Erythemal UV Research Articles

Reconstruction and analysis of erythemal UV radiation time series from Hradec Králové (Czech Republic) over the past 50 years

Abstract. This paper evaluates the variability of erythemal ultraviolet (EUV) radiation from Hradec Králové (Czech Republic) in the period 1964–2013. The EUV radiation time series was reconstructed using a radiative transfer model and additional empirical relationships, with the final root mean square error of 9.9 %. The reconstructed time series documented the increase in EUV radiation doses in the 1980s and the 1990s (up to 15 % per decade), which was linked to the steep decline in total ozone (10 % per decade). The changes in cloud cover were the major factor affecting the EUV radiation doses especially in the 1960s, 1970s, and at the beginning of the new millennium. The mean annual EUV radiation doses in the decade 2004–2013 declined by 5 %. The factors affecting the EUV radiation doses differed also according to the chosen integration period (daily, monthly, and annually): solar zenith angle was the most important for daily doses, cloud cover, and surface UV albedo for their monthly means, and the annual means of EUV radiation doses were most influenced by total ozone column. The number of days with very high EUV radiation doses increased by 22 % per decade, the increase was statistically significant in all seasons except autumn. The occurrence of the days with very high EUV doses was influenced mostly by low total ozone column (82 % of days), clear-sky or partly cloudy conditions (74 % of days) and by increased surface albedo (19 % of days). The principal component analysis documented that the occurrence of days with very high EUV radiation doses was much affected by the positive phase of North Atlantic Oscillation with an Azores High promontory reaching over central Europe. In the stratosphere, a strong Arctic circumpolar vortex and the meridional inflow of ozone-poor air from the southwest were favorable for the occurrence of days with very high EUV radiation doses. This is the first analysis of the relationship between the high EUV radiation doses and macroscale circulation patterns, and therefore more attention should be given also to other dynamical variables that may affect the solar UV radiation on the Earth surface.

Reticulon-1 and Reduced Migration toward Chemoattractants by Macrophages Differentiated from the Bone Marrow of Ultraviolet-Irradiated and Ultraviolet-Chimeric Mice.

The ability of macrophages to respond to chemoattractants and inflammatory signals is important for their migration to sites of inflammation and immune activity and for host responses to infection. Macrophages differentiated from the bone marrow (BM) of UV-irradiated mice, even after activation with LPS, migrated inefficiently toward CSF-1 and CCL2. When BM cells were harvested from UV-irradiated mice and transplanted into naive mice, the recipient mice (UV-chimeric) had reduced accumulation of elicited monocytes/macrophages in the peritoneal cavity in response to inflammatory thioglycollate or alum. Macrophages differentiating from the BM of UV-chimeric mice also had an inherent reduced ability to migrate toward chemoattractants in vitro, even after LPS activation. Microarray analysis identified reduced reticulon-1 mRNA expressed in macrophages differentiated from the BM of UV-chimeric mice. By using an anti-reticulon-1 Ab, a role for reticulon-1 in macrophage migration toward both CSF-1 and CCL2 was confirmed. Reticulon-1 subcellular localization to the periphery after exposure to CSF-1 for 2.5 min was shown by immunofluorescence microscopy. The proposal that reduced reticulon-1 is responsible for the poor inherent ability of macrophages to respond to chemokine gradients was supported by Western blotting. In summary, skin exposure to erythemal UV radiation can modulate macrophage progenitors in the BM such that their differentiated progeny respond inefficiently to signals to accumulate at sites of inflammation and immunity.

