UV index experimental values during the years 2000 and 2001 from the Spanish broadband UV-B radiometric network

Characterization of the effects of vitamin D synthesis and sunburn in the population due to solar radiation exposure using PROBIT methodology

The main objective of this work is to present a set of equations that relates exposure time to solar radiation, the ultraviolet index (UVI), and its effects, both positive (vitamin D synthesis) and negative (sunburns), including the influence of repeated doses and the incorporation of protective factors. To do so, expressions are proposed for both effects and a time range is specified where repeated doses can be applied. Moreover, we propose expressions (PROBIT equations) that relate the percentage of a population that would reach the recommended daily amount of vitamin D and the repeated dosage to which the population is exposed for skin types I to IV. For all the cases studied, protective factors, such as the use of clothes or sunscreens, were taken into account. Additionally, comparisons were made based on skin types between the generation of daily vitamin D and the onset of sunburn, being able to establish a percentage of those who would suffer from first-degree sunburns when this population reached the recommended daily amount of vitamin D. Thus, it can be noted that when a large percentage of a population wants to obtain the recommended daily allowance of vitamin D of 2000 IU or more, and by exposing a small portion of skin to solar radiation, a considerable percentage of that population would suffer from first-degree sunburn as vitamin D generation is related to the area of exposed skin. Therefore, by increasing the area of skin that is exposed to solar radiation, vitamin D needs can be safely met even with higher daily amounts.

TEMPERATURE CORRECTION OF HISTORIC ERYTHEMA EFFECTIVE SOLAR UV DATA RESULTING IN A CONTINUOUS 25-YEAR DATA SET AT CHILTON, UK

Public Health England has a solar network which has been established for over 25 years which measures erythema effective UV, UVA and photopic radiation. At the Chilton site there are erythema effective solar UV data available for 25 years from 1991 to 2015. Until October 2004, the data were gathered using a Solar Light R-B 500 radiometer (SL-500), which is not temperature regulated. From October 2004, the data are from a temperature regulated Solar Light R-B 501 radiometer (SL-501). A temperature correction model has been developed using overlapping SL-500 and SL-501 data from 2006 and verified using overlapping SL-500 and SL-501 data from 2005. This correction has been applied to the non-temperature regulated SL-500 Chilton data from 1991 to 2004 resulting in a 25-year dataset of SL-501 equivalent data for the analysis of long-term trends. The development and verification of this model is described.

International Intercomparison of Solar UVR Spectral Measurement Systems in Melbourne in 2013

Monitoring ambient solar UVR levels provides information on how much there is in both real time and historically. Quality assurance of ambient measurements of solar UVR is critical to ensuring accuracy and stability and this can be achieved by regular intercomparisons of spectral measurement systems with those of other organizations. In October and November of 2013 a solar UVR spectroradiometer from Public Health England (PHE) was brought to Melbourne for a campaign of intercomparisons with a new Bentham spectrometer of Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) and one at the Australian Bureau of Meteorology (BOM), supported by New Zealand's National Institute for Water and Atmosphere (NIWA). Given all three spectroradiometers have calibrations that are traceable to various national standards, the intercomparison provides a chance to determine measurement uncertainties and traceability that support UV measurement networks in Australia, New Zealand and the UK. UV Index measurements from all three systems were compared and ratios determined for clear sky conditions when the scans from each instrument were within 2 min of each other. While wavelengths below 305 nm showed substantial differences between the PHE unit and the two other systems, overall the intercomparison results were encouraging, with mean differences in measured UV Index between the BOM/NIWA and those of PHE and ARPANSA of <0.1% and 7.5%, respectively.

Autonomous portable solar ultraviolet spectroradiometer (APSUS) - a new CCD spectrometer system for localized, real-time solar ultraviolet (280-400 nm) radiation measurement

Terrestrial solar ultraviolet (UV) radiation has significant implications for human health and increasing levels are a key concern regarding the impact of climate change. Monitoring solar UV radiation at the earth's surface is therefore of increasing importance. A new prototype portable CCD (charge-coupled device) spectrometer-based system has been developed that monitors UV radiation (280-400 nm) levels at the earth's surface. It has the ability to deliver this information to the public in real time. Since the instrument can operate autonomously, it is called the Autonomous Portable Solar Ultraviolet Spectroradiometer (APSUS). This instrument incorporates an Ocean Optics QE65000 spectrometer which is contained within a robust environmental housing. The APSUS system can gather reliable solar UV spectral data from approximately April to October inclusive (depending on ambient temperature) in the UK. In this study the new APSUS unit and APSUS system are presented. Example solar UV spectra and diurnal UV Index values as measured by the APSUS system in London and Weymouth in the UK in summer 2012 are shown.

Measurement and analysis of broadband UVB solar radiation in Spain

Measurements of broadband UVB irradiance (290-315 nm) at 14 locations in Spain for the period 2000-2009 have been used to generate instantaneous, hourly and daily values of irradiance (W m(-2)) and radiant exposure (kJ m(-2)). These measurements, and its statistical indices, have been analyzed. For the UVB irradiance, the values corresponding to July (maximum) and December (minimum) have been analyzed as representative of the year during the whole period for all locations. For the UVB radiant exposure, the temporal evolution of daily values has been evaluated for all locations to estimate an average yearly behavior. The accumulated radiant exposure for an average year has also been studied for each location. Finally, to determine possible trends in the evolution of the UVB levels, the linear regressions for the mean daily values for all locations have been determined.

