Ultraviolet (UV) radiation is the most energetic part of optical radiation. It presents the transition from non-ionising radiation to ionising radiation in the electromagnetic spectrum.

UV radiation is divided into three wave length ranges: UV-C radiation (100 – 280 nm), UV-B radiation (280 – 315 nm) and UV-A radiation (315 – 400 nm). The shorter the wavelength, the more energetic is the radiation and the more harmful it is for us.

The most important natural source of UV radiation is the sun. The fraction of UV-radiation from the sun which reaches the ground varies substantially depending on the position of the sun (latitude, time of day and time of year), the overall ozone content of the absorbing layers and the sky cover. The ozone in the high atmosphere (stratosphere) retains the high-energetic UV-C radiation completely and parts of UV-B radiation. Thus only parts of UV-B radiation and almost the complete UV-A radiation reach the surface of the earth.

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UV radiation mainly affects the human skin and the eyes and has an impact on the immune system. UV effects can be acute (immediate) or chronic occurring only after longer periods of exposure to UV radiation. Most UV effects are detrimental to health.

Only if you enjoy the sun moderately, the sunlight will improve your health. Your body needs only small amounts of UV-B radiation to generate vitamin D.

In the course of the human evolution the skin has formed different protection mechanisms: tanning of the skin stimulated by UV radiation (i.e. melanin synthesis) and thickening of the top skin layer, the horny layer, which occurs after the skin has been exposed to UV radiation and which is called hyperkeratosis.

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Hyperkeratosis does not occur in small children so that children under the age of two should not be exposed to direct solar radiation at all. Hyperkeratosis forms slowly in the course of childhood under the influence of UV radiation. So even older children should be carefully protected when exposed to sunlight. They should wear clothes, a sunhat and sun glasses and should use a sunscreen with a high protection factor (at least SPF 15). Please note that snow, sand and water reflect UV radiation and that only thick closed cloud cover totally protects you from UV radiation whereas broken clouds can possibly even intensify UV radiation. When doing winter sports or spending your holidays at the seaside you should therefore be particularly careful.

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Among the acute effects sunburn should be mentioned first. It is a visible inflammation of the skin, which is caused by UV radiation and which occurs around three to six hours after its exposure to UV radiation. The amount of UV needed to develop a sunburn depends on the skin type: fair-skinned persons with reddish or blond hair are considerably more sensitive than dark-haired, brunette people.

Further acute effects of UV radiation are hypersensitivity reactions or allergic reactions of the skin. They occur most frequently in people that have applied certain substances such as pharmaceuticals, cosmetics or herbal substances and are exposed to UV-A radiation.

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The most dangerous chronic effect provoked by UV radiation is skin cancer. Dermatologists believe that the increasing occurrence of different types of skin cancer mainly results from the change in recreational behaviour, e.g. frequent sunbathing, holidays in the south, use of solaria etc. Around 120,000 new cases of skin cancer are observed each year in Germany – and the number is constantly increasing. The rate of newly diagnosed malignant melanoma has tripled over the last 20 years.

Basal cell carcinoma and squamous cell carcinoma occur most frequently on those parts of the skin which are particularly exposed to sunlight. It is proven that the risk for these types of skin cancer does increase with the total UV exposure in a person’s lifetime (“Your skin remembers every exposure.”) The malignant melanoma, however, often occurs on parts of the skin which are not constantly exposed to the sun. There is scientific evidence, that the number of  sunburns experienced especially in young ages play an important role in the development of malignant melanoma.

Recognised early, skin cancer can be cured in most cases. It is therefore important to regularly use the skin cancer screening programme offered by the German health system. In addition, it is wise to prevent skin cancer in the first place through a responsible behaviour in the sun.

If you wish to have a tanned skin, please do not forget that frequent and intensive exposure to UV radiation may affect the immune system of your body. UV also accelerates the premature ageing of your skin. In particular UV-A radiation penetrates deeply into the skin, it makes the skin dry and destroys the connective tissue. It reduces the skin’s elasticity so that the skin tends to wrinkle and to appear leathery.

Please do not forget that your eyes need particular protection in the sun as well, since UV radiation may lead to eye cataract and retina damage in the long run.

Thus, if you wish to enjoy the sun, please note our recommendations for your protection against UV radiation (in German).