Estimating Cloud and Aerosol UV Modification Factors Based on Spectral Measurement from the Brewer Spectrophotometer

Cloud and aerosol modification factors are investigated in the spectral range of ultraviolet (UV) to correct for cloud and aerosol extinction effects from clear sky irradiance. The cloud modification factor (CMF) and aerosol modification factor (AMF) are estimated using radiative transfer model (RTM) simulations and ground-based observations in Seoul, Korea. The modification factors show a spectral dependence within the spectral range of 300 to 360 nm, which is the range used to estimate erythemal UV. The CMF and AMF values are estimated with high spectral resolution with considerations of solar zenith angle (SZA), cloud/aerosol amount, and total ozone variation. From the simulation studies, the variation in the CMFs within the spectral range of 300–360 nm is estimated to be 0.031–0.055, which is twice as large as the decrease in CMFs resulting from a SZA increase of 10°. In addition, the CMFs estimated from observational data show significant spectral dependence, varying from 2.5% to 10.0%. Because of the small aerosol optical depth (AOD) value, however, the variation in the AMF calculated from simulations is estimated to be between 0.007 and 0.045, indicating lower spectral dependence than the CMF. Furthermore, the spectral difference in the AMF calculated from observational data is insignificant relative to the daily-averaged total ozone error and uncertainties related to the reference irradiance spectrum under aerosol-free conditions.

TEMIS UV product validation using NILU-UV ground-based measurements in Thessaloniki, Greece

Abstract. This study aims to cross-validate ground-based and satellite-based models of three photobiological UV effective dose products: the Commission Internationale de l'Éclairage (CIE) erythemal UV, the production of vitamin D in the skin, and DNA damage, using high-temporal-resolution surface-based measurements of solar UV spectral irradiances from a synergy of instruments and models. The satellite-based Tropospheric Emission Monitoring Internet Service (TEMIS; version 1.4) UV daily dose data products were evaluated over the period 2009 to 2014 with ground-based data from a Norsk Institutt for Luftforskning (NILU)-UV multifilter radiometer located at the northern midlatitude super-site of the Laboratory of Atmospheric Physics, Aristotle University of Thessaloniki (LAP/AUTh), in Greece. For the NILU-UV effective dose rates retrieval algorithm, a neural network (NN) was trained to learn the nonlinear functional relation between NILU-UV irradiances and collocated Brewer-based photobiological effective dose products. Then the algorithm was subjected to sensitivity analysis and validation. The correlation of the NN estimates with target outputs was high (r = 0. 988 to 0.990) and with a very low bias (0.000 to 0.011 in absolute units) proving the robustness of the NN algorithm. For further evaluation of the NILU NN-derived products, retrievals of the vitamin D and DNA-damage effective doses from a collocated Yankee Environmental Systems (YES) UVB-1 pyranometer were used. For cloud-free days, differences in the derived UV doses are better than 2 % for all UV dose products, revealing the reference quality of the ground-based UV doses at Thessaloniki from the NILU-UV NN retrievals. The TEMIS UV doses used in this study are derived from ozone measurements by the SCIAMACHY/Envisat and GOME2/MetOp-A satellite instruments, over the European domain in combination with SEVIRI/Meteosat-based diurnal cycle of the cloud cover fraction per 0. 5° × 0. 5° (lat × long) grid cells. TEMIS UV doses were found to be ∼ 12.5 % higher than the NILU NN estimates but, despite the presence of a visually apparent seasonal pattern, the R2 values were found to be robustly high and equal to 0.92–0.93 for 1588 all-sky coincidences. These results significantly improve when limiting the dataset to cloud-free days with differences of 0.57 % for the erythemal doses, 1.22 % for the vitamin D doses, and 1.18 % for the DNA-damage doses, with standard deviations of the order of 11–13 %. The improvement of the comparative statistics under cloud-free cases further testifies to the importance of the appropriate consideration of the contribution of clouds in the UV radiation reaching the Earth's surface. For the urban area of Thessaloniki, with highly variable aerosol, the weakness of the implicit aerosol information introduced to the TEMIS UV dose algorithm was revealed by comparison of the datasets to aerosol optical depths at 340 nm as reported by a collocated CIMEL sun photometer, operating in Thessaloniki at LAP/AUTh as part of the NASA Aerosol Robotic Network.

