anticipate
      8. ideally the equipment would be either EMP hardened or not EMP sensitive, however there are other solutions for dealing with EMP.
I have found some possible equipment solutions and present them on a separate page.
   
Strategies for combating excessive UV

There come to mind several strategies for combating excessive UV.
 
Timing
First and foremost would be that of timing. Those individuals who have to work outside might try to do so in the twilight periods (before sunrise and after sunset) during the most serious circumstances. They should definitely avoid the midday hours if the situation is serious. The southern hemisphere custom of a midday siesta could certainly be considered everywhere.

Clothing

      The most effective way to protect the skin from UV is to cover it. ...the areas of the body most at risk are the face (and eyes) and neck, the forearms and the backs of the hands. The face can be protected by a shield and this should also provide eye protection. The arms should be covered by clothing with a low UVB transmission; in general materials that are visibly opaque are suitable. Hands can be protected by wearing gloves.
A high protection factor is associated with a tightly woven (not knitted) material. UV is transmitted and scattered through the interstices of the material itself rather than penetrating the fabric. 

Brimmed Hats

      If a brimmed hat is worn, the direct image of the sun on the retina is rare and overhead UV exposure is virtually eliminated. However, while using a hat the lid opens further and ground reflection of UV could become important. On an overcast day, the lids open wider, and although the UVB irradiance is reduced by cloud cover, the actual UVB dose rate to the eye from atmospheric scattering near the horizon may be reduced by a factor of only two (Sliney, 1983). Hence, on a cloudy day the eye may receive a greater UVB dose than on a bright sunny day. However, a heavy overcast may attenuate the UVB sufficiently, that this observation may not be true. As sunglasses are not typically worn on an overcast day, one could argue that the concern over sunglasses increasing total ocular exposure is unimportant. However, sunglasses should have sufficient UV filtration so that ocular exposure does not actually increase when they are worn on a sunny day. The presence of a brimmed hat reduced the face exposure by a factor of at least two and the eye exposure was reduced by a factor of 4 to 5 (Diffey et al., 1979, Roy et al 1988).
Sunglasses

Eye protection is extremely important. Long term effects in the way of eye cancer and blindness can be very detrimental.

      For outdoor workers and the general public, the most hazardous source of UV exposure is the sun. Adequately designed (ski) goggles afford protection against exposure to solar UV at high altitudes and on snow, but for most other exposure conditions, good UV absorbing sunglasses (under normal conditions) are an adequate means of eye protection.
Dark sunglasses are NOT the answer. They can have the OPPOSITE effect that one might suppose. The reason is that if they are not special polarized UV protective their being dark will cause the pupil to open wider and the optic nerve will be exposed to MORE UV. Be WARNED about this.

      If dark lenses are placed over the eyes, the natural aversion to bright light, which leads to the squint reflex (that greatly lowers retinal UV or exposure to the eye), would be disabled. This may appear to be an unusual way to consider the comfort that shaded lenses provide. However, poor sunglasses may actually lead to a higher UV exposure (Sliney, 1983). Face shields, goggles or safety spectacles which absorb UV should be worn where there is a potential eye hazard.
Squinting
      People seldom look directly at the sun when it is overhead and very hazardous to view. It is not very hazardous to view when the sun is low in the sky and falls within the normal field-of-view. When the sun is more than 10° above the horizon, the natural tendency is to partially close the eyelids or squint (called squint reflex), thus shielding the retina from direct exposure. These factors reduce the exposure to the cornea to a maximum of about 5% of that falling upon the exposed top of head (Sliney, 1986). If the squint and other behavioural factors are not considered, the dose to the eyelid would be approximately 20% of the dose falling on a horizontal surface. When looking at snow, UV is reflected directly into the eye; hence, the traditional eye protector of the Inuit or Eskimo, the slit, in whalebone or in a seal-skin mask, provided geometrical rather than spectral protection against UV exposure (Hedblom, 1961). The lack of protection above and to the sides of sunglasses is a serious shortcoming. However, to obtain a quantitative idea of this component of exposure to the eye, measurements were made using a simulated ocular geometry in sunlight (Sliney, 1986). The human eye received 10 to 25 % of the UV dose when wearing glasses with lenses opaque to UV compared to no lens in the glasses. Therefore, unless goggles with side-shields are used, UV transmission factors in lenses much less than 2-5 % do not provide the eye protection suggested by the transmission factor (Sliney, 1986).
Nutrition
      Nutrition can provide the body with essential antioxidants and these molecules are distributed throughout the body. At the cellular level, they enter a number of endogenous photoprotective systems to control photochemical processes (Roberts et al., 1991). Quenchers which can negate specific reactive intermediates may be important as a defence mechanism against UV insult to the eye. Glutathione, due to the low energy of the SH (thiol) bond (65 kcal) is an efficient free-radical scavenger and singlet oxygen quencher. Ascorbic acid quenches free radical and superoxide reactions. alpha-Tocopherol quenches both singlet oxygen and free radicals. There are also various antioxidant enzymes present in the eye. Exogenous scavengers and quenchers may be able to prevent UV damage by interrupting transient intermediates which cause ocular damage. An approach is to increase the known endogenous quenchers, (antioxidants) ascorbic acid, alpha-tocopherol and ß-carotene in the diet (Roberts et al., 1991).
Sun Screens

