Exploratory study on the body distribution of skin color, pigmentation and, degree of tan in Central European Caucasian Women.

It is well known that skin color varies by body site and with season. However, little quantitative data on the topography of skin color and pigmentation are available. Therefore, exploratory cutaneous colorimetric measurements in 20 in central European Caucasian women aged 20 to 60 years have been made at 18 body sites. Tri-stimulus L*a*b*-values, hue, and chroma are considered to describe skin color. Based on the "Individual Typology Angle", the "Degree of Tan" was introduced to quantify the difference between constitutive and facultative pigmentation. Measurements were done in late winter and early summer to estimate potential changes by solar ultraviolet radiation. These measurements made evident that skin color obviously differs across the body in late winter. Even nearby body sites can be recognized as differently colored. A remaining degree of tan was found at permanent and intermittent exposed body sites. The remaining tan was not most pronounced at the permanently exposed sites but on the intermediate ones like the shoulder. In early summer, the degree of tan has most developed at the hands, arms, and instep, followed by the face. This study showed that besides basic differences between body sites in winter, accumulation, and degradation of tan also vary between body sites.

Modeling acute and cumulative erythemal sun exposure on vulnerable body sites during beach vacations utilizing behavior-encoded 3D body models.

Vacationers in a high-solar-intensity beach setting put themselves at risk of ultraviolet radiation (UV) over-exposure that can lead to acute and chronic health consequences including erythema, photoaging, and skin cancer. There is a current gap in existing dosimetry work on capturing detailed time-resolved anatomical distributions of UV exposure in the beach vacation setting. In this study, a radiative transfer model of the solar conditions of Tampa Bay, St. Petersburg, Florida, USA (27.8°N, 82.8°W) is combined with an in silico three-dimensional body model and data on typical beach vacation behaviors to calculate acute and cumulative body-site-specific UV exposure risk during a beach vacation. The resulting cumulative UV exposure calculated for a typical mix of clothing choices, settings, and activities during a week-long (7-day) beach vacation is 172.2 standard erythemal doses (SED) at the forearm, which is comparable with the average total annual UV exposure of European and North American residents and consistent with existing dosimetry studies. This model further estimates that vacationers choosing to spend a full day exclusively in the beach or pool setting can experience UV exposure in excess of 50 SED a day at multiple body sites. Such exposure indicates that significant sun protective measures would be required to prevent sunburn across all skin types in this setting. This work clarifies the significant role that beach vacations play in UV exposure and corresponding acute and cumulative health risks and highlights the importance of behavioral choices (including clothing, activity and photoprotection) as crucial factors in differentiating personal solar exposure risks.

Possibilities to estimate the personal UV radiation exposure from ambient UV radiation measurements.

People are exposed to solar ultraviolet radiation (UVR) throughout their entire lives. Exposure to UVR is vital but also poses serious risks. The quantification of human UVR exposure is a complex issue. Personal UVR exposure is related to ambient UVR as well as to a variety of factors such as the orientation of the exposed anatomical site with respect to the sun and the duration of exposure. This is mainly determined by personal behaviour. A variety of efforts have been made in the past to measure or model the personal UVR exposure of people and often personal UVR exposure has been expressed as the percentage of ambient UVR. On the other hand, ambient UVR is being monitored at a variety of places and measurements are available even online. This suggests that both the knowledge of personal UVR exposure and measurements of ambient UVR is required. In this paper, a summary on the different methods, which use ambient UVR measurements to estimate personal UVR exposure of people, as well as a few examples, are given. Advantages and disadvantages will be discussed as well as possibilities and limitations. This also includes an overview of appropriate terminology, units and basic statistic parameters to describe personal UVR exposure.

Correction: A library of action spectra for erythema and pigmentation.

Correction for 'A library of action spectra for erythema and pigmentation' by Alois W. Schmalwieser et al., Photochem. Photobiol. Sci., 2012, 11, 251-268, DOI: .

UV Index monitoring in Europe.

