Erythemal Ultraviolet Radiation Research Articles

Diffuse UV erythemal radiation experimental values

Measurements of diffuse UV erythemal radiation (UVER) using a shadowband have been corrected using the models proposed by Drummond (1956), LeBaron et al. (1990), and Batlles et al. (1995). Two different methods were used to validate these models: intercomparison with an Optronic OL754 spectroradiometer and comparison with the values simulated by two radiative transfer codes, SMARTS and SBDART. For this comparison only clear days have been used. The corrected experimental values were analyzed in order to study the average values of the diffuse UVER fraction in relation to the clearness index kt. These varied between 62%, for kt close to 0.8, and 93% for kt of 0.2–0.3. Finally, a study of the monthly average and extreme values of the UV Index for diffuse radiation is presented, showing a maximum value of 6 in June.

Testing the applicability of artificial intelligence techniques to the subject of erythemal ultraviolet solar radiation. Part two: An intelligent system based on multi-classifier technique

The problem we address here describes the on-going research effort that takes place to shed light on the applicability of using artificial intelligence techniques to predict the local noon erythemal UV irradiance in the plain areas of Egypt. In light of this fact, we use the bootstrap aggregating ( bagging) algorithm to improve the prediction accuracy reported by a multi-layer perceptron (MLP) network. The results showed that, the overall prediction accuracy for the MLP network was only 80.9%. When bagging algorithm is used, the accuracy reached 94.8%; an improvement of about 13.9% was achieved. These improvements demonstrate the efficiency of the bagging procedure, and may be used as a promising tool at least for the plain areas of Egypt.

Testing the applicability of artificial intelligence techniques to the subject of erythemal ultraviolet solar radiation part one: The applicability of a fuzzy rule based approach

This work presents the applicability of applying a fuzzy logic approach to the calculation of noontime erythemal UV irradiance for the plain areas of Egypt. When different combinations of data sets were examined from the test performance point of view, it was found that 91% of the whole series was estimated within a deviation of less than ±10 mW/m 2, and 9% of these deviations lay within the range of ±15 mW/m 2 to ±25 mW/m 2.

Empirical model for estimating daily erythemal UV radiation in the Central European region

Because of its biological effects, erythemal ultraviolet (UV-ERY) radiation (280-400 nm) is a significant part of solar radiation spectrum. In this study a statistical model for estimating daily UV-ERY radiation values was developed. It is based on ground measurements conducted at eight Austrian stations (from 2000 to 2002). As inputs the model requires daily global radiation, daily extraterrestrial radiation, information about the column of total ozone in the atmosphere and the altitude of a selected station. Subsequently the performance of the model was verified by an independent data set originating from measurements in Austria and Czech Republic stations. The verification showed satisfactory performance of the model: the coefficient of determination (R 2 ) varied from 0.97 to 0.99, the root mean square error (RMSE) varied from 9.3 % to 17.7 % and the mean bias error (MBE) varied from -2.5 % to 2.0 %. In addition, the results of the model at Hradec Kralove station were compared with equivalent UV-ERY data from the Solar Radiation Database (SoDa), which are available on the Internet. After successful verification, the model was implemented within the ArcInfo GIS framework in order to carry out a spatial assessment of a stratospheric ozone reduction episode. The event of July 2005 in the Czech Republic was used as a case study. On 30 July 2005 the total ozone amount dropped 12.5 % below the long-term mean, which led to UV-ERY radiation increment ranging from 214 to 391 J·m -2 ·day -1 .

Ultraviolet Radiation Exposure of Children and Adolescents in Durban, South Africa¶

The solar ultraviolet radiation (UVR) exposure of 30 children and adolescents in three age groups (4–6 years, 7–9 years and 13–14 years) was measured for 1 week in late summer (February–March) in Durban, South Africa, using UVR-sensitive polysulfone film badges (PSFB) attached to the lapel region of the body. The mean and median values for all ages over the study period were 2.0 and 1.2 standard erythemal dose (SED) units, respectively, where 1 SED = 100 J·m−2. Individual PSFB doses were analyzed as a function of age, gender and behavior. No significant statistical differences were found between different age groups; however, there was a statistical difference between males and females, with males generally receiving higher PSFB doses. Subjects completed UVR exposure journals documenting their time outdoors, shade versus sun conditions, nature of their activities, clothing worn and their use of sunscreen for each day of the study. Activity patterns were noted as the most important factor influencing individual UVR dose. Ambient erythemal UVR was measured by a Yankee Environmental Systems UVB pyranometer, and a relationship between ambient UVR and individual UVR dose was derived. On average, subjects received a dose of 4.6% of the total daily erythemal UVR. Based on this factor, the potential dose of an individual over a full annual cycle was estimated. Accordingly, there were 139 days during the year when an individual with skin type I (light skin) would be likely to experience minimal erythema and 97 and 32 days for individuals with skin types II and III, respectively.