Modern approach to study trends in global ultraviolet index maps variation over solar cycles by the complementary use of time series, mathematical metrics and artificial neural networks

The information on how much total solar energy and its ultraviolet component can be acquired from the Sun at particular locations is vital for climatology, ecology, health-care but also for some branches of modern industry (e.g. constructions, solar power technologies, materials science, pharmacy, optometry and optics). The Discrete Fourier Transform applied to study UV index (UVI) time series in the last solar cycle at selected locations (71 in Europe and 114 in the World) has revealed periodicity and correlation between the amplitude and latitude. The main frequency peak with amplitude varying from 0.963 to 5.625 shows the UVI periodicity of 315–316 days at each location. The greatest variation in UVI occurs at two latitude bands distanced by 65° (Northern hemisphere from 30° to 50° and Southern hemisphere from −50° to −20°); the lowest variation is observed near the equatorial region.A completely novel method for a comparative analysis of UVI measured by satellites (Nimbus-7/TOMS (Total Ozone Mapping Spectrometer), 1978–1991; Meteor-3/TOMS, 1991–1995; Earth-Probe/TOMS, 1996–2005) for the whole globe in the range from 1978 to 2005, has been developed and applied. A few mathematical metrics (Manhattan, Euclidean, Bhattacharyya, Hellinger) applied for the studies of monthly averaged maps of UVI from 1978 to 2005 reveal different character of UVI variations at selected latitudes and on the global scale. The topological Pompeiu–Hausdorff metric was introduced as a measure and used to visualize the variations on UVI maps. This metric, tolerant to small positions errors, also cancels the errors which come from those in positioning satellites, blank regions caused by the satellite motion or clouds.The feed forward, multilayered supervised artificial neural network dedicated to the reconstruction of world maps of erythemal Ultraviolet index (UV index) was constructed and trained using three different sets of data selected from 1978 to 2005. A combined analysis made using Manhattan, Euclidean, Bhattacharyya, Hellinger and topological Pompeiu–Hausdorff metrics has revealed large unconnected and inhomogeneous areas of high variability in UVI maps. The modeling of the long term variation in UVI during the whole sun activity cycle helped to understand trends and predict the direction of future variations in UV radiation level. The quality of prediction was evaluated using a newly proposed approach based on Pompeiu–Hausdorff metric.

Concurrent evaluation of personal damaging and beneficial UV exposures over an extended period

Personal exposure to solar ultraviolet radiation (UVR) is acknowledged as having both positive and negative effects on human health. This study aimed to measure concurrently the personal erythemal UV, UVA and vitamin D effective exposures of participants in each season of a year. Participants were all indoor office workers located at two different sites less than 6.5 km apart at the sub-tropical location of Toowoomba (27°33′S 151°55′E). The subjects wore a combined dosimeter badge horizontally on the shoulder for a minimum of one week in each season; this badge used 8-methoxypsoralen film to record the UVA waveband and polyphenylene oxide film for the erythemal and the vitamin D effective UV wavebands. The results show that median erythemal exposure was highest during the spring and lowest during winter, as was the vitamin D effective exposure. Median UVA exposures were at a similar level in winter and summer, autumn was higher (double) and spring at a lower level. The duration and time of day participants spent outdoors changed in each season; in winter, participants spent an average of 101 minutes outdoors between 10:00–14:00 h over the week, whereas in summer this fell to 79 minutes even though they were outdoors more often. The daily UVA/UVB ratio is lowest between 10:00–14:00 h and also changes with the season resulting in the differences between the distributions of exposure for each of the wavebands. Each category of exposures must be assessed individually as each season and each waveband has different distributions. The results also demonstrate that the dual film dosimeter developed and characterized with a calibration to three different biological responses, is an effective device for the concurrent measurement of erythemal UV, UVA and vitamin D effective UV exposures for periods of up to seven days.