The UV Index was established more than 20 years ago as a tool for sun protection and health care. Shortly after its introduction, UV Index monitoring started in several countries either by newly acquired instruments or by converting measurements from existing instruments into the UV Index. The number of stations and networks has increased over the years. Currently, 160 stations in 25 European countries deliver online values to the public via the Internet. In this paper an overview of these UV Index monitoring sites in Europe is given. The overview includes instruments as well as quality assurance and quality control procedures. Furthermore, some examples are given about how UV Index values are presented to the public. Through these efforts, 57% of the European population is supplied with high quality information, enabling them to adapt behaviour. Although health care, including skin cancer prevention, is cost-effective, a proportion of the European population still doesn't have access to UV Index information.

Exposed Body Surface Area-A Determinate for UV Radiant Energy in Human UV Exposure Studies.

Solar ultraviolet (UV) exposure of people and related health risk is mainly examined by estimating the received UV radiant exposure. However, for several effects such as DNA damage, vitamin D photosynthesis or the probability of developing skin cancer, UV radiant energy is important and with that the size of exposed skin area. There is also a complex interaction between body shape and behavior like sun exposure habits, so that careful analysis is necessary when estimating health effects from UV exposure. In this paper, knowledge on body shape and methods of calculating the total body surface area (BSA) are summarized. BSA depends mainly on the height and weight of a person as well as on gender, ethnicity and body shape. BSA and body shape differ significantly between different populations and both change during life. This paper proposes formulas for BSA that consider height, weight, gender, ethnicity and body shape. As the exposed BSA depends on clothing, finally an approach is presented which aims to calculate the size of body parts released by real garments. In summary, this paper will enable future researchers to quantify the exposed BSA by best matching their study population and consequently investigate risks caused by solar UV exposure.

Is sunscreen alone effective at preventing sunburn on a high-solar beach vacation: A modeling study?

Beach holidays in areas of strong sunlight are popular and sunscreen is often the primary means of photoprotection favored by many people. The object of this study was to estimate how effective sunscreen is in preventing sunburn under high ultraviolet (UV) levels. We used a computational model to determine how the quantity, frequency, substantivity, and labeled SPF of applied sunscreens impact on the predicted erythemal response in unacclimatized skin over the course of a 7-day holiday in a high-solar environment. Our results indicated that sunscreen on its own may be insufficient to prevent sunburn in white skin on a sun-seeking holiday that combines prolonged exposure with high UV levels. Nevertheless, sunscreens have a valuable role to play on a beach holiday especially if an SPF30 or higher is chosen, the product is applied liberally and uniformly, application is started early into the sun exposure period and repeated at 2-hourly intervals throughout the day, and the product binds well to the skin. The main limitation of our investigation is that it is not an observational study but rather a computational model and while all models are wrong, some, including this one, are useful.

A library of action spectra for erythema and pigmentation.

The first action spectra for erythema and delayed pigmentation in human skin were determined 90 years ago by Karl Hausser and Wilhelm Vahle in Germany, and since then a number of studies have been undertaken to redefine these action spectra. In this paper we give an overview of the action spectra for erythema and pigmentation that have been published during this 90-yr period, as well as indicating their uncertainties and shortcomings.

Potential of Solar UV Radiation for Inactivation of Coronaviridae Family Estimated from Satellite Data.

The pandemic COVID-19 disease affects people dramatically overall the globe by illness and death. Several strategies are applied to restrict the spread of this disease such as lockdown, adequate social distance in different activities, hand disinfection and the use of masks. Potential hazard outdoors comes from released viruses, which may remain in the air for a while and settle down afterward and contaminating surfaces. Solar ultraviolet radiation (UVR) is known to act as a natural environmental virucide. The virucidal effectivity of UVR depends on a first order on the sensitivity of the virus against UVR as well as on the amount of incoming UVR. Here, we present estimates of the potential of solar UVR in inactivating SARS-CoV-2 in the environment. This is done by combining DNA-damaging surface solar UVR retrieved by satellites and the available information on fluence for inactivation of Coronaviridae. Our results show that solar UVR has a high potential to inactivate these viruses, but the degree depends strongly on location and season. In the subtropics (Sao Paulo, 23.5°S), the daily survival fraction is lower than 10-4 during the whole year, while close at norther latitudes (Reykjavik, 64°N), such a reduction can be found in June and July only.

Sunscreens and occupation: the Austrian experience.