Ozone mini‐hole over southwestern Spain during January 2004: Influence over ultraviolet radiation

During the last decades, extremely low total ozone events of small spatial extension, named ozone mini‐hole, have been reported in the Northern Hemisphere. A few ozone mini‐hole episodes, which last only few days, were observed over southwestern Spain during 2004. In this work, these extreme events have been detected using TOMS satellite instrument. Additionally, the UV solar radiation was measured in three cities: Badajoz, Cáceres, and Plasencia. The most intensive episode occurred on 10 January 2004 when total ozone amount values decreased to 189–200 DU. These values represent a decrease greater than 33% with respect to the mean values registered in these cities during 1996–2005. In this paper, firstly we analyse the origin of the ozone mini‐hole episode which is related to two atmospheric dynamics processes. Secondly, the influence of these extreme events on ultraviolet radiation recorded under cloud‐free conditions in southwestern Spain is described. A great increase in UV erythemal radiation measurement was recorded on 10 January 2004, between 43% and 75% with respect to values measured on 10 January 2003 and 10 January 2005.

Daily and annual variations of erythemal ultraviolet radiation in Southwestern Spain

Abstract. The potential danger of ultraviolet (UV) radiation and its increasing levels at the Earth's surface due to ozone depletion have demanded worldwide representative measurements of UV radiation. This study presents four and one-half years of original records of high temporal resolution ultraviolet erythemal radiation (UVER) measured in Badajoz, Spain. Its principal aim is to statistically characterize the UVER magnitude and temporal variations, but also to address the interesting special cases of cloud-free and cloudy skies. In particular, the study reports reliable values of fundamental statistical indices, which can serve as relevant values for comparison with other studies and model results. Moreover, the daily and annual evolution of the main central moments of the distribution function are analyzed and interpreted in terms of the forcing and attenuation sources. The analysis focuses on two different temporal scales: hourly and daily values. Integrated hourly and daily data allow for the study of daily and annual variations of the fundamental statistical indices. All of them exhibit high symmetry with respect to solar noon and to certain dates near summer and winter solstices. The analysis shows the great influence of cloudiness in the distribution of UVER values. Thus, both daily and hourly UVER data present a slightly asymmetrical, left tailed, mesokurtic distribution for all months, except for summer, when the lack of clouds produces a leptokurtic distribution which is skewed to the left.

Protection from Solar Erythemal Ultraviolet Radiation – Simulated Wear and Laboratory Testing

The effect of fabric type, color, fit and wetness on transmission of solar erythemal ultraviolet radiation through garments was investigated using laboratory testing and during simulated wear using a multivariate experimental design. The effect of fabric type, color, and wetness on UVB transmission (280–320 nm) through fabrics was determined under laboratory conditions using a spectrophotometer. Garments were also evaluated under conditions of simulated use in Queensland, Australia using polysulphone dosimeters. Dosimeters, placed against the ‘skin’ at selected sites on the torso and on the adjacent outer-surface of the covering garment, were used to measure solar UVB. During simulated wear the fabric type, fit and color were the main variables affecting UVB transmission through the garments. To optimize protection, dark fabrics with good cover should be constructed into garments with positive design ease, and be selected and worn as loosely-fitting styles that maximize the surface area covered

Investigation of the erythemal ultraviolet trends in the greater Greece area: Implications to human health

Among the most important aspects of the atmospheric pollution problem are the anthropogenic impacts on the stratospheric ozone layer, the related trends of the total ozone content drop and the solar ultraviolet radiation enhancement at the Earth's surface level. This paper presents an investigation of the spatial distribution of the erythemal ultraviolet radiation trends in Greece derived from 1979 to 1991 Nimbus 7 observations. In addition, it examines the adverse impact of the erythemal ultraviolet radiation on human health by employing in‐field measurements deduced from airborne instrumentation.

