Effects Of Solar Ultraviolet Radiation Research Articles

The adverse consequences of not using sunscreens.

The adverse effects of solar ultraviolet radiation (UVR) on normal skin are well established, especially in those with poorly melanized skin. Clinically, these effects may be classified as acute, such as erythema or chronic such as keratinocyte and melanocyte skin cancers. Apart from skin type genetics, clinical responses to solar UVR are dependent on geophysical (e.g., solar intensity) and behavioural factors. The latter are especially important because they may result in 'solar overload' with unwanted clinical consequences and ever greater burdens to healthcare systems. Correctly used, sunscreens can mitigate the acute and chronic effects of solar UVR exposure. Laboratory studies also show that sunscreens can inhibit the initial molecular and cellular events that are responsible for clinical outcomes. Despite public health campaigns, global trends continue to show increasing incidence of all types of skin cancer. Large-scale epidemiological studies have shown the benefits of sunscreen use in preventing skin cancer, though it is likely that sunscreen use has not been optimal in such studies. It is evident that without substantial changes in sun-seeking behaviour, sunscreen use is a very important part of the defence against the acute and chronic effects of solar exposure. Ideally, sunscreens should be able to provide the level of protection that reduces the risk of skin cancer in susceptible skin types to that observed in heavily melanized skin.

Effects of UV radiation on natural and synthetic materials

The deleterious effects of solar ultraviolet (UV) radiation on construction materials, especially wood and plastics, and the consequent impacts on their useful lifetimes, are well documented in scientific literature. Any future increase in solar UV radiation and ambient temperature due to climate change will therefore shorten service lifetimes of materials, which will require higher levels of stabilisation or other interventions to maintain their lifetimes at the present levels. The implementation of the Montreal Protocol and its amendments on substances that deplete the ozone layer, controls the solar UV-B radiation received on Earth. This current quadrennial assessment provides a comprehensive update on the deleterious effects of solar UV radiation on the durability of natural and synthetic materials, as well as recent innovations in better stabilising of materials against solar UV radiation-induced damage. Pertinent emerging technologies for wood and plastics used in construction, composite materials used in construction, textile fibres, comfort fabric, and photovoltaic materials, are addressed in detail. Also addressed are the trends in technology designed to increase sustainability via replacing toxic, unsustainable, legacy additives with ‘greener’ benign substitutes that may indirectly affect the UV stability of the redesigned materials. An emerging class of efficient photostabilisers are the nanoscale particles that include oxide fillers and nanocarbons used in high-performance composites, which provide good UV stability to materials. They also allow the design of UV-shielding fabric materials with impressive UV protection factors. An emerging environmental issue related to the photodegradation of plastics is the generation of ubiquitous micro-scale particles from plastic litter exposed to solar UV radiation.Graphical abstract

Erythemal UV radiation across Nigeria: where do we stand?

The deleterious effects of solar ultraviolet (UV) radiation on humans are of public health concern which demands constant global monitoring and intervention. This study analysed the latitudinal variations in mean daily and multi-year erythemal ultraviolet radiation (EUVR) across 7 states in Nigeria using satellite data from the Total Ozone Mapping Spectrophotometer (TOMS) and Ozone Mapping Instrument (OMI). The latitudes studied were 13° N, 8° N, 6° N and 4° N respectively, using 37 years of data obtained from phases: 1979–1988, 1989–1998, 1999–2008 and 2009–2020. The data obtained were statistically analysed using Ms Excel and MATLAB. The results of this study show that the mean daily EUVR at the selected latitudes ranges from 32.97 to 390 (mW/m2). The results show that Borno State located at latitude 13° N had the highest EUVR, while Rivers State recorded the least EUVR at latitude 4° N. Comparative analysis of all the locations studied indicates latitudinal and longitudinal variations because the eastern axis recorded higher values than its western counterpart on the same latitude. Box and whisker plots in this study summarized the latitudinal variance in the mean multi-year EUVR in each phase. Box and whisker plots from 2009–2020 showed that there was a drastic reduction in mean multi-year EUVR in this phase unlike in the other phases. The findings of this study when compared to the UV index show that the 37 years mean EUVR obtained across Nigeria ranged from 8–10 which is on the “very high” category. This study recommends the implementation of WHO suggestions in preventing the biological effects of solar UV radiation. Furthermore, the Nigerian government should curb ignorance among its citizens by heightening public awareness of the effects of EUVR.

