Levels Of Solar Ultraviolet Radiation Research Articles

Study of UV Index and Total Ozone Climatology Over Bhairahawa, Pokhara, and Lumle in Nepal

Recent studies on solar ultraviolet (UV) radiation have been pivotal in unveiling its detrimental impacts on humans and other living organisms on Earth. The Ultraviolet Index (UVI) is a crucial tool to ascertain the level of solar ultraviolet radiation at any given location, utilizing data from diverse sources. This study aims to examine the UV Index and Total Ozone Climatology over Bhairahawa (27.52°N, 83.43°E, 109m asl), Pokhara (28.22°N, 83.32°E, 850m asl), and Lumle (28.30°N, 83.80°E, 1740m asl), situated in the mid of Nepal, using OMI/Aura satellite data. The average minimum and maximum UV index recorded are 3.11±1.01 and 7.77±2.25 at Bhairahawa, 4.31±1.36 and 12.90±2.28 at Lumle, and 4.03±1.34 and 10.71±3.38 at Pokhara respectively. Additionally, the minimum Total Ozone Column (TOC) value is observed to be 251.4-288.5DU in December, with the maximum value reaching 291-285.3DU in April across all sites. This study concludes that the solar UV index increases with an increase in altitude, among other influential factors. The exploration of UVI and ozone data from the OMI/AURA satellite over specific locations in Nepal aims to enrich the existing pool of knowledge on solar ultraviolet radiation and its varying intensity, thereby contributing to the comprehension of its harmful implications on living entities.

The UV Index color palette revisited

The UV Index (UVI), standardized by the World Health Organization (WHO) in 2002, is an internationally accepted reference for disseminating information on solar UV radiation levels with the purpose of preventing the harmful effects on human health by sun overexposure. The UVI is the erythemal irradiance expressed in a dimensionless unit, with numerical values adapted to a risk scale that considers the “Extreme” level from a UVI value equal to 11 upwards. This scale is linked to a color palette by health risk ranges, and to a graded color palette by units of UVI for more details. Both the numerical scale and its associated risk levels were universally adopted by the scientific community and by global information systems to the population. However, inconsistencies and limitations persist between both UVI color palettes, making their interpretation and application difficult. In the present work all these aspects are addressed, proposing a revised color palette for unit UVI values that resolves each of them. Based on the WHO risk-ranges UVI color palette, the new color palette for unit UVI values gives coherence to both color charts, allowing reliable identification of the risk level bands and of each unit UVI level within them, and solves the need to distinguish between units for numerical values of UVI higher than 11 that are registered daily in many regions of the world.

The influence of meteorological factors on COVID-19 spread in Italy during the first and second wave

The relation between meteorological factors and COVID-19 spread remains uncertain, particularly with regard to the role of temperature, relative humidity and solar ultraviolet (UV) radiation. To assess this relation, we investigated disease spread within Italy during 2020. The pandemic had a large and early impact in Italy, and during 2020 the effects of vaccination and viral variants had not yet complicated the dynamics. We used non-linear, spline-based Poisson regression of modeled temperature, UV and relative humidity, adjusting for mobility patterns and additional confounders, to estimate daily rates of COVID-19 new cases, hospital and intensive care unit admissions, and deaths during the two waves of the pandemic in Italy during 2020. We found little association between relative humidity and COVID-19 endpoints in both waves, whereas UV radiation above 40 kJ/m2 showed a weak inverse association with hospital and ICU admissions in the first wave, and a stronger relation with all COVID-19 endpoints in the second wave. Temperature above 283 K (10 °C/50 °F) showed a strong non-linear negative relation with COVID-19 endpoints, with inconsistent relations below this cutpoint in the two waves. Given the biological plausibility of a relation between temperature and COVID-19, these data add support to the proposition that temperature above 283 K, and possibly high levels of solar UV radiation, reduced COVID-19 spread.

The GENESIS-UV study on ultraviolet radiation exposure levels in 250 occupations to foster epidemiological and legislative efforts to combat nonmelanoma skin cancer.