Validación de los datos de radiación solar UV del Ozone Monitoring Instrument (OMI) a partir de medidas con base en tierra en la costa mediterránea

<p align="justify">The erythemal UV daily dose (EDD) and the local noon UV Index (UVI) obtained from the Ozone Monitoring Instrument (OMI), on board NASA’s Aura satellite, have been validated for the period 2005-2013 using ground based measurements at 5 different sites in the Mediterranean coast: Murcia, Valencia, Palma de Mallorca, Barcelona and Rome (where only measurements of the local noon UVI were available). Ground based measurements were made using YES UVB-1 radiometers in Murcia, Valencia, Palma de Mallorca and Barcelona, and a Brewer MKIV 067 spectrophotometer in Rome. The results of the validation showed good agreement between the satellite instrument and the ground based measurements, although the OMI values overestimate the ground based measurements, being the difference between both types of measurements maximum during the spring and summer, and minimum during autumn and winter. The evolution of the EDD shows a clear seasonal behavior for all measuring sites for both, ground based and satellite data, with maximum values in summer (June and July) and minimum values in winter (December and January). A high percentage of cases (>80%) showed minimum differences (0-1 UVI units) between the UVI obtained by OMI and the UVI obtained by ground based instruments for all measuring sites. In every measuring site, high (6-7) or very high (8-10) UVI values are reached for a high percentage of the days of the analyzed period, but very few extreme (≥11) UVI values are reached.</p>

Influence of cloudiness on erythemal solar irradiance in Marsaxlokk, Malta: Two case studies

The effects of cloudiness on solar ultraviolet irradiance recorded between May and October 2012 at Marsaxlokk, Malta, are analysed. A statistical analysis of cloudiness is carried out, with clear skies (0–2oktas) proving to be the most frequent conditions under total and low cloud cover. Hence, the dependence of erythemal UV solar irradiance (UVER) on total and low cloud cover is evaluated. In all cases, low clouds show higher attenuation. The effects of total cloud cover and low clouds on UVER are evaluated by means of the cloud modification factor (CMF) that is defined as the ratio between the measured irradiance and the estimated irradiance under cloud-free conditions. The results show that the effect on UVER is less than on global solar irradiance and that UVER transmissivity under overcast conditions can reach 50%. The effect of cloud optical thickness (COT) on UVER under all conditions shows a clear exponential dependence. The analysis shows that for fairly thick clouds with a COT of 10, the UVER reaching the Earth’s surface is about 50% of its cloud-free value. The CMFUVER is found to decrease from 0.7 for COT=0.5 to 0.25 for COT=30. 10-min estimated COT from global solar irradiance are then compared with the GOME2 instrument. The correlation is found to be low. The influence of COT is studied by observing the evolution of irradiance on two cloudy days. When comparing the 10-min CMF under high COT for UVER and global irradiance, the first variable is found to be slightly higher than the second. As a consequence, changes in the ultraviolet index (UVI) due to COT effects are then described. Finally, the results obtained are compared with those from previous studies performed by different authors.

Online educative activities for solar ultraviolet radiation based on measurements of cloud amount and solar exposures

A set of online activities for children and the community that are based on an integrated real-time solar UV and cloud measurement system are described. These activities use the functionality of the internet to provide an educative tool for school children and the public on the influence of cloud and the angle of the sun above the horizon on the global erythemal UV or sunburning UV, the diffuse erythemal UV, the global UVA (320–400nm) and the vitamin D effective UV. Additionally, the units of UV exposure and UV irradiance are investigated, along with the meaning and calculation of the UV index (UVI). This research will help ensure that children and the general public are better informed about sun safety by improving their personal understanding of the daily and the atmospheric factors that influence solar UV radiation and the solar UV exposures of the various wavebands in the natural environment. The activities may correct common misconceptions of children and the public about UV irradiances and exposure, utilising the widespread reach of the internet to increase the public's awareness of the factors influencing UV irradiances and exposures in order to provide clear information for minimizing UV exposure, while maintaining healthy, outdoor lifestyles.