Surprisingly, while millions of dollars are spent marketing sunscreens and the pharmaceutical companies, medical associations, and weather bureaus all combine to promote them, the scientific studies themselves indicate that they are contra-indicated. That is to say - you should not use them. The reason is - UVB darkens the upper layers of the skin, and the creams and lotions enhance this darkening so that one does not as readily burn if they develop a tan (and some tanning is beneficial for that reason). HOWEVER, the tan does not prevent the UVA from penetrating through to the deeper cells where the DNA is affected and the detrimental causes of cancer occur. For this reason sunlamps and sun tanning are generally non-beneficial.

      Here the protection factor is an estimate of the protection afforded against biologically effective solar radiation. A statistically significant positive association of "often or very often" use of sun protection agents with melanoma (relative risk 1.8, 95% confidence interval 1.5-3.8) was found by Beitner et al. (1990). In their cohort study of basal cell carcinoma in US nurses, Hunter et al. (1990) found a higher risk in those who spent 8+ hours per week outside and used sunscreen than in those who spent the same time outside but did not use sunscreen. Sunscreens effectively block solar UVB. UVB is the normal stimulus for accommodation of the skin such as thickening and increased pigmentation. Sunscreens suppress normal warnings of overexposure such as erythema and sunburn and allow excessive exposure to wavelengths of sunlight they do not block. Due to lack of these natural signs sunscreens create a false sense of security and individuals tend to stay in sun longer. In view of these behavioural changes which increases individuals UVA exposure it has been suggested that, because of the rising incidence of melanoma, UVA may be associated with its occurrence (Garland et al., 1992). While a recent study (Setlow et al., 1993) in fish reported melanoma induction by UVA, the role of UVA in the causation of human malignant melanoma has yet to be established.
      While further studies are still needed to clarify concerns raised about the ingredients and protectiveness of sunscreens, broad spectrum sunscreens which absorb both UVA and UVB with an SPF of at least 15 are still recommended as an effective means of personal protection against UV exposure.
So - you can decide for yourself. 

CONCLUSIONS

Most of the descriptions of Nuclear Winter and the concomitant effects of intensive UV come from non-governmental sources which we might well also characterize as anti-survivalist. They hold out little hope, and give little encouragement for survival.

As with dozens of other papers that I have provided on the subject of nuclear survival I do not doubt but that this one will also be subjected to ridicule. I find it strange that the government can take down the nuclear survival shelter signs, scrap the civil defense radiation detection equipment, ridicule the researchers and teachers of survivalist techniques - such as myself - and still spend billions upon billions in developing nuclear weapons and their means of delivery.
But that is the way that it is.

at No comments:
Labels: , ,
Subscribe to: Posts (Atom)

The countdown is winding down

As we can see on the blog, the countdown for the #3DD has not yet arrived. Still, it is my firm belief that the #ThreeDaysOfDarkness will co...