A Multiple Regression Analysis Between UV Radiation Measurements at Badajoz and Ozone, Reflectivity and Aerosols Estimated by TOMS

This paper analyzes the relationship between ultraviolet erythemal radiation (UVER) measured in Badajoz (Spain) and ozone, cloudiness and aerosols. Initially, the values of transmissivity of UVER are related with three parameters (ozone amount, reflectivity and aerosol index) estimated by the satellite instrument TOMS. The relative importance and dependence of each variable is analyzed by means of a multiple regression analysis with an expression derived from the Lambert-Bouger-Beer law. The results indicate that the aerosol index is not a statistically significant factor for the initial expression. Then, a partial model with only ozone and reflectivity as regressors is proposed and coefficients are obtained using UVER measurements of year 2001. Finally the model is validated comparing its prediction for 2002 with UVER measurements at ground. The agreement between both data sets is reasonably good, suggesting that UVER estimations can be successfully derived from observations of other atmospheric variables, thus providing the basis to obtain spatial distributed maps of UV variations.

Satellite and ground measurements of solar erythemal UV radiation and ozone in Argentina

Solar erythemal UV radiation incident on Argentina from tropical to high latitude regions has been measured with ground-based instruments as well as with the TOMS instrument on board of the NASA Earth-Probe satellite. These data permit validation of the UV index, a measure of solar risk to UV exposure, forecasted daily by CONAE (Argentina National Commission on Space Activities) and the Argentine National Weather Service. Model calculations of this index are also presented. In addition, we analyzed the UV effects from the Antarctic ozone hole passing over the continental part of the country using TOMS data corrected by a factor derived from the intercomparison of TOMS satellite data with those determined with Southern Hemisphere ground-based spectroradiometers. In this way, we obtained a rather comprehensive description of the amount of erythemal UV radiation and consequently of the UV index for the entire country, as well as the ozone total column and profile (the latter one at Buenos Aires). The results presented in this work were determined through collaboration between the following institutions: GSFC/NASA in USA, Institute Pierre Simon Laplace in France, University of Innsbruck in Austria and CEILAP, IFIR, CONAE, SMN, Universities of Rosario and San Luis in Argentina. The need to use erythemal irradiance and ozone results in Argentina, one of the most exposed regions of the Southern Hemisphere to study the effects of ozone depletion and consequently UV detrimental effects, has been partially covered in the framework of this North–South collaboration.

Using the erythemal ultraviolet radiation dose rate at solar noon to approximate the time-integrated daily dose

Using the erythemal ultraviolet radiation dose rate at solar noon to approximate the time-integrated daily dose

Ultraviolet radiation exposure of children and adolescents in Durban, South Africa.

The solar ultraviolet radiation (UVR) exposure of 30 children and adolescents in three age groups (4-6 years, 7-9 years and 13-14 years) was measured for 1 week in late summer (February-March) in Durban, South Africa, using UVR-sensitive polysulfone film badges (PSFB) attached to the lapel region of the body. The mean and median values for all ages over the study period were 2.0 and 1.2 standard erythemal dose (SED) units, respectively, where 1 SED = 100 J x m(-2). Individual PSFB doses were analyzed as a function of age, gender and behavior. No significant statistical differences were found between different age groups; however, there was a statistical difference between males and females, with males generally receiving higher PSFB doses. Subjects completed UVR exposure journals documenting their time outdoors, shade versus sun conditions, nature of their activities, clothing worn and their use of sunscreen for each day of the study. Activity patterns were noted as the most important factor influencing individual UVR dose. Ambient erythemal UVR was measured by a Yankee Environmental Systems UVB pyranometer, and a relationship between ambient UVR and individual UVR dose was derived. On average, subjects received a dose of 4.6% of the total daily erythemal UVR. Based on this factor, the potential dose of an individual over a full annual cycle was estimated. Accordingly, there were 139 days during the year when an individual with skin type I (light skin) would be likely to experience minimal erythema and 97 and 32 days for individuals with skin types II and III, respectively.

Ultraviolet radiation in the Alps: the altitude effect

The Alps are one of the regions where the highest UV levels are measured in Europe. Solar UV radiation increases with altitude mainly due to decreasing amounts of air molecules, ozone, aerosols, and clouds in the atmosphere as well as due to snow covered surfaces. The altitude effect plays an important role in the understanding of the UV radiation field in mountainous terrain. Therefore simultaneous measurements of erythemal UV radiation (broadband) on three different heights were performed in the Alps over more than four years. Under clear-sky conditions, the altitude effect of daily noon-time yearly mean values of direct, diffuse, and global erythemal UV radiation results in 17.4%/1000 m (direct), 8.5%/1000 m (diffuse), and 10.7%/1000 m (global). Seasonal variations of the altitude effect are mainly influenced by changes of solar elevation, albedo values, and turbidity levels during the year. Measured altitude effects are also compared to calculated values obtained by the MODTRAN radiative transmission model.