Spectral dependence on the correction factor of erythemal UV for cloud, aerosol, total ozone, and surface properties: A modeling study

Radiative transfer model simulations were used to investigate the erythemal ultraviolet (EUV) correction factors by separating the UV-A and UV-B spectral ranges. The correction factor was defined as the ratio of EUV caused by changing the amounts and characteristics of the extinction and scattering materials. The EUV correction factors (CFEUV) for UV-A [CFEUV(A)] and UV-B [CFEUV(B)] were affected by changes in the total ozone, optical depths of aerosol and cloud, and the solar zenith angle. The differences between CFEUV(A) and CFEUV(B) were also estimated as a function of solar zenith angle, the optical depths of aerosol and cloud, and total ozone. The differences between CFEUV(A) and CFEUV(B) ranged from −5.0% to 25.0% for aerosols, and from −9.5% to 2.0% for clouds in all simulations for different solar zenith angles and optical depths of aerosol and cloud. The rate of decline of CFEUV per unit optical depth between UV-A and UV-B differed by up to 20% for the same aerosol and cloud conditions. For total ozone, the variation in CFEUV(A) was negligible compared with that in CFEUV(B) because of the effective spectral range of the ozone absorption band. In addition, the sensitivity of the CFEUVs due to changes in surface conditions (i.e., surface albedo and surface altitude) was also estimated by using the model in this study. For changes in surface albedo, the sensitivity of the CFEUVs was 2.9%–4.1% per 0.1 albedo change, depending on the amount of aerosols or clouds. For changes in surface altitude, the sensitivity of CFEUV(B) was twice that of CFEUV(A), because the Rayleigh optical depth increased significantly at shorter wavelengths.

Dual calibrated dosimeter for simultaneous measurements of erythemal and vitamin D effective solar ultraviolet radiation

A miniaturized ultraviolet radiation (UV) dosimeter based on polyphenylene oxide (PPO) has been dual calibrated for both erythemal and vitamin D effective exposures (UVB 280 – 320nm) over extended periods up to five days. Optimal human health requires a balanced amount of UVB exposure as both too much and too little have different but serious potential health consequences. Dosimetry is an established method of measuring specific UV exposures to an object or subject. PPO dosimeters have previously been used to measure the erythemally effective UV exposure. An extension of this use is to dual calibrate the miniaturized dosimeter which will also enable measurement of vitamin D effective exposures. By calibration to the erythemal and vitamin D effective action spectra, PPO dosimeters were able to record both types of biologically effective exposure as both are active within the UVB waveband. Dose response tests were conducted in each season by exposure to solar UV with the corresponding dual calibrations made for each season. The calibration provided an R2 of 0.95–0.99 for erythemal UV and an R2 of 0.99 for vitamin D effective UV. The successful outcome of this testing has established that PPO is suitable for use as a long term, dual calibrated dosimeter provided the film is seasonally calibrated. This enables one dosimeter to provide two sets of exposure results. The combination of dual calibration and the long term exposure potential of PPO makes the PPO dosimeter more versatile and increases the scope of UV field research on erythemal UV and vitamin D effective UV in the future.