Several hundred million of the 3 billion formally employed people worldwide are at risk from high levels of solar ultraviolet radiation (UVR). Chronic light damage to the skin can lead to nonmelanoma skin cancer (NMSC), especially when irradiation is too high and is acquired for decades. However, data with uniform metrics, high resolution over time and in-depth occupational profiles are not available. To build a worldwide usable matrix of UVR exposure in occupations and to show use cases for the data. One thousand test persons were recruited to wear electronic data logger dosimeters during their working time for 7 months each. The measurements yielded 3.7 billion data points for around 48 000 days with high-quality data capture covering more than 250 occupations and 650 activities. Scientific evaluation of the data included daily and half-hourly means, geographical transfer calculations to the world, threshold exceedance quotas, transcriptome effects, and occupational disease estimates. A compendium for global use is presented. In-depth analyses and the resulting implications for research have been elaborated to directly link exposure data to effects in the human body. Interestingly, the annual irradiances of the different occupations span a wide range of values: from about 650 to 50 standard erythemal doses, with different distributions over the months. Detailed exposure data per occupation were derived, and the risk on an occupational or activity basis assuming different exposure level quotas was quantified. This showed that, for example, in temperate latitudes, all activities with a duration of > 2 h outdoors are associated with increased NMSC risk. We offer our work to enable sound studies on the nature of ultraviolet-induced skin cancer, dose-response relationships, intermittency of skin exposure, and derivation of limit values. Sociological studies on prevention are now possible. Practitioners may use the findings for their daily work with employees.

Different ways of estimating the amount of individual sun exposure.

Linked article:Souedi etal. Br J Dermatol 2022; 186:266-273. The sun is the main source of exposure people have to ultraviolet radiation (UVR). Sun exposure has some health benefits but also some adverse effects (for example sunburn and skin cancer). Studies about the link between UVR exposure and long-term health outcomes have used a number of different ways to try and accurately measure how much UVR individuals have been exposed to. We set out to study how accurate three different ways of measuring exposure to UVR were over 6 months: (1) ambient UVR levels, (2) self-reported time spent outdoors, and (3) a statistical formula. The participants in this study were employees who worked either indoors or outdoors in Catalunya - Spain during the summer and winter months. Using a wristwatch with a dosimeter (a device made specifically to measure solar UVR levels) we measured each of the participants UVR levels daily during their working hours. Using a statistical formula, we calculated the daily dose of solar UVR each participant received by including their measured levels (from the dosimeter), the general ambient UVR levels of that day, and self-reported time spent outdoors. We then compared the results. Of our 39 participants, not surprisingly, we noted that the levels of UVR were higher for outdoor workers and during the summer. We discovered that the calculated levels and the self-reported time spent outdoors (methods 2 and 3) were more accurate than measuring general ambient UVR levels (method 1) alone. These results will be helpful to researchers who are deciding which are the best methods to use in future studies about the health effects of UVR exposure.

Estimating personal solar ultraviolet radiation exposure through time spent outdoors, ambient levels and modelling approaches.

Evidence on validation of surrogates applied to evaluate the personal exposure levels of solar ultraviolet radiation (UVR) in epidemiological studies is scarce. To determine and compare the validity of three approaches, including (i) ambient UVR levels, (ii) time spent outdoors and (iii) a modelling approach integrating the aforementioned parameters, to estimate personal UVR exposure over a period of 6 months among indoor and outdoor workers and in different seasons (summer/winter). This validation study was part of the European Commission-funded ICEPURE project and was performed between July 2010 and January 2011 in a convenience sample of indoor and outdoor workers in Catalunya, Spain. We developed linear regression models to quantify the variation in the objectively measured personal UVR exposure that could be explained, separately, by the ambient UVR, time spent outdoors and modelled UVR levels. Our 39 participants - mostly male and with a median age of 35 years - presented a median daily objectively measured UVR of 0·37 standard erythemal doses. The UVR dose was statistically significantly higher in summer and for outdoor workers. The modelled personal UVR exposure and self-reported time spent outdoors could reasonably predict the variation in the objectively measured personal UVR levels (R2 range 0·75-0·79), whereas ambient UVR was a poor predictor (R2 = 0·21). No notable differences were found between seasons or occupation. Time outdoors and our modelling approach were reliable predictors and of value to be applied in epidemiological studies of the health effects of current exposure to UVR.