Influence of ground reflectivity and topography on erythemal UV radiation on inclined planes.

Erythemal UV irradiance incident on a horizontal surface is not always the best way of estimating the real dose received by humans or animals. For this purpose knowledge of the irradiance incident on inclined planes is required. This study presents a physically accurate model for the calculation of erythemal UV on inclined planes. The influence of ground reflectivity and topography on erythemal UV on inclined planes is investigated as a function of solar zenith and azimuth angle. It is shown that including directional reflectivity does not substantially change the incident dose on inclined planes, the maximum deviation being 10%. The incident erythemal UV may, however, be much more influenced by the surrounding topography and by the direct/diffuse partitioning of the irradiance (which is a function of altitude). Maximum increases in erythemal UV of +57%, compared with the incident erythemal UV on a horizontal plane, were found when the sensor faced the sun with a mountain slope to the left and right of it and for very high altitudes.

Experimental values of the UV index during 2000 at two locations in Mediterranean Spain

AbstractDuring the past 2 years automatic measurements of UVB solar irradiance have been made sstematically at ground level at a number of points in Spain. Values for both the ultraviolet erythemal radiation and the ultraviolet index (UVI) have been obtained from these measurements. In this paper we present a first analysis of these values for two locations on the Spanish Mediterranean coast—Valencia and Barcelona—an area where a large part of the summer tourism of the country is concentrated. During the summer the UVI only reached ten on three occasions, though a value of nine was reached repeatedly (both classified as extreme risk by the World Health Organization). It has been shown that, in 90% of cases, the maximum daily value of UVI deviates from the value at solar 12 : 00 by, at most, one unit. The annual accumulated doses are expressed as a function of the minimum erythemal doses corresponding to each of the four usual skin phototypes. Copyright © 2002 Royal Meteorological Society

Variations of erythemal ultraviolet irradiance and dose at Tartu/Tõravere, Estonia

CR Climate Research Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials CR 22:245-253 (2002) - doi:10.3354/cr022245 Variations of erythemal ultraviolet irradiance and dose at Tartu/Tõravere, Estonia K. Eerme*, U. Veismann, R. Koppel Tartu Observatory, 61602 Tõravere, Tartumaa, Estonia *E-mail: kalju@aai.ee ABSTRACT: The variations of erythemally weighted ultraviolet (UV) irradiance and its relationships with atmospheric characteristics during 3 annual cycles (1998-2000) at 1 site (Tõravere, Estonia; 58.3°N, 26.5°E; 70 m above sea level) were studied, with the further aim to estimate the erythemal doses for past years. In clear sky conditions the daily erythemal dose and noon irradiance exhibit total-ozone-related asymmetry in the annual cycle, with 27% lower values at spring equinox than at autumnal equinox. The clear sky ratio of erythemally weighted to broadband (300 to 3000 nm) irradiance increases from (0.5 ± 0.25) × 10-4 to (2 ± 0.1) × 10-4 with an increase in solar elevation from 10° to 55°. In overcast low cloudiness conditions this ratio is higher. A simple empirical method to estimate the summer half-year erythemal dose for past years is proposed, and the doses were calculated for 1967-2000. A sharp drop in summer half-year sunshine duration and erythemal dose was found around 1975, with a following quasi-linear recovery to the values met in 1967-1975. A comparison with the measured and Total Ozone Mapping Spectrometer (TOMS)-derived data is provided for 1998-2000. In the fine summer of 1999 and the Œnormal¹ one of 2000, the measured, estimated and TOMS-derived half-year doses agreed to within 0.7%. In the extremely cloudy summer of 1998, the difference between the measured and estimated values was 1.7% and between the measured and TOMS-derived values 6%. KEY WORDS: Erythemal ultraviolet radiation · UV dose · UV index · Atmospheric turbidity · Total ozone · Cloud factor · Relative sunshine duration Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in CR Vol. 22, No. 3. Online publication date: November 04, 2002 Print ISSN: 0936-577X; Online ISSN: 1616-1572 Copyright © 2002 Inter-Research.