Impact of UV-A radiation on erythemal UV and UV-index estimation over Korea

Because total UV (TUV) in the UV-A region is 100 times higher than in the UV-B region, UV-A is a considerable component when calculating erythemal UV (EUV) and UV-index. The ratio of EUV to TUV in the UV-A value [EUV(A)/TUV(A)] is investigated to convert the EUV(A) from TUV(A) for broadband observation. The representative value of EUV(A)/TUV(A), from the simulation study, is 6.9×10−4, changing from 6.1×10−4 to 7.0×10−4 as aerosol optical depth, total ozone and solar zenith angle change. By adopting the observational data of EUV(B) and TUV(A) from UV-biometer measurements at Yonsei University [(37.57°N, 126.95°E), 84 m above sea level], the EUV irradiance increases to 15% of EUV(B) due to the consideration of EUV(A) from the data of TUV(A) observation. Compared to the total EUV observed from the Brewer spectrophotometer at the same site, the EUV(B) from the UV-biometer observes only 95% of total EUV, and its underestimation is caused by neglecting the effect of UV-A. However, the sum of EUV(B) and EUV(A) [EUV(A+B)] from two UV-biometers is 10% larger than the EUV from the Brewer spectrophotometer because of the spectral overlap effect in the range 320–340 nm. The correction factor for the overlap effect adjusts 8% of total EUV.

Influence of the El Niño southern oscillation on the total ozone column and clear-sky ultraviolet radiation over China

The influence of the El Niño Southern Oscillation (ENSO) on the total ozone column (TOC) and clear-sky ultraviolet (UV) radiation over China is analysed using various datasets and a chemistry-climate model. Higher TOC values than normal are found over most parts of China during El Niño events. La Niña events have almost the opposite effect on TOC anomalies over China. It is particularly noticeable that the maximum response of the TOC to ENSO shifts northward from southern China in winter to northern China in summer. The seasonal shift of the centre of TOC anomalies is related to the seasonal shift of the location of the East Asia westerly jet, accompanied by tropopause height changes and anomalous circulations induced by Rossby wave trains along the jet. The differences in the TOC between El Niño and La Niña events can cause up to 6–10% clear-sky erythemal UV changes over the middle and lower reaches of the Yangtze River in winter and the northwestern Tibetan Plateau during spring, which may have public health consequences.

Influence of cloud fraction and snow cover to the variation of surface UV radiation at King Sejong station, Antarctica

This study investigated how cloud fraction and snow cover affect the variation of surface ultraviolet (UV) radiation by using surface Erythemal UV (EUV) and Near UV (NUV) observed at the King Sejong Station, Antarctica. First the Radiative Amplification Factor (RAF), the relative change of surface EUV according to the total-column ozone amount, is compared for different cloud fractions and solar zenith angles (SZAs). Generally, all cloudy conditions show that the increase of RAF as SZA becomes larger, showing the larger effects of vertical columnar ozone. For given SZA cases, the EUV transmission through mean cloud layer gradually decreases as cloud fraction increases, but sometimes the maximum of surface EUV appears under partly cloudy conditions. The high surface EUV transmittance under broken cloud conditions seems due to the re-radiation of scattered EUV by cloud particles. NUV transmission through mean cloud layer also decreases as cloud amount increases but the sensitivity to the cloud fraction is larger than EUV. Both EUV and NUV radiations at the surface are also enhanced by the snow cover, and their enhancement becomes higher as SZA increases implying the diurnal variation of surface albedo. This effect of snow cover seems large under the overcast sky because of the stronger interaction between snow surface and cloudy sky.

Towards analysis and predicting maps of ultraviolet index from experimental astronomical parameters (solar elevation, total ozone level, aerosol index, reflectivity). Artificial neural networks global scale approach