Erythemal ultraviolet radiation exposure of high school rowers in Aotearoa/New Zealand.

Athletes who compete in outdoor sports can receive potentially harmful levels of solar ultraviolet radiation (UVR). Rowing is a popular outdoor sport that takes place during the peak UVR season. Using electronic dosimeters attached to the shoulder strap of the rower's uniform, this study aimed to quantify the real-time solar UVR exposure experienced by high school rowers during competition. We measured personal UVR exposure (PE) during the time spent on the water in order to compete in a single rowing-race (race-time), when rowing administrators are responsible for athletes' wellbeing. Data collection took place in Aotearoa (New Zealand) at Lake Ruataniwha (44.28°S, 170.07°E), during two consecutive rowing seasons (December-February 2018-19 and 2019-20). Analysis of dosimeter data generated from 56 race-times over five regattas revealed a median personal UVR exposure (PE) of 1.15 standard erythemal dose (SED), where 1 SED is defined as an effective radiant exposure of 100 Jm-2. Mean race-time was 46min. Over two-thirds of race-times (69.6%) exceeded the Australian Radiation Protection and Nuclear Safety Agency recommendation of 1 SED being considered safe for most people in a day. An exposure of 1.5-3.0 SED produces perceptible erythema for people with light coloured skin and the lower parameter of 1.5 SED was exceeded in 14 (25.0%) of the race-times. By regatta, the median SED/h ranged from 0.96-2.40 and the median percentage of total concurrent ambient UVR ranged from 17 to 31%. Our results indicate that rowing is a high UVR sport and that races outside of peak UVR times also warrant the use of sun protection even when the UVI<3. Given that acute and cumulative UVR exposure are recognised risk factors in the development of ocular diseases and skin cancers later in life, risk management guidelines for competitive school rowing will be incomplete until a long-term approach to well-being is considered and comprehensive sun protection measures adopted.

UV Index for Public Health Awareness Based on OMI/NASA Satellite Data at King Abdulaziz University, Saudi Arabia

Exposure to ultraviolet radiation (UV) is essential for good health and formation of vitamin D while overexposure poses a risk to public health. Therefore, it is important to provide information to the public about the level of solar UV radiation. The ultraviolet index (UVI) is used to help avoid the negative effects of ultraviolet (UV) radiation on humans and to optimize individual exposure. There is limited ground measurement of solar UV radiation, but satellite Ozone Monitoring Instrument (OMIs) satellite products with a spatial resolution of 1 ° × 1 ° can be used to create UV index climatology at local noon time. In this study, we utilize OMI satellite products collected over the campus of King Abdulaziz University (KAU) (21.5° North and 39.1° East), Jeddah, Saudi Arabia, to estimate changes in exposure to UV over a period of 15 years (2004-2020). The results indicate a significantly increasing trend in UV index over this period. Between 2004 and 2020, daily “extreme” UV ( UVI &gt; 11 , as defined by the World Health Organization (WHO)) occurred on 46.60% of days. The frequency of low UVI ( UVI &lt; 2 ) was only about 0.06%. These results imply dangerous exposure levels to solar UV radiation on the KAU campus and call for safety measures to increase awareness and decrease direct exposure; for example, by implementing the United States Environmental Protection Agency (EPA) general guidelines.

Personal Solar Ultraviolet Radiation Exposure of Farmworkers: Seasonal and Anatomical Differences Suggest Prevention Measures Are Required.