Clean agricultural production by solar water disinfection in hydroponic systems using synergistic effects

Disinfecting and reusing water is a proper method for decreasing chemical control and water consumption. The sun was selected for disinfection as a free, clean, available, and sustainable source with disinfectant effects. Most solar collectors use heat or ultraviolet separately for disinfection. This research is aimed to simultaneously apply heat and solar ultraviolet radiation to profit synergistic effect by combining vacuum tubes and a flat-plate solar collector. In the first stage, the synergistic effect between solar ultraviolet radiation and water temperature on the viability of hydroponic pathogens was measured. Then, the temperature distribution in the collector reservoir was studied using a computational fluid dynamics (CFD) simulation to survey temperature uniformity. An average collector thermal efficiency of 58.66% was obtained. The simultaneous effect of solar ultraviolet radiation and the temperature of 50 ℃ showed a significant reduction of disinfection time rather than only temperature (fungi 5 to 2 h), and the necessary solar ultraviolet dose for inactivating fungi was determined as 136.775 kJ m−2. Although the presented solar collector was examined for hydroponic systems, it can be used for other applications such as drinking water disinfection.

NRF2 and Key Transcriptional Targets in Melanoma Redox Manipulation.

Simple SummaryMelanocytes are the pigment-producing cells in the skin that help to protect it against damaging solar ultraviolet radiation. As they engage in this function, they are subject to an inordinate amount of oxidative stress. To protect themselves, they utilize numerous antioxidant systems to reduce the amount of reactive oxygen and nitrogen species present in the cells, and this activity then contributes towards the prevention of cancer formation. However, after the formation of melanomas these same antioxidant systems are often co-opted by the cancer in order to promote its uncontrolled growth and metastasis. The purpose of this review is to highlight how the melanocyte’s antioxidant systems, regulated by the transcription factor NRF2 and its targets, are co-opted in melanomas and, therefore, could be targeted for novel therapies to treat melanomas going forward.Melanocytes are dendritic, pigment-producing cells located in the skin and are responsible for its protection against the deleterious effects of solar ultraviolet radiation (UVR), which include DNA damage and elevated reactive oxygen species (ROS). They do so by synthesizing photoprotective melanin pigments and distributing them to adjacent skin cells (e.g., keratinocytes). However, melanocytes encounter a large burden of oxidative stress during this process, due to both exogenous and endogenous sources. Therefore, melanocytes employ numerous antioxidant defenses to protect themselves; these are largely regulated by the master stress response transcription factor, nuclear factor erythroid 2-related factor 2 (NRF2). Key effector transcriptional targets of NRF2 include the components of the glutathione and thioredoxin antioxidant systems. Despite these defenses, melanocyte DNA often is subject to mutations that result in the dysregulation of the proliferative mitogen-activated protein kinase (MAPK) pathway and the cell cycle. Following tumor initiation, endogenous antioxidant systems are co-opted, a consequence of elevated oxidative stress caused by metabolic reprogramming, to establish an altered redox homeostasis. This altered redox homeostasis contributes to tumor progression and metastasis, while also complicating the application of exogenous antioxidant treatments. Further understanding of melanocyte redox homeostasis, in the presence or absence of disease, would contribute to the development of novel therapies to aid in the prevention and treatment of melanomas and other skin diseases

Removing Plant Pathogenic Bacteria by Solar Ultraviolet Radiation in Hydroponic Systems