Effects of solar UV radiation on aquatic ecosystems and interactions with climate change

Recent results continue to show the general consensus that ozone-related increases in UV-B radiation can negatively influence many aquatic species and aquatic ecosystems (e.g., lakes, rivers, marshes, oceans). Solar UV radiation penetrates to ecological significant depths in aquatic systems and can affect both marine and freshwater systems from major biomass producers (phytoplankton) to consumers (e.g., zooplankton, fish, etc.) higher in the food web. Many factors influence the depth of penetration of radiation into natural waters including dissolved organic compounds whose concentration and chemical composition are likely to be influenced by future climate and UV radiation variability. There is also considerable evidence that aquatic species utilize many mechanisms for photoprotection against excessive radiation. Often, these protective mechanisms pose conflicting selection pressures on species making UV radiation an additional stressor on the organism. It is at the ecosystem level where assessments of anthropogenic climate change and UV-related effects are interrelated and where much recent research has been directed. Several studies suggest that the influence of UV-B at the ecosystem level may be more pronounced on community and trophic level structure, and hence on subsequent biogeochemical cycles, than on biomass levels per se.

UV Index on tilted surfaces

Solar ultraviolet erythemal irradiance (UVER) has been studied on inclined planes with different orientations in Valencia, Spain. To do this a platform was designed that could turn through 90 degrees on its own axis. The radiometers were inclined at an angle close to the latitude of Valencia (39.5 degrees N). Using two timers the platform could be turned through 90 degrees every 5 min. On clear or partially cloudy days, including those with different turbidity values, it was observed that the UVER showed a maximum at 1200 h GMT, very close to solar noon, in the north and south positions, while the maximum for east and west orientations was found at approximately one hour before and one hour after midday respectively. It was also observed how the irradiance for the south orientation was greater and for the north was less than for the horizontal plane, as well as the opposite performances of the east and west orientations, for four days close to the summer and winter solstices and each equinox. Some experimental results were also compared with the results from the SMARTS2.9 model for the same conditions. It was found that the model frequently overestimated the experimental data. With respect to the maximum calculated UV Index in the different planes this was always higher for the south orientation than for the north, while it was similar for east and west orientations throughout the year. Finally the accumulated erythemal dosage for the considered period was obtained as a function of phototype and orientation, confirming that the accumulated erythemal dosage decreased by around 37% in the north orientation compared to the horizontal value, while in the south position it was only 6% less and some 20% and 15% less in the east and west positions, respectively.

Modified Calibration Procedures for a Yankee Environmental System UVB-1 Biometer Based on Spectral Measurements with a Brewer Spectrophotometer

The calibration of the erythemal irradiance measured by a Yankee Environmental System (YES) UVB-1 biometer is presented using two methods of calibration with a wide range of experimental solar zenith angles (SZAs) and ozone values. The calibration is performed through simultaneous spectral measurements by a calibrated double-monochromator Brewer MK-III spectrophotometer at "El Arenosillo" station, located in southwestern Spain. Because the range of spectral measurements of the Brewer spectrophotometer is 290-363 nm, a previously validated radiative transfer model was used to account for the erythemal contribution between 363 and 400 nm. Both methods are recommended by the World Meteorological Organization and we present and discuss here a wide range of results and features given by modified procedures applied to these two general methods. As is well established, the calibration factor for this type of radiometric system is dependent on atmospheric conditions, the most important of which are the ozone content and the SZA. Although the first method is insensitive to these two factors, we analyze this behavior in terms of the range used for the SZA and the use of two different mathematical approaches for its determination. The second method shows the dependence on SZA and ozone content and, thus, a polynomial as a function of SZA or a matrix including SZA and ozone content were determined as general calibration factors for the UV radiometric system. We must note that the angular responses of the YES radiometer and Brewer spectroradiometer have not been considered, because of the difficulty in correcting them. The results show in detail the advantages and drawbacks (and the corresponding associated error) given by the different approaches used for the determination of these calibration coefficients.

Measured Solar Ultraviolet Radiation Exposures of Outdoor Workers in Queensland in the Building and Construction Industry¶

The risk to outdoor workers of exposure to solar ultraviolet radiation (UVR) has been known for some time, particularly in the building and construction industry, where workers often use little in the way of protection against solar UVR. In recent years there have been attempts by authorities in Australia and in Queensland in particular, where UVR levels in spring and summer are very high to extreme, to instigate and to encourage the use of personal UVR protection by outdoor workers. To quantify UVR exposure of building and construction industry workers involved in typical outdoor work, a study was conducted using UVR-sensitive polysulphone film badges. The results indicated that the doses were significant, often well in excess of recommended exposure limits. The measured exposures varied between trades. Data on the use of personal UVR-protective equipment and the skin type of workers were also collected. Many of the workers had skin types that were sensitive to UVR and showed signs of sunburn. In summary, the study found that at-risk individuals were exposed to extreme levels of UVR, in most cases without adequate and appropriate sun protection.