Farmworkers are at risk of excess exposure to solar ultraviolet radiation (UVR) during their work activities, especially if they work in geographical areas with high ambient solar UVR levels such as in South Africa. Excess exposure to solar UVR may lead to several negative health effects such as certain cataracts and skin cancer. This study evaluated personal solar UVR exposure of a group of farmworkers to determine if they were at risk of health-related problems due to excess solar UVR exposure. Polysulphone film (PSF) badges were placed on the shoulder, arm, and top of the head of outdoor and indoor farmworkers on a macadamia nut and avocado farm in the Limpopo province for the duration of their daily work shift to evaluate their total daily solar UVR exposure. Sixteen days were assessed for each of the three, high solar UVR seasons, i.e. autumn, spring, and summer. During autumn, farmworkers' arms received the highest solar UVR exposures (geometric mean (GM) = 7.8 SED, where 1 standard erythemal dose (SED) = 100 J/m2, 95% CI 6.1-9.8 SED) while the highest exposures were on the top of the head during spring (GM = 11.6 SED, 95% CI 7.3-17.4 SED) and summer (GM = 13.9, 95% CI 10.4-17.9 SED). Statistically significant differences in solar UVR exposure were found between the body sites during spring and summer but not autumn. The relatively high daily solar UVR exposure levels of farmworkers suggest this occupational group is at risk of excess solar UVR exposure and preventive measures with awareness information to safeguard health is necessary for employers and employees.

Health Risks Associated With Excessive Exposure to Solar Ultraviolet Radiation Among Outdoor Workers in South Africa: An Overview.

Exposure of outdoor workers to high levels of solar ultraviolet radiation (UVR) poses significant, well-known health risks including skin cancer and eye diseases. In South Africa, little is known about how many workers are potentially overexposed to solar UVR and what the associated impacts on their health might be. In this overview, the geography and solar UVR environment in South Africa are considered, as well as the different outdoor occupational groups likely to be affected by excessive solar UVR exposure. Sunburn, pterygium, cataract, keratinocyte cancers, and melanoma are discussed in the context of outdoor workers. Few studies in South Africa have considered these health issues and the most effective ways to reduce solar UVR exposure for those working outside. Several countries have developed policies and guidelines to support sun safety in the workplace which include training and education, in addition to the provision of personal protective equipment and managerial support. Several gaps in occupational sun protection and workplace sun safety for South Africa are identified. Legislation needs to recognize solar UVR exposure as an occupational health hazard, with sun safety guidelines and training provided for employers and employees.

Ultraviolet Radiation Stimulates Activity of CO2 Concentrating Mechanisms in a Bloom-Forming Diatom Under Reduced CO2 Availability.

The diatom Skeletonema costatum is cosmopolitan and forms algal blooms in coastal waters, being exposed to varying levels of solar UV radiation (UVR) and reduced levels of carbon dioxide (CO2). While reduced CO2 availability is known to enhance CO2 concentrating mechanisms (CCMs) in this diatom and others, little is known on the effects of UV on microalgal CCMs, especially when CO2 levels fluctuate in coastal waters. Here, we show that S. costatum upregulated its CCMs in response to UVR (295–395 nm), especially to UVA (320–395 nm) in the presence and absence of photosynthetically active radiation (PAR). The intensity rise of UVA and/or UVR alone resulted in an increase of the activity of extracellular carbonic anhydrase (CAe); and the addition of UVA enhanced the activity of CCMs-related CAe by 23–27% when PAR levels were low. Such UV-stimulated CCMs activity was only significant at the reduced CO2 level (3.4 μmol L−1). In addition, UVA alone drove active HCO3− uptake although it was not as obvious as CAe activity, another evidence for its role in enhancing CCMs activity. In parallel, the addition of UVA enhanced photosynthetic carbon fixation only at the lower CO2 level compared to PAR alone. In the absence of PAR, carbon fixation increased linearly with increased intensities of UVA or UVR regardless of the CO2 levels. These findings imply that during S. costatum blooming period when CO2 and PAR availability becomes lower, solar UVR (mainly UVA) helps to upregulate its CCMs and thus carbon fixation, enabling its success of frequent algal blooms.