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The UV index (UVI) describes the daily peak value of sunburn-effective UV radiation on the ground. The higher the UVI the higher is the UV exposure and the more likely it is to get sunburn. In Germany, the UV index reaches peak values of around 7 on sunny days in the middle of summer, sometimes even higher. Please do not forget that only thick grey clouds totally protect you from UV radiation whereas broken clouds can possibly even intensify UV radiation.

For more information on the UV index (in German) please click here.

The time you can spend in the sun without getting sunburn depends on the UVI, your skin type and the level of pre-tanning. Persons with very sensitive skin and reddish hair get sunburn earlier, brunette persons, however, can stay in the sun unprotected for longer periods of time. Already at a UVI value of 5, blonde, fair-skinned people can get sunburn after half an hour at noon, if they are not accustomed to UV radiation and do not protect themselves against it. At a UVI value of 7 this is already the case after 25 minutes, at a UVI value of 8 after about 20 minutes. In the early morning and in the evening you may spend longer periods of time in the sun unprotected.

Even if you do not get sunburn, the UV radiation may harm your skin so that it is generally recommended to protect yourself against UV radiation not only to prevent sunburn.

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Since 1993, the Federal Office for Radiation Protection (BfS) and the Federal Environment Agency (UBA) monitor the UV radiation from the sun reaching the ground in cooperation with associated institutions. They operate a UV measuring network at various sites in Germany. The network also registers changes, that are associated with the elevation of the sun (e.g. between summer and winter or between places in the north or in the south of Germany). The potential impact from the depletion of the ozone layer and the cloud cover are also taken into account. Since the wavelength of the UV radiation is important for their potential health effects, the UV radiation measured is broken down to its different wavelengths. For more information on the UV index (in German) please click here.

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Simple rules help to reduce the risk of getting sunburn significantly. A moderate exposure to solar radiation is the most important advice. BfS recommends to protect yourself against sunburn and other detrimental effects.

Solar radiation is strongest in the hours around midday, so it is best to spend the time between 11 am and 3 pm in the shade. Clothes, sun hat and sun glasses offer the best protection. A sunscreen providing protection both in the UV-A and in the UV-B range should be applied to the uncovered parts of your body. The sun protection factor (SPF) should at least be 15 – blond, fair-skinned persons and people spending their holidays in the south should even use a higher protection factor.

It is recommended to apply the sunscreen generously to the skin around 30 minutes before sunbathing. Cosmetics such as perfume, deodorant and aftershave should not be used at all for a sunbath since the skin may react sensitively to these substances in connection with UV radiation and may change colour permanently.

Small children up to the age of two should not be exposed to direct solar radiation at all, since their skin does not provide protection mechanisms so that UV radiation is particularly harmful to them. For older children the general rules (see above) apply.

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Especially in winter tanning facilities advertise intensively by praising the allegedly soothing effect of a sunbath and, of course, by promoting tanned skin. Potential health risks from UV radiation in solaria are frequently not mentioned at all. It’s a fact, however, that tanning in solaria may be as harmful to the skin as tanning in the sun. Exposure to UV rays in a solarium may cause both acute and chronic effects.

The radiation sources used in tanning devices produce both UV-A and the more energetic UV-B radiation. The exact composition of the UV rays depends on the type of lamps and the filters. If the fraction of UV-B radiation is rather low, as it usually is in solaria, the risk of getting sunburn is reduced, but only small amounts of melanin are produced, which is responsible for the human skin colour and the lasting tanning of the skin. Tanning through UV-A radiation occurs very soon but it disappears quickly as well. Furthermore, hyperkeratosis i.e. the protection mechanism of the skin develops only through the effect of UV-B radiation. It is therefore questionable if “pre-tanning” in a solarium helps to protect the skin in the sun, as it is frequently claimed.

UV-A radiation penetrates more deeply into the skin and is therefore to a large extent responsible for premature ageing of the skin, which means that the skin will wrinkle and appear leathery. Intensive exposure to UV-B radiation may induce sunburn. If the skin is sensitised through certain chemicals, UV-A radiation may induce sunburn, too. The artificial UV radiation in a solarium is harmful to the eyes so that it is important to wear appropriate UV protection sun glasses while using a sunbed.

The UV radiation used in solaria affects the genome of the skin cells in the same way as solar radiation. This holds true for both UV-B and UV-A radiation. Sunbathing in solaria therefore increases the skin cancer risk, which has been shown in epidemiological studies. The exact increase of the risk depends on the number of solarium visits as well as the time and intensity of exposure during each visit.