Removing plant pathogens with the sun as a free, available, clean, and sustainable source of energy is interesting. However, there is no data for disinfecting major plant pathogenic bacteria such as Pseudomonas syringae and Clavibacter michiganensis subsp. michiganensis by solar ultraviolet radiation. To obtain the required time for killing these bacteria at different temperatures, a bacterial suspension of active growing cells (approximately 107 CFU mL-1) was prepared and subjected to heat inside a water bath. The minimum required time for killing both of the bacteria was achieved 420, 45, and 15 min at 50, 55, and 60 °C, respectively. To examine the effect of solar ultraviolet radiation, the bacteria suspensions inside a quartz tube were exposed to the sun on a horizontal surface at the constant temperature of 50 °C within the water bath (water depth: 0.1 m). Both of the bacteria were killed after one hour by receiving 95.481 kJ m-2 ultraviolet and 2.79315 MJ m-2 solar radiation doses. The synergy of heat and solar UV could considerably reduce the killing time of the bacteria (7 to 1 hours) at 50 °C. The recommended solar UV dose is 95.481 kJ m-2 for this condition.

Participation of keratinocyte- and fibroblast-derived factors in melanocyte homeostasis, the response to UV, and pigmentary disorders.

Human epidermal melanocytes play a central role in sensing the environment and protecting the skin from the drastic effects of solar ultraviolet radiation and other environmental toxins or inflammatory agents. Melanocytes survive in the epidermis for decades, which subjects them to chronic environmental insults. Melanocytes have a poor self-renewal capacity; therefore, it is critical to ensure their survival with genomic stability. The function and survival of melanocytes is regulated by an elaborate network of paracrine factors synthesized mainly by epidermal keratinocytes and dermal fibroblasts. A symbiotic relationship exists between epidermal melanocytes and keratinocytes on the one hand, and between melanocytes and dermal fibroblasts on the other hand. Melanocytes protect epidermal keratinocytes and dermal fibroblasts from the damaging effects of solar radiation, and the latter cells synthesize biochemical mediators that maintain the homeostasis, and regulate the stress response of melanocytes. Disruption of the paracrine network results in pigmentary disorders, due to abnormal regulation of melanin synthesis, and compromise of melanocyte survival or genomic stability. This review provides an update of the current knowledge of keratinocyte- and fibroblast-derived paracrine factors and their contribution to melanocyte physiology, and how their abnormal production is involved in the pathogenesis of common pigmentary disorders.

Solar ultraviolet radiation sensitivity of SARS-CoV-2

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), can be life-threatening; the outbreak of this disease was characterised as a pandemic by WHO on March 11, 2020.1 COVID-19 is currently a global health issue and governments are taking a series of measures to reduce the spread of the virus among communities. Factors affecting the survival of SARS-CoV-2 need to be clarified and the effect of solar ultraviolet radiation is one subject under discussion.

Phenolic characteristics acquired by berry skins of Vitis vinifera cv. Tempranillo in response to close-to-ambient solar ultraviolet radiation are mostly reflected in the resulting wines.

It is widely recognized that ambient levels of solar ultraviolet (UV) radiation strongly influence the phenolic composition of grape skins. However, it is unknown to what extent this influence is reflected in the resulting wines. Tempranillo grapevines were exposed or non-exposed to close-to-ambient solar UV levels using appropriate filters, and the phenolic profiles and antioxidant capacity of both grape skins and the resulting wines were analyzed. In total, 47 phenolic compounds were identified in skins and wines, including flavonols, anthocyanins, flavanols, stilbenes, and hydroxycinnamic and hydroxybenzoic acids. In UV-exposed grape skins, flavonols and anthocyanins increased, whereas flavanols and hydroxybenzoic acids showed no significant change. These characteristics were conserved in the resulting wines. However, for stilbenes, hydroxycinnamic acids and antioxidant capacity, the effect of UV on grape skins was not conserved in wines, probably as a result of changes during winemaking. In addition, color intensity, total phenols and total polyphenol index of wines elaborated from UV-exposed grapes increased (although non-significantly) compared to those made from non-UV-exposed grapes. The phenolic composition of grape skins exposed to close-to-ambient solar UV could predict, to some extent, the phenolic composition of the resulting wines, particularly regarding higher contents of flavonols and anthocyanins. Thus, manipulating the UV radiation received by grape skins could improve wine quality by positively influencing color stability and healthy properties. To our knowledge, this is the first study in which the effects of solar UV radiation on phenolic composition have been assessed from grape skins to wine. © 2019 Society of Chemical Industry.