Since the nineteen fifties the attitude of the fair-skinned world population towards the sun has changed dramatically. Tanned skin, which before was regarded as the stigma of the underprivileged working classes, became fashionable and desirable. The science of photoprotection primarily focuses on ultraviolet exposure during leisure time activities, whereas ultraviolet radiation is still underestimated as a risk factor for UV-induced skin and eye problems. The actual discussion on the registration of UV-induced skin tumours as occupational diseases, however, has drawn more attention to this important issue. Ambient radiation, the working process itself and the photoprotective behaviour of an outdoor worker are the main factors which influence the actual UV exposure. However, the total risk for the development of actinic damage results from the interaction of both the occupational and the leisure time exposure. It is evident that there is a high need for photoprotective measures for outdoor workers. Topical sunscreens as a part of a comprehensive UV protection strategy for outdoor workers have to fulfil special requirements: reasonable price, high water resistance, non-sticky appearance. At present only a few products are available which meet these criteria. This is the reason why sunscreens are not so well accepted by outdoor workers. Great efforts have to be undertaken to improve sunscreen formulations and to convince people to apply them correctly and regularly.

Sensitivity of erythemally effective UV irradiance and daily exposure to temporal variability in total ozone.

The provision of information to the public about current levels of the erythemally effective UV radiation is an important issue in health care. The quality of promoted values is therefore of special importance. The atmospheric parameter which affects the erythemally effective UV radiation under clear sky most is the total ozone content of the atmosphere. In this paper we examined the sensitivity of the erythemally effective irradiance and daily radiant exposure to the temporal variability of total ozone on time scales from 1 to 15 days. The results show that the sensitivity is highest for the first 24 h. Larger time scales do not exhibit a similar influence. Total ozone measurements of the previous day may already cause uncertainties higher than 0.5 UV index (UVI) independent of the geolocation. For comparison, a temporal persistence of 15 days may cause uncertainties of 1.2 UVI at 50 degrees N, 1 UVI at 30 degrees S and less than 1 UVI at the equator. The results of this study allow finding the necessary temporal resolution of total ozone values when a certain accuracy for the UVI or for the purpose of sun protection is required. The results are compared with those of two preceding studies where we quantified the influence of measurement uncertainties and spatial total ozone variability to the erythemally effective irradiance at noon and to the daily dose. We conclude that temporal variability of total ozone is the most critical issue, but also measurement uncertainties do have a noticeable influence on the erythemally effective radiation.

Influence of Air Temperature on the UV Exposure of Different Body Sites Due to Clothing of Young Women During Daily Errands.

Clothing is one of the main influencing factors for personal ultraviolet radiation (UVR) exposure. Despite that, little attention was put on this topic till now. In this study, the clothing habits of young females have been investigated in dependence of meteorological conditions. Observations were made from spring to autumn during daylight in the urban region of Vienna, Austria. For this, a scheme dividing the body into six different sections was developed as well as a coding scale that corresponds to the different garments and indicates the body sites that are exposed. It was found that air temperature is the dominating factor for exposure. With increasing temperature, the first area of the body to be exposed to solar UVR is, aside from face and hands, the décolleté, followed by nape, ankles, instep and forearms. Observations further indicate that the frequency of people's being outdoors decreases significantly at temperatures higher than 30°C. This paper provides detailed frequency distributions of uncovered body sites in dependence of temperature. These can be used together with measurements of temperature and UVR to calculate the relative exposure at any time and at many locations, and could help to explain the body distribution of UVR caused skin alterations.

The Austrian UVA-Network.

The ultraviolet-A (UVA) part of the solar spectrum at the Earth's surface is an essential environmental factor but continuous long-time monitoring of UVA radiation is rarely done. In Austria, three existing stations of the UV monitoring network have been upgraded with UVA broadband instruments. At each station, one instrument measures global UVA irradiance and-in parallel-a second instrument measures diffuse irradiance. Recent and past measurements are available via a web page. This paper describes the used instruments, calibration and quality assurance and control procedures. Global and diffuse UVA measurements during a period of up to 5 years are presented. Data indicate clear annual courses and an increase of UVA with altitude by 8-9% per 1000 m. In the first half of the year, UVA radiation is higher than in the second half, due to less cloudiness. In Vienna (153 m asl), the mean daily global UVA radiant exposure in summer is almost as high as at Mt. Gerlitzen (1540 m asl), equalizing the altitude effect, due to less cloudiness. However, in winter, the UVA radiant exposure at Mt. Gerlitzen is double as high, as in Vienna.