Drug-induced cutaneous photosensitivity: incidence, mechanism, prevention and management.

The interaction of sunlight with drug medication leads to photosensitivity responses in susceptible patients, and has the potential to increase the incidence of skin cancer. Adverse photosensitivity responses to drugs occur predominantly as a phototoxic reaction which is more immediate than photoallergy, and can be reversed by withdrawal or substitution of the drug. The bias and inaccuracy of the reporting procedure for these adverse reactions is a consequence of the difficulty in distinguishing between sunburn and a mild drug photosensitivity reaction, together with the patient being able to control the incidence by taking protective action. The drug classes that currently are eliciting a high level of adverse photosensitivity are the diuretic, antibacterial and nonsteroidal anti-inflammatory drugs (NSAIDs). Photosensitising chemicals usually have a low molecular weight (200 to 500 Daltons) and are planar, tricyclic, or polycyclic configurations, often with heteroatoms in their structures enabling resonance stabilisation. All absorb ultraviolet (UV) and/or visible radiation, a characteristic that is essential for the chemical to be regarded as a photosensitiser. The photochemical and photobiological mechanisms underlying the adverse reactions caused by the more photoactive drugs are mainly free radical in nature, but reactive oxygen species are also involved. Drugs that contain chlorine substituents in their chemical structure, such as hydrochlorthiazide, furosemide and chlorpromazine, exhibit photochemical activity that is traced to the UV-induced dissociation of the chlorine substituent leading to free radical reactions with lipids, proteins and DNA. The photochemical mechanisms for the NSAIDs that contain the 2-aryl propionic acid group involve decarboxylation as the primary step, with subsequent free radical activity. In aerated systems, the reactive excited singlet form of oxygen is produced with high efficiency. This form of oxygen is highly reactive towards lipids and proteins. NSAIDs without the 2-arylpropionic acid group are also photoactive, but with differing mechanisms leading to a less severe biological outcome. In the antibacterial drug class, the tetracyclines, fluoroquinolones and sulfonamides are the most photoactive. Photocontact dermatitis due to topically applied agents interacting with sunlight has been reported for some sunscreen and cosmetic ingredients, as well as local anaesthetic and anti-acne agents. Prevention of photosensitivity involves adequate protection from the sun with clothing and sunscreens. In concert with the preponderance of free radical mechanisms involving the photosensitising drugs, some recent studies suggest that diet supplementation with antioxidants may be beneficial in increasing the minimum erythemal UV radiation dose.

A Study of the Characteristics of Ultraviolet Radiation in Hong Kong

The characteristics of ultraviolet (UV) radiation in Hong Kong have been studied using UV measurements taken at the Hong Kong Observatory, King's Park meteorological station, and the Hong Kong Polytechnic University air monitoring station at Cape D'Aguilar. It is found that the ratio between the daily totals of erythemal UV radiation (UVE) and the global solar radiation (G) is mostly less than 0.05%. In Hong Kong, the UV Index (UVI) very often rises above 10 in a summer day from June to August. The summer UVI variation in Hong Kong is primarily affected by clouds rather than total ozone as the latter varies by about 20 to 30 Dobson Units during the season. Broadband instruments also tend to produce higher UVI values as compared with those obtained from a Brewer Spectrophotometer.

Influence of snow and clouds on erythemal UV radiation: Analysis of Swiss measurements and comparison with models

Global, direct and diffuse measurements of erythemal UV radiation with UV‐Biometer and radiative transfer calculations are used to estimate the influences of (1) a snow‐covered surface, (2) an overcast sky, and (3) a joined snow‐covered surface and overcast sky at Davos (1610 m asl, Swiss Alps). The influence of total ozone, zenith angle, and aerosol are first investigated. The influence of surface albedo and clouds are then estimated as a function of the zenith angle after normalization of the data to a fixed ozone amount. If the ground is covered with snow on clear‐sky days at Davos, erythemal irradiance increases by 15 to 25% due to multiple reflections between the surface and the atmosphere. This relative increase may reach 80% on overcast days. The highly significant dependence of the albedo on solar elevation is most probably due to inhomogeneities in the surrounding terrain leading to a strong non‐Lambertian behavior. The impact of clouds on radiation is highly variable: on overcast days with a snow free surface, erythemal UV radiation at Davos is reduced to a level ranging between 8% (very thick cloud cover) and 70% (thin cloud layer) relative to the radiation under clear‐sky conditions.