Effect of UV-B radiations on mortality and enzymes level in fish larvae of Tor tor and Schizothorax richardsonii on laboratory scale

Depletion of stratospheric ozone layer is resulting into increase in solar UV-B on earth surface. Ultra violet radiation is well known to cause many detrimental effects in aquatic organisms. The present study was performed to study the effect of solar ultraviolet radiation on fish fingerlings of Tor tor and Schizothorax richardsonii as a model system on laboratory scale. The effect of different intensities of natural solar and artificial UV-B radiation on fish larvae of T. tor and S. richardsonii in a presence of retene was investigated. Solar ultraviolet intensity showed seasonal and altitudinal variations in Garhwal region. Solar UV radiation level was lower (0.390 mw/cm2) in the month of January- February at lower altitude and highest (1.192 mw/cm2) in the month of July-August 2018 at higher altitude. Fish larvae exposed to artificial UV-B (average wavelength 312 nm and intensity of 750 mw/cm2) with retene (50µg/l) showed increase in gills malandialdehyde level and caused larvae mortality as indicating that enhanced solar UV-B exposure could be lethal to fish fauna in aquatic ecosystem. Artificial UV-B had a stronger damaging effect on fish larvae than solar radiation exhibited highly toxic in presence of retene. The larvae of S. richardsonii was found more sensitive than T. tor as indicated by high mortality rate (30%) and high pigmented characteristics on dorsal side. The solar and ultraviolet radiation showed a positive effect on high pigmentation. These results suggest that on a short time scale, UV-B radiation causing developmental stress on fish larvae may contribute to assess the phototoxic behaviour of cold water fishes.

MC1R: Front and Center in the Bright Side of Dark Eumelanin and DNA Repair.

Melanin, the pigment produced by specialized cells, melanocytes, is responsible for skin and hair color. Skin pigmentation is an important protective mechanism against the DNA damaging and mutagenic effects of solar ultraviolet radiation (UV). It is acknowledged that exposure to UV is the main etiological environmental factor for all forms of skin cancer, including melanoma. DNA repair capacity is another major factor that determines the risk for skin cancer. Human melanocytes synthesize eumelanin, the dark brown form of melanin, as well as pheomelanin, which is reddish-yellow in color. The relative rates of eumelanin and pheomelanin synthesis by melanocytes determine skin color and the sensitivity of skin to the drastic effects of solar UV. Understanding the complex regulation of melanocyte function and how it responds to solar UV has a huge impact on developing novel photoprotective strategies to prevent skin cancer, particularly melanoma, the most fatal form, which originates from melanocytes. This review provides an overview of the known differences in the photoprotective effects of eumelanin versus pheomelanin, how these two forms of melanin are regulated genetically and biochemically, and their impact on the DNA damaging effects of UV exposure. Additionally, this review briefly discusses the role of paracrine factors, focusing on α-melanocortin (α-melanocyte stimulating hormone; α-MSH), in regulating melanogenesis and the response of melanocytes to UV, and describes a chemoprevention strategy based on targeting the melanocortin 1 receptor (MC1R) by analogs of its physiological agonist α-MSH.