Sensitivity of UV erythemally effective irradiance and daily dose to spatial variability in total ozone.

The total ozone column (TOC) is the most significant quantity for estimating the erythemally effective UV radiation under clear sky conditions. Uncertainties in TOC measurements and a limited spatial and temporal resolution therefore influence the quality of calculated erythemally effective radiation. The UV Index, the internationally accepted measure of the erythemally effective radiation, is used in public and the media to inform about current levels of UV radiation and builds the base for sun protection. Thus, the accuracy of the promoted values is essential. While in a preceding study we estimated the influence of measurement uncertainties, in this study we analyze the influence of spatial gaps and variability of TOC to the erythemally effective irradiance at noon and to the daily dose. The results allow defining the necessary spatial resolution of TOC values when a certain accuracy for the UV Index or for the purpose of sun protection is required. In case of the erythemally effective irradiance this study reveals that spatial gaps in TOC or the assumption of spatial invariability causes similar uncertainties independent of the geographic location. At higher latitudes the higher spatial variability of TOC counteracts the lower level of irradiance. For the daily dose gaps in TOC have an even higher impact at higher latitudes.

Review on Nonoccupational Personal Solar UV Exposure Measurements.

Solar ultraviolet (UV) radiation follows people during their whole life. Exposure to UV radiation is vital but holds serious risks, too. The quantification of human UV exposure is a complex issue. UV exposure is directly related to incoming UV radiation as well as to a variety of factors such as the orientation of the exposed anatomical site with respect to the sun and the duration of exposure. The use of badge-sensors allows assessing the UV exposure of differently oriented body sites. Such UV devices have been available for over 40 years, and a variety of measuring campaigns have been undertaken since then. This study provides an overview of those studies which reported measurements of the personal UV exposure (PE) during outdoor activities of people not related to their occupation. This overview is given chronologically to show the progress of knowledge in this research and is given with respect to different activities. Special focus is put on the ratio of personal exposure to ambient UV radiation. This ratio, when given as a function of solar elevation, allows estimating PE at any other location or date if ambient UV radiation is known.

Diffuse Reflectance Spectroscopy as a Reliable Means of Comparing Ultraviolet Radiation-induced Erythema in Extreme Skin Colors.

Erythema is widely considered an indicator of skin cancer susceptibility, but assessments are challenging in black skin because melanin can mask erythema under traditional visual and advanced objective Commission Internationale de l'Eclairage (CIE) L*a*b* assessments. Using spectral measurements (400-700 nm) from a spectrophotometer, an algorithm was developed to measure erythema in white Caucasians (n = 9) and black West Africans (n = 11) 19-24 h postsolar simulated radiation (SSR) exposures to the volar forearm. The derived spectrum achieved showed a strong maximum peak for hemoglobin at 580 nm and a linear slope between 650 and 700 nm for melanin absorption, as reported by other authors. Absorption by hemoglobin at 580 nm was used as a proxy for erythema, and melanin was quantified between 650 and 700 nm. Our algorithm corrected the erythema measurements for stray specular (mirror-like) reflection and the melanin-masking effect. A linear relationship between SSR exposure and erythema was evident (p < 0.0001 for white and black skin), and white skin is 8.4 times more responsive to SSR compared to black skin. The prediction of ultraviolet radiation sensitivity is vital in both clinical and investigative dermatology especially in the determination of starting phototherapy doses. Our methodology allows for the accurate assessment of erythema independent of constitutive pigmentation.

Sensitivity of erythemally effective UV irradiance and daily exposure to uncertainties in measured total ozone.