UV radiation is an important problem in climatology, ecology but also has direct effect on human health. A novel method for analysis and prediction of global erythemal UV for clear-sky at noon at any localisation, expressed as the UV index, has been proposed. The supervised artificial neural networks (ANN) were trained using purely experimental astronomical parameters (input: solar elevation, total ozone level, aerosol index, reflectivity and required output: erythemal local noon UV irradiance expressed as the UV index) for all dates from a 3-year representative period (2001–2003) collected by Total Ozone Mapping Spectrometer (TOMS). The input data from the 3-year period provide three sets of 1095 grids, each consisting of 288×180 i.e. 56,764,800 training vectors for total ozone level, aerosol index, reflectivity, while the output data provide only one set of data of the same resolution. The trained network delivers a good long-term representation of the physical problem as it is able to predict clear-sky global UV index maps (UVI for any location and date) with an excellent accuracy close to the detection error (3%, 0.5 unit of UVI). The omission of data on aerosol index (slightly) and reflectivity (highly) deteriorates the quality of UVI prediction (MSPE error 6.4%, 1 unit of UVI) but also confirms the importance of total ozone level for the UVI prediction. The neglect of data on aerosol index and reflectivity evidently removes the inhomogeneities and results in smoother and less reliable UVI maps. Reflectivity plays a very important role in variation of UV radiation level. The results are presented in the form of 2D rectangular maps (WGS-84 projection) of UV index. The neural network approach to UVI forecasting and analysis yields reasonable results and can be considered as an alternative to traditional approaches mainly based on radiative-transfer or regression models.

Long-term comparisons of UV index values derived from a NILU-UV instrument, NWS, and OMI in the New York area.

A comparison is presented of UV index (UVI) values obtained under different cloud conditions from a Norwegian Institute for Air Research UV (NILU-UV) instrument, the ozone monitoring instrument (OMI) onboard the Aura satellite, and the National Weather Service (NWS) model for the time period of 2010-2014. The NILU-UV irradiance meter is a ground-based, multi-channel, moderate bandwidth filter instrument. UVI values derived from measurements by a NILU-UV instrument deployed in the New York area (40.74°N, -74.03°E) to monitor the erythemal UV radiation from 2010 to present is compared to UVI values derived from OMI measurements and predicted by the NWS model. OMI overestimated the UVI values by 13.06% for all cloud conditions compared with the UVI values derived from measurements by the NILU-UV instrument. The heavier the cloud cover, the higher the overestimation. The mean relative difference between the UVI derived from the NWS model and from NILU-UV measurements was 11.54%. The UVI prediction by NWS was also overestimated under cloudy conditions. Under overcast conditions the NWS predictions of UVI values differ significantly from those derived from NILU-UV measurements, yielding a correlation of only 0.8025 and a mean relative difference of 28.25%.

Occupational UV exposure in French outdoor workers.

Occupational ultraviolet (UV) exposure was evaluated in a population-based sample in France. A random survey was conducted in 2012 in individuals aged 25 to 69 years. The median daily standard erythemal UV dose (SED) was estimated from exposure time and place and matched to satellite UV records. A total of 889 individuals were exposed to solar UV with highest doses observed among gardeners (1.19 SED), construction workers (1.13 SED), agricultural workers (0.95 SED), and culture/art/social science workers (0.92 SED). Information and communication technology, industry, and transport workers were highly exposed (>0.70 SED). Significant factors associated with high occupational UV exposure were sex (P < 0.0001), phototype (P = 0.0003), and taking lunch outdoors (P < 0.0001). This study identified not only expected occupations with high UV exposure but also unexpected occupations with high exposures. This could serve as a basis for future prevention.

The relationship between disability-adjusted life years of cataracts and ambient erythemal ultraviolet radiation in China.

BackgroundCataracts are one of the major public health problems worldwide. Ultraviolet radiation (UVR) is one of the risk factors for cataract development. We analyzed the relationship between disability-adjusted life year (DALY) rates of cataracts and UVR exposure in China.MethodsDALY rates of cataracts and UVR exposure in 31 regions of China were calculated based on data from the Second China National Sample Survey on Disability and the United States’ National Aeronautics and Space Administration database. The relationship between the DALY rates of cataracts and UVR was estimated by Spearman rank correlation analysis and linear regression analysis.ResultsThe elderly (≥65 years) had higher DALY rates of cataracts than the whole population. The DALY rate of cataracts in the agricultural population was higher than that observed in the non-agricultural population. The DALY rates of cataracts were positively associated with UVR The DALY rates of cataracts in regions with higher UVR were higher than those in regions with lower UVR. An increase in the daily ambient erythemal UVR of 1000 J/m2 was associated with an increase in the DALY rates of cataracts by 92 DALYs/100 000 (R2 = 0.676) among the whole population, 34 DALYs/100 000 among the population <65 years old (R2 = 0.423), 607 DALYs/100 000 among the population aged 65–74 years (R2 = 0.617), and by 1342 DALYs/100 000 among the population ≥75 years old (R2 = 0.758).ConclusionsDALY rates of cataracts increased with increases in UVR exposure in 31 regions of China. Greater exposure to UVR increases the disease burden of cataracts in the whole population, especially in the elderly and among the agricultural population.