Sunlight-induced genotoxicity and damage in keratin structures decrease tadpole performance

The increased incidence of solar ultraviolet (UV) radiation, an environmental genotoxic agent, due to ozone depletion or deforestation may help to explain the enigmatic decline of amphibian populations in specific localities. In this work, we evaluated the importance of DNA repair performed by photolyases to maintain the performance of treefrog tadpoles after acute and chronic treatments with environmental-simulated doses of solar UVB and UVA radiation. Immediately after UV treatments, tadpoles were exposed to a visible light source to activate photolyases or kept in dark containers. The biological effects of UV treatments were evaluated through morphological, histological, locomotor and survival analyzes of Boana pulchella tadpoles (Anura: Hylidae). The results indicate that tadpole body weight suffered influence after both UVB and UVA treatments, although the body length was bit affected. The locomotor performance of UVB-exposed tadpoles was significantly reduced. In addition, UVB radiation induced a severe impact on tadpole skin, as well as on keratinized structures of mouth (tooth rows and jaw), indicating that these should be important effects of solar UV radiation in the reduction of tadpole performance. Furthermore, photolyases activation was fundamental for the maintenance of tadpole performance after chronic UVB exposures, but it was relatively inefficient after acute exposures to UVB, but not to UVA radiation. Therefore, this work demonstrates how the UV-induced genotoxicity and structural alterations in the skin and oral apparatus affect tadpole performance and survival.

Mycosporine-Like Amino Acids (MAAs) Profile of Two Marine Red Macroalgae, Gelidium sp. and Ceramium sp.

Macroalgae have evolved different strategies to mitigate the damaging effects of solar ultraviolet radiation (UVR), including accumulation of photoprotective compounds such as mycosporine-like amino acids (MAAs). MAAs are secondary metabolites, synthesized by a large variety of organisms including macroalgae, phytoplanktons, cyanobacteria, lichen, fungi and some marine animals. MAAs act as photoprotectants and antioxidants. In the present investigation, MAAs profile of methanolic extracts of two marine red algae Gelidium sp. and Ceramium sp., collected from their natural environment, was studied. High-performance liquid chromatography (HPLC) and UV-Vis spectrometry analyses were used to reveal different MAAs profile in the extracts obtained from these two red algae. The MAAs isolated by HPLC were identified as shinorine (λmax= 333.5 nm), porphyra-334 (λmax=332.3 nm) and palythine (λmax=317.9 nm) having retention times (RT) 1.26, 2.12 and 3.64 min, respectively, in the extract obtained from Gelidium sp. Similarly, shinorine (λmax=332.3 nm), porphyra-334 (λmax=333.5 nm) and palythinol (λmax=332.5 nm) with RT 1.27, 2.13 and 4.61 min, respectively, were identified in the extract obtained from Ceramium sp. This study revealed that Gelidium sp. and Ceramium sp. could serve as potential source for economical exploration of MAAs in pharmaceutical sciences.Int. J. Appl. Sci. Biotechnol. Vol 5(1): 12-21

The Response of microRNAs to Solar UVR in Skin-Resident Melanocytes Differs between Melanoma Patients and Healthy Persons.

The conversion of melanocytes into cutaneous melanoma is largely dictated by the effects of solar ultraviolet radiation (UVR). Yet to be described, however, is exactly how these cells are affected by intense solar UVR while residing in their natural microenvironment, and whether their response differs in persons with a history of melanoma when compared to that of healthy individuals. By using laser capture microdissection (LCM) to isolate a pure population of melanocytes from a small area of skin that had been intermittingly exposed or un-exposed to physiological doses of solar UVR, we can now report for the first time that the majority of UV-responsive microRNAs (miRNAs) in the melanocytes of a group of women with a history of melanoma are down-regulated when compared to those in the melanocytes of healthy controls. Among the miRNAs that were commonly and significantly down-regulated in each of these women were miR-193b (P<0.003), miR-342-3p (P<0.003), miR186 (P<0.007), miR-130a (P<0.007), and miR-146a (P<0.007). To identify genes potentially released from inhibition by these repressed UV-miRNAs, we analyzed databases (e.g., DIANA-TarBase) containing experimentally validated microRNA-gene interactions. In the end, this enabled us to construct UV-miRNA-gene regulatory networks consisting of individual genes with a probable gain-of-function being intersected not by one, but by several down-regulated UV-miRNAs. Most striking, however, was that these networks typified well-known regulatory modules involved in controlling the epithelial-to-mesenchymal transition and processes associated with the regulation of immune-evasion. We speculate that these pathways become activated by UVR resulting in miRNA down regulation only in melanocytes susceptible to melanoma, and that these changes could be partially responsible for empowering these cells toward tumor progression.