In this study the sensitivity of the erythemally effective radiation to uncertainties in operationally measured total ozone content of the atmosphere (TOC) was estimated. For this, daily operational TOC measurements from different instruments were applied covering the period from 1997 to 1999. Measurements were gained from space by Earth Probe Satellite, Earth Remote Sensing satellite/Global Ozone Monitoring Experiment and Operational Vertical Sounder and from the ground by Dobson and Brewer spectrophotometers for the locations of Hradec Kralove (Czech Republic, 50 degrees N), Nairobi (Kenya, 1 degrees S) and Springbok (Republic of South Africa, 30 degrees S). The values were used as input parameter to model calculations of erythemally effective irradiance and daily radiant exposure. The differences due to the use of TOC from different sources were analyzed with respect to the Ultraviolet Index (UVI). The UVI was introduced as a tool for sun protection and health care. Therefore, it is of special importance to know the restriction of accuracy. As a tool of health care, the maximum uncertainties are of interest and are described in using the 95%-percentile and the maximum differences. This study shows that differences, i.e. uncertainties (95%-percentile) are in the order of 1 UVI. Independently on the location, however, extreme differences may overstep 3 UVI. For the daily dose the 95%-percentile is around 7.5 UVI hours (UVIh) but differences higher than 20 UVIh were also found.

Global forecast model to predict the daily dose of the solar erythemally effective UV radiation.

A worldwide forecast of the erythemally effective ultraviolet (UV) radiation is presented. The forecast was established to inform the public about the expected amount of erythemally effective UV radiation for the next day. Besides the irradiance, the daily dose is forecasted to enable people to choose the appropriate sun protection tools. Following the UV Index as the measure of global erythemally effective irradiance, the daily dose is expressed in units of UV Index hours. In this study, we have validated the model and the forecast against measurements from broadband UV radiometers of the Robertson-Berger type. The measurements were made at four continents ranging from the northern polar circle (67.4 degrees N) to the Antarctic coast (61.1 degrees S). As additional quality criteria the frequency of underestimation was taken into account because the forecast is a tool of radiation protection and made to avoid overexposure. A value closer than one minimal erythemal dose for the most sensitive skin type 1 to the observed value was counted as hit and greater deviations as underestimation or overestimation. The Austrian forecast model underestimates the daily dose in 3.7% of all cases, whereas 1.7% results from the model and 2.0% from the assumed total ozone content. The hit rate could be found in the order of 40%.

Sun behaviour and personal UVR exposure among Europeans on short term holidays.

Solar ultraviolet radiation (UVR) is known to be the main cause of skin cancer, the incidence of which is rising with national differences across Europe. With this observation study we aimed to determine the impact of nationality on sun behaviour and personal UVR exposure on sun and ski holidays. 25 Danish and 20 Spanish sun-seekers were observed during a sun holiday in Spain, and 26 Danish and 27 Austrian skiers were observed during a ski holiday in Austria. The participants recorded their location and clothing in diaries. Personal time-logged UVR data were recorded as standard erythema doses (SEDs) by an electronic UVR dosimeter worn on the wrist. Danish sun-seekers were outdoors for significantly longer, received significant higher percentages of ambient UVR, and received greater accumulated UVR doses than Spanish sun-seekers. Danish skiers were also outdoors for significantly longer than Austrian skiers, but the behaviour of the Danish skiers did not result in significantly greater accumulated UVR doses. Both Danish and Spanish sun-seekers and Danish and Austrian skiers received substantial UVR doses. The behaviour's influence on the UVR doses received by the Danish participants may indicate an explanation of the higher skin cancer incidence among Scandinavians compared with other European populations.

Evaluation of the goodness of fit of solar simulated radiation to a reference solar spectrum for photobiological experiments.

There is a great need for photochemical and photobiological experiments to mimic the spectral distribution of solar ultraviolet radiation by artificial ultraviolet sources. The spectral distribution of various ultraviolet sources were compared with a reference solar spectrum which represents a realistic maximum solar spectrum under cloudless sky. Various methods to compare the artificial sources with the COLIPA solar reference spectrum were presented. Beside a graphical method which is based on the Lorenz curve also integral indices were used to characterize the deviations from the solar spectrum. Following parameters should be used to characterize an artificial source: (1) total output of the biologically effective irradiance, (2) maximum deviation of the cumulative relative spectral irradiance of the biologically effective solar simulated radiation, (3) spectral distribution of the difference of the cumulative relative spectral irradiance of the biologically effective solar simulated radiation, and (4) the index of the goodness of the spectral fit. Further on upper and lower limit values are suggested to improve the quality of the spectral fit of solar simulated radiation and the irradiance maximum should be limited to the range in which dose reciprocity is known to be conserved.