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Children and young people under the age of 18;

Persons with a fair, sensitive skin or a large number of moles;

Persons who had severe sunburns when they were young;

Persons with a family history of skin cancer;

Persons who are currently ill;

Persons suffering of skin cancer or who had skin cancer in the past.

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BfS recommends to observe the following rules: Try to avoid self-service solaria since a qualified, personal consultation with trained solarium staff is absolutely necessary. Such consultation must cover information about health risks from UV radiation, determination of your skin type and an individual schedule fixing the number and intensity of each sunbath according to your skin type. Potential intolerance reactions due to the use of certain pharmaceuticals or cosmetics should be mentioned, too. Persons with an increased risk to UV radiation (cf Question 10: “Who should not use a sunbed at all?”) must be excluded from the use of the solarium. The staff must hand out UV protection glasses which comply with the relevant safety regulations. It is absolutely necessary to wear these glasses in order to avoid damage to your eyes.

Avoid sunburn under any circumstances. To this end, it is essential that the maximum exposure times for your skin type are not exceeded. The German Radiation Protection Commission (SSK) recommends not to take more than 50 sunbaths per year – counting both sunbaths in the solarium and those in the sun. A sunbath meaning in this context exposure of large parts of the body to UV radiation.

Pre-tanning in a solarium (e.g. before going on holidays in the South) cannot be recommended, because this would increase the total dose of UV radiation and thus the risk of long-term effects. In addition, not all sunbeds incite protection mechanisms in the skin.

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The atmospheric ozone largely absorbs the short-wave UV radiation emitted by the sun. If the ozone concentration in the atmosphere is reduced, UV-B radiation on the ground will increase.

It is impossible to forecast the development of the short-wave UV components on the ground since different factors interact in a complex manner. Especially the development of the ozone concentration in the atmosphere is not foreseeable. Please find more details on this topic on the website of the World Meteorological Organisation (WMO).

The Federal Office for Radiation Protection (BfS) has the task to measure the solar UV radiation and to evaluate its effects on people’s health. BfS operates since 1993 a UV measuring network in cooperation with the Federal Environment Agency (UBA) and other associated institutions. Because of the complex interaction of many factors, the ozone impact on ground UV levels can only be detected through long-term measurements over many years. So far, no clear trend in the average UV intensity at ground level has been detected.

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In Germany UV radiation is generally more intensive in summer than in winter due to the higher elevation of the sun. However, a high exposure to UV radiation may also occur in winter since the level of UV exposure also depends on the altitude of a location. Winter sports are often performed in the mountains – the UV levels here are frequently higher than in lower regions. Additionally, there is usually snow in winter sports locations – UV radiation is reflected on it and hits the body as stray light from below and from the side. This explains why people frequently get sunburn in winter sports, in particular in springtime when the sun climbs to a higher position every day. The UV exposure in winter is particularly harmful to your eyes. Acute inflammations of the cornea and the conjunctiva (snow blindness) are possible. In the long term, the UV exposure may lead to an opacity of the eye lens.

Sun protection is therefore absolutely necessary when you are doing winter sports. Please remember to wear high-quality sunglasses also on cloudy days. Besides, all uncovered parts of your body, i.e. face, neck and hands, should be protected with sunscreen. Your sunscreen should have a protection factor between 8 and 15, according to your skin type, and it should protect both from UV-A and UV-B radiation. Children should always use a lotion which is at least SPF 15. In extreme regions, e.g. on a glacier, sun block, lip protection and sun glasses have to be standard equipment. Sun glasses should also provide lateral protection to keep stray light off – ideally choose snow goggles.

Observe these simple rules and enjoy the sun in your winter sports holidays.

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Shortly after halogen lamps had been introduced, BfS performed investigations on the UV exposure caused by these lamps and their potential health effects. In the case of some halogen spotlights, UV exposures were detected up to a distance of 30 to 60 cm which clearly exceeded the guideline values recommended by the International Commission on Non-Ionizing Radiation Protection (ICNIRP). Meanwhile, manufacturers have started using special glass materials in the production of halogen spotlights which filter the harmful UV radiation or they place a UV filter in front of the lamp. Please make sure that the halogen lamps you buy have a UV filter. This is particularly important for lamps used near your body, i.e. desk lamps or reading lamps.

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