Antagonistic and synergistic responses to solar ultraviolet radiation and increased temperature of phytoplankton from cenotes (sink holes) of the Yucatán Peninsula, México

Cenotes (sink holes) are karstic formations characteristic of the Yucatán Peninsula and are the main source of fresh water in the region. Because of their tropical location, they receive high levels of solar radiation and are exposed to high temperatures. However, the effect of these global-change-related variables on phytoplankton in cenotes is unknown. We carried out experiments with phytoplankton communities collected from 2 cenotes differing in their penetration of solar radiation (Leona Vicario [LV]: turbid, Las Mojarras [LM]: clear) to assess the combined effect of solar ultraviolet radiation (UVR; 280–400 nm) and increased temperature on their photosystem (PS) II photochemistry. We exposed samples in microcosms to solar radiation (with and without UVR) and 2 temperatures (ambient = 25°C and increased by 3°C) and analyzed photochemical performance over daily cycles. A significant antagonistic interaction between UVR and temperature in LV caused a combined inhibition of the effective photochemical quantum yield (ΦPSII) that was smaller (63%) than the sum of the 2 individual effects of UVR and temperature (116%). In contrast, a significant synergistic interaction between UVR and temperature in LM caused the combined inhibition of ΦPSII (172%) to be higher than the sum of the individual effects of the 2 variables (134%). Differences in the size distribution and taxonomic composition of the phytoplankton communities, with smaller cells in LV than in LM, seem to account for much of the variability in responses to UVR and increased temperature between the 2 communities. Our results suggest that phytoplankton communities from clear cenotes will be more affected by the combined effects of solar UVR and increased temperature that those from turbid cenotes.

Self-reported sunscreen use and urinary benzophenone-3 concentrations in the United States: NHANES 2003–2006 and 2009–2012

BackgroundSunscreens protect against skin cancer and other harmful effects of solar ultraviolet radiation (UVR). Epidemiologic and public health surveys often rely on self-reported sunscreen use to estimate sun exposure and avoidance, but questions remain about the validity of self-reports. Benzophenone-3 (BP-3), a common sunscreen ingredient, can be detected in the urine. Prior studies suggest that BP-3 concentrations increase after application of sunscreen. ObjectivesThe goal of this study was to assess the validity of self-reported frequency of sunscreen use in relation to urinary BP-3 concentrations in a representative sample of the general US population, including in sub-groups defined by age, sex and race/ethnicity. MethodsTo assess the relationship between categorical self-reported sunscreen use and creatinine-corrected urinary BP-3 concentrations, we conducted a linear regression adjusted for age, sex, race/ethnicity, six-month time period, body mass index, education, and sun avoidance behaviors. We tested for effect modification by age, sex, ethnicity and time period of measurement using multiplicative interaction terms and a F test. ResultsBP-3 was positively associated with self-reported frequency of sunscreen use across all ages, sexes, race/ethnicities, and time periods. Crude and multivariate adjusted models were all statistically significant. R-square was relatively low for all models, ranging from 0.15 to 0.43. ConclusionsUrinary BP-3 is positively associated with self-reported frequency of sunscreen use in the general US population, even in groups with overall low sunscreen use. These results suggest that self-report is a valid, although weak, way of assessing relative frequencies of sunscreen usage in a population-based study.