A One-Month Monitoring of Exposure to Solar UV Radiation of a Group of Construction Workers in Tuscany

Solar radiation exposure at work is a relevant heath risk in the construction sector. Our objective was to monitor for a full month the individual solar ultraviolet radiation (UVR) exposure of a group of three construction workers active in Siena (latitude = 43°19′ N), a town in Tuscany (Italy). We used personal electronic dosimeters “X-2012-10” (Gigahertz, Turkenfeld, Germany) to register the UV irradiance in the UVA and UVB/C regions separately and we consulted a specific database to retrieve the corresponding ambient erythemal UVR dose (cloud-free conditions). In spring, construction workers from central Italy received a quite variable UVR dose, between 0.9 standard erythemal doses (SED) and 15.6 SED/day, 5.7 on average. Considering the proportion with respect to the potential environmental exposure, personal exposure resulted between 2.7% and 31.2% of the ambient erythemal dose, with a mean value of 12.5%. Cumulatively, the three construction workers received in one working month a UVR dose of more than 120 SED. In a year, we estimated that a construction worker from Tuscany region is exposed to about 750 SED. This data demonstrates that construction workers in Italy are exposed to extremely high levels of solar UVR, with a relevant risk of developing adverse health effects related to the potential accumulation of UVR-induced damage in susceptible biological tissues, such as the skin and the eyes.

Solar UV Radiation in the Tropics: Human Exposure at Reunion Island (21° S, 55° E) during Summer Outdoor Activities.

Reunion Island is a popular tourist destination with sandy beaches, an active volcano (Piton de la Fournaise), and Piton des Neiges, the highest and most dominant geological feature on the island. Reunion is known to have high levels of solar ultraviolet radiation (UVR) with an ultraviolet index (UVI) which can reach 8 in winter and 16 in summer (climatological conditions). UVR has been linked to skin cancer, melanoma, and eye disease such as cataracts. The World Health Organization (WHO) devised the UVI as a tool for expressing UVR intensity. Thresholds ranging from low (UVI 1–2) to extreme (UVI > 11) were defined depending on the risk to human health. The purpose of the study was to assess UVR exposure levels over three of the busiest tourist sites on the island. UVR was measured over several hours along popular hiking trails around Piton de la Fournaise (PDF), Piton des Neiges (PDN), and St-Leu Beach (LEU). The results were compared with those recorded by the local UV station at Saint-Denis. In addition, cumulative standard erythemal dose (SED) was calculated. Results showed that UVI exposure at PDF, PDN, and LEU were extreme (>11) and reached maximum UVI levels of 21.1, 22.5, and 14.5, respectively. Cumulative SEDs were multiple times higher than the thresholds established by the Fitzpatrick skin phototype classification. UVI measurements at the three study sites showed that Reunion Island is exposed to extreme UVR conditions. Public awareness campaigns are needed to inform the population of the health risks related to UVR exposure.

Solar ultraviolet radiation exposure among outdoor workers in Alberta, Canada

BackgroundOutdoor workers are at risk of prolonged and high solar ultraviolet radiation (UVR) exposure, which is known to cause skin cancer. The objectives of this study were to characterize the UVR exposure levels of outdoor workers in Alberta, Canada, and to investigate what factors may contribute to their exposure. MethodsThis study collected objective solar UVR measurements from outdoor workers primarily in Alberta during the summer of 2019. Workers were recruited via the management or health and safety teams from building trade unions and employers. Calibrated, electronic UVR dosimeters were worn by workers on their hardhats, wrists, or lapels for five working days. Data on workers’ demographics, jobs, sun protection behaviors, and personal risk factors were collected using questionnaires, and meteorological data for each sampling day were noted. Mean daily exposure measured as the standard erythemal dose (SED) was calculated and compared to the international occupational exposure limit guideline (1.3 SED). Marginal models were developed to evaluate potential determinants of occupational solar UVR exposure. ResultsIn total, 883 measurements were collected from 179 workers. On average, workerswere exposed to 1.93 SED (range: 0.03–16.63 SED) per day. Just under half of workers (45%) were exposed to levels exceeding the international exposure limit guideline. In the bivariate analyses, landscape and maintenance workers, as well as trade and recreation workers, had the highest levels of exposure (average: 2.64 and 1.84 SED, respectively). Regional variations were observed, with the “other” cities/regions (outside of Edmonton and Calgary) experiencing the highest average levels (2.60 SED). Workers who placed the dosimeters on their hardhats experienced higher levels compared to the other groups. Exposure was highest on sunny and mixed days. Education, trade, city, dosimeter placement, forecast, hair colour, and number of hours outside were included in the final exposure model, of which trade, dosimeter placement, forecast, and number of hours outside at work were statistically significant. ConclusionsExposure to elevated solar UVR levels is common among outdoor workers in Alberta. The study findings can help inform future monitoring studies and exposure reduction initiatives aimed at protecting workers.