Towards modelling ultraviolet index in global scale. Artificial neural networks approach

A unique method for the reconstruction of global maps of erythemal Ultraviolet index (UV index) is proposed. The feed forward, multilayered supervised artificial neural network dedicated to this task was constructed and trained using purely experimental meteorological parameters (covariates: date, latitude, UV index for previous day, two days earlier and one year earlier and response variable: erythemal local noon UV irradiance expressed as UV index) for all dates from a 3-year range period (2001–2003) collected by Total Ozone Mapping Spectrometer, TOMS. The data from the 3-year period provide 1095 grids of 288×180, i.e. 56,764,800 training vectors. The 4-year period of 2001–2004 was used for the forecast validation. Global UV index maps for any location and date can be predicted with accuracy comparable to the detection error (5%, 0.7 unit of UV index). The prediction is better than that obtained for the artificial neural network using ozone levels, aerosols and reflectivity as inputs or that obtained for the network using ozone levels as inputs (6%). The accuracy of prediction is much higher for medium and extremely high UV index in comparison with that for low UV index. The novelty of our approach relies also on using only archival data of UV index and not taking any additional meteorological or environmental data as predictors.

Relations between erythemal UV dose, global solar radiation, total ozone column and aerosol optical depth at Uccle, Belgium

Abstract. At Uccle, Belgium, a long time series (1991–2013) of simultaneous measurements of erythemal ultraviolet (UV) dose (Sery), global solar radiation (Sg), total ozone column (Q_{O3}$) and aerosol optical depth (τaer) (at 320.1 nm) is available, which allows for an extensive study of the changes in the variables over time. Linear trends were determined for the different monthly anomalies time series. Sery, Sg and QO3 all increase by respectively 7, 4 and 3% per decade. τaer shows an insignificant negative trend of −8% per decade. These trends agree with results found in the literature for sites with comparable latitudes. A change-point analysis, which determines whether there is a significant change in the mean of the time series, is applied to the monthly anomalies time series of the variables. Only for Sery and QO3, was a significant change point present in the time series around February 1998 and March 1998, respectively. The change point in QO3 corresponds with results found in the literature, where the change in ozone levels around 1997 is attributed to the recovery of ozone. A multiple linear regression (MLR) analysis is applied to the data in order to study the influence of Sg, QO3 and τaer on Sery. Together these parameters are able to explain 94% of the variation in Sery. Most of the variation (56%) in Sery is explained by Sg. The regression model performs well, with a slight tendency to underestimate the measured Sery values and with a mean absolute bias error (MABE) of 18%. However, in winter, negative Sery are modeled. Applying the MLR to the individual seasons solves this issue. The seasonal models have an adjusted R2 value higher than 0.8 and the correlation between modeled and measured Sery values is higher than 0.9 for each season. The summer model gives the best performance, with an absolute mean error of only 6%. However, the seasonal regression models do not always represent reality, where an increase in Sery is accompanied with an increase in QO3 and a decrease in τaer. In all seasonal models, Sg is the factor that contributes the most to the variation in Sery, so there is no doubt about the necessity to include this factor in the regression models. The individual contribution of τaer to Sery is very low, and for this reason it seems unnecessary to include τaer in the MLR analysis. Including QO3, however, is justified to increase the adjusted R2 and to decrease the MABE of the model.