Effects of solar UV radiation and temperature on morphology and photosynthetic performance of Chaetoceros curvisetus

This study investigated the effect of solar ultraviolet radiation (UVR) and temperature on a chain length and photosynthetic performance of diatom Chaetorceros curvisetus. The cells were cultured in large quartz tubes and exposed to PAR, PAR + UV-A (PA), or PAR + UV-A + UV-B (PAB) radiation at 20°C and 28°C for six days, respectively. After recovery for 1 h, the cells were exposed again to three different radiations for 1 h. Then, a change in the photochemical efficiency (FPSII) was examined and UVR-induced photoinhibition was calculated. The percentage of long chains (more than five single cells per chain) in C. curvisetus significantly increased from 8.2% (PAR) to 38.9% (PAB) at 20°C; while it was not notably affected at 28°C. Mycosporine-like amino acids (MAAs) concentration obviously increased by irradiance increment from PAR to PAB at 20°C. Chlorophyll (Chl) a concentration significantly declined with increasing irradiance at 20°C. Both MAAs and Chl a concentrations were not obviously changed by irradiance at 28°C. Before and after reexposure, FPSII was significantly reduced both at 20°C and 28°C. UVR-induced photoinhibition at 20°C (39%) was higher than that at 28°C (30.9%). Solar UV radiation, especially UV-B, could significantly influence the percentage of long chains of C. curvisetus, especially at low temperature. UVR-induced photoinhibition can be alleviated by higher temperatures.

Oculocutaneous albinism in sub-Saharan Africa: adverse sun-associated health effects and photoprotection.

Oculocutaneous albinism (OCA) is a genetically inherited autosomal recessive condition. Individuals with OCA lack melanin and therefore are susceptible to the harmful effects of solar ultraviolet radiation, including extreme sun sensitivity, photophobia and skin cancer. OCA is a grave public health issue in sub-Saharan Africa with a prevalence as high as 1 in 1000 in some tribes. This article considers the characteristics and prevalence of OCA in sub-Saharan African countries. Sun-induced adverse health effects in the skin and eyes of OCA individuals are reviewed. Sun exposure behavior and the use of photoprotection for the skin and eyes are discussed to highlight the major challenges experienced by these at-risk individuals and how these might be best resolved.

A Hands-on Activity to Raise Awareness about Healthy Sun Exposure

Excessive exposure to solar ultraviolet (UV) radiation causes sunburn and has been consistently associated with increased susceptibility to melanoma and skin ageing. Acknowledging the need to promote healthy sun exposure habits, numerous educational initiatives have been developed to raise public awareness towards this issue. However, studies reveal that misinformed behaviours persist, particularly amongst young people, emphasising the need to broaden the range of interventions specifically targeting this population segment. The goal of this study was to develop and assess a hands-on activity addressing the lethal effect of sunlight. Using a mixed-method approach based on a case-control pre-/post-test design, the effectiveness of this activity was evaluated following its implementation in four high schools in Portugal. Data collected through questionnaires, classroom observations, analysis of activity reports and interviews with 140 12th-grade science students aged 17.10 ± 0.67 years old attending biology classes reveal that the activity had a positive impact on student knowledge about the effects of solar UV radiation and the importance of safe sunlight exposure. The implications of these findings for health and biology education–namely, concerning the instructional design of practical activities in this scope–are discussed.

Projected changes in clear-sky erythemal and vitamin D effective UV doses for Europe over the period 2006 to 2100

The benefits and the harmful effects of solar ultraviolet radiation (UVR) exposure have been well discussed. Most studies show concern for the solar overexposure in the tropics and low latitude sites and its scarcity at higher latitudes. Both cases are of concern, the first for diseases such as skin cancer and the second for the lack of vitamin D production in the skin. In this study, we evaluate the influence of climate change scenarios on the total ozone content (TOC) and typical aerosol properties, such as the optical depth (AOD) and single scattering albedo (SSA), over Europe. From these parameters, we estimate the erythemal and the vitamin D effective UVR doses from 2006 to 2100. Our results indicate a small reduction of the UVR daily doses caused by the ozone layer recovery and partially compensated by an AOD diminution through this century. The attenuation will be larger at high latitudes, during the springtime and for more polluted scenarios during this century. However, this diminution should not be sufficient to provide a protection condition for erythema. On the other hand, at higher latitudes, it possibly contributes to a relevant increase in the exposure time necessary for the synthesis of vitamin D, mainly during autumn and spring seasons.