SunSmart Accreditation and Use of a Professional Policy Drafting Service: Both Positively and Independently Associated with High Sun Protective Hat Scores Derived from Primary School Policies.

Background The head and neck are exposed to the highest solar ultraviolet radiation levels and experience a disproportionate skin cancer burden. Sun protective hats can provide an effective barrier. Since early life exposure contributes to skin cancer risk, the World Health Organisation recommends prevention programmes in schools. The New Zealand SunSmart Schools programme is one example. Two criteria concern wearing hat outdoors: students are required to wear a hat providing protection for the face, neck, and ears; if a suitable hat is not worn, students must play in shaded areas. Objectives To investigate two internationally relevant interventions as plausible statistical predictors of hat policy strength: (1) skin cancer primary prevention programme membership, (2) use of a professional policy drafting service. Methods Of 1,242 (62%) eligible schools participating in a 2017 national survey, 1,137 reported a sun protection policy and 842 were available for categorising and allocating protective scores (0–3). Results In multinomial (polytomous) logistic regression models of cross-sectional association, adjusted for school characteristics, SunSmart accredited schools and those utilising a policy drafting service were independently significantly more likely than their counterparts to obtain the most protective compared to the least protective hat score (respectively, RRR 6.48: 95% CI 3.66, 11.47; 7.47: 3.67, and 15.20). For the dichotomous shade measure, similar associations were found using adjusted logistic regression (OR 3.28: 95% CI 2.11, 5.09; 2.70: 1.54, 4.74). Conclusions Our findings provide support for two plausible interventions that could potentially be implemented beneficially in primary schools via established infrastructure in any jurisdiction, internationally.

Giant clams in shallow reefs: UV-resistance mechanisms of Tridacninae in the Red Sea

The photosymbiosis of tropical giant clams (subfamily Tridacninae) with unicellular algae (Symbiodiniaceae) restricts their distribution to the sunlit, shallow waters of the euphotic zone where organisms are additionally exposed to potentially damaging levels of solar UV radiation. Metabolic and physiological responses of Red Sea Tridacna maxima clams, including net calcification and primary production, as well as valvometry (i.e., shell gaping behavior) were assessed when exposed to simulated high radiation levels received at 3 and 5 m underwater. The two levels of radiation included exposure treatments to photosynthetically active radiation (PAR; 400–700 nm) alone and to both, PAR and ultraviolet-B radiation (UV-B; 280–315 nm). The valvometry data obtained using flexible magnetic sensors indicated that specimens under PAR + UV-B exposure significantly reduced the proportion of their exposed mantle area, a potential photo-protective mechanism which, however, reduces the overall amount of PAR received by the algal symbionts. Consequently, specimens under PAR + UV-B displayed a slight, although non-significant, reduction in primary production rates but no signs of additional oxidative stress, changes in symbiont densities, chlorophyll content, or levels of mycosporine-like amino acids. Net calcification rates of T. maxima were not affected by exposure to UV-B; however, calcification was positively correlated with incident PAR levels. UV-B exposure changes the valvometry, reducing the exposed mantle area which consequently diminishes the available PAR for the photosymbionts. Still, T. maxima maintains high rates of primary production and net calcification, even under high levels of UV-B. This provides experimental support for a recently described, effective UV-defensive mechanism in Tridacninae, in which the photonic cooperation of the associated algal symbionts and giant clam iridocytes is assumed to establish optimal conditions for the photosynthetic performance of the clams’ symbionts.

The Epidemiology of Skin Cancer and Public Health Strategies for Its Prevention in Southern Africa.

Skin cancer is a non-communicable disease that has been underexplored in Africa, including Southern Africa. Exposure to solar ultraviolet radiation (UVR) is an important, potentially modifiable risk factor for skin cancer. The countries which comprise Southern Africa are Botswana, Lesotho, Namibia, South Africa, and Swaziland. They differ in population size and composition and experience different levels of solar UVR. Here, the epidemiology and prevalence of skin cancer in Southern African countries are outlined. Information is provided on skin cancer prevention campaigns in these countries, and evidence sought to support recommendations for skin cancer prevention, especially for people with fair skin, or oculocutaneous albinism or HIV-AIDS who are at the greatest risk. Consideration is given to the possible impacts of climate change on skin cancer in Southern Africa and the need for adaptation and human behavioural change is emphasized.

The Early Days of Personal Solar Ultraviolet Dosimetry

In the early 1970s, environmental conservationists were becoming concerned that a reduction in the thickness of the atmospheric ozone layer would lead to increased levels of ultraviolet (UV) radiation at ground level, resulting in higher population exposure to UV and subsequent harm, especially a rise in skin cancer. At the time, no measurements had been reported on the normal levels of solar UV radiation which populations received in their usual environment, so this lack of data, coupled with increasing concerns about the impact to human health, led to the development of simple devices that monitored personal UV exposure. The first and most widely used UV dosimeter was the polymer film, polysulphone, and this review describes its properties and some of the pioneering studies using the dosimeter that led to a quantitative understanding of human exposure to sunlight in a variety of behavioral, occupational, and geographical settings.

Ultraviolet A-induced hematotoxic and genotoxic potential in Nile tilapia Oreochromis niloticus.

Fish as an aquatic organism could be harmed by various levels of solar ultraviolet radiation (UVA). The present study aimed to characterize UVA (20, 60 and 180 min for 3 days) irradiation-induced hematological and biochemical changes in Oreochromis niloticus. Hematological parameters such as the red blood cell (RBC) count, hemoglobin (Hb) level and hematocrit (Hct) value were significantly (p < 0.05) reduced in fish exposed to different doses of UVA. Also, the leukocyte (WBC) count was significantly reduced (p < 0.05). However, the differential counts of WBCs - lymphocytes, eosinophils and monocytes - increased significantly in the exposed fish compared to the control fish. Many morphological and genotoxic alterations in erythrocytes were observed in the present work. The glucose level showed a significant decrease, but cholesterol and triglycerides showed a significant increase after exposure to UVA. Total protein levels of the fish showed a significant increase (p < 0.05) in the exposed groups. Also, concentrations of urea and creatinine increased significantly as fish were exposed to increasing UVA radiation, compared to the control fish. Finally, the activities of alanine aminotransferase (ALT, U l-1) and aspartate aminotransferase (AST, U l-1) exhibited a significant increase (p < 0.05) with increasing UVA doses.

Spring and summer time ozone and solar ultraviolet radiation variations over Cape Point, South Africa

Abstract. The correlation between solar ultraviolet radiation (UV) and atmospheric ozone is well understood. Decreased stratospheric ozone levels which led to increased solar UV radiation levels at the surface have been recorded. These increased levels of solar UV radiation have potential negative impacts on public health. This study was done to determine whether the break-up of the Antarctic ozone hole has an impact on stratospheric columnar ozone (SCO) and resulting ambient solar UV-B radiation levels at Cape Point, South Africa, over 2007–2016. We investigated the correlations between UV index, calculated from ground-based solar UV-B radiation measurements and satellite-retrieved column ozone data. The strongest anti-correlation on clear-sky days was found at solar zenith angle 25∘ with exponential fit R2 values of 0.45 and 0.53 for total ozone column and SCO, respectively. An average radiation amplification factor of 0.59 across all SZAs was calculated for clear-sky days. The MIMOSA-CHIM model showed that the polar vortex had a limited effect on ozone levels. Tropical air masses more frequently affect the study site, and this requires further investigation.