Ultraviolet Irradiance Research Articles

Irradiance modeling of tubular ultraviolet light bulbs

Clean indoor air is crucial for human lives in residential and workplace settings, including food safety and supply chains. Since the COVID-19 outbreak, disinfecting air has become vital for the public as the SARS-CoV-2 virus and other infectious diseases transmit via inhalable aerosols. Ultraviolet (UV) light is known to be effective in disinfecting air. However, it is still challenging to properly design practical UV applications with common light design software. Visible light analysis software, AGi32, assists architectural applications. AGi32 utilizes digitized luminaire IES files to model light intensity on user-designed geometry in common far-field uses. IES files are based on far-field photometry to model light intensity at different distances and angles from the source. The common application of IES files is to model visible light intensities; however, IES files generated for UV light are still rarely available. Due to the increasing need for surface and air disinfection, modeling UV light intensity using IES files may be beneficial for designing and evaluating systems containing UV light bulbs in near-field applications. There is limited information regarding the accuracy of UV modeling in AGi32 software using IES files. Therefore, the research objectives were to (1) create IES files of a UV-C germicidal lamp (254 nm) and a visible fluorescent lamp with almost identical metrics; (2) compare the IES files output with physical UV measurements inside and outside of an air duct; (3) develop correlations between light intensities of visible and UV light bulbs. Linear correlations were observed when comparing UV irradiance and visible illuminance for both measured and modeled data. The results indicated high variability between the measured and modeled light data, signifying the importance of further investigation of potential error sources and improving the accuracy of modeling.

Electron Diffusion Length Effect on Direction of Irradiance in Transparent FAPbBr3 Perovskite Solar Cells.

Transparent photovoltaics for building integration represent a promising approach for renewable energy deployment. These devices require transparent electrodes to manage transmittance and to ensure proper cell operation. In this study, transparent FAPbBr3-based perovskite solar cells optimized via a passivation treatment were demonstrated with average visible transmittance values above 60% and light utilization efficiencies up to 5.0%. Experiments under varying ultraviolet (UV) irradiance intensities from both front and rear directions revealed performance differences correlated with diffusion-limited transport and open-circuit voltage changes. Combining the UV-radiated experiments and drift-diffusion simulations, an asymmetry between the diffusion lengths of electrons and holes in the perovskite is revealed, with estimated values resulting in less than 50 nm and more than 99 nm, respectively. Our methods not only identify electron-hole diffusion length differences but also introduce a general protocol for characterizing solar cells with transparent electrodes.

Solar Atmospheric Oscillations as Measured by the GOES-R Series EXIS EUVS-C Instrument

This Letter presents first observations of distinct solar atmospheric oscillations from signals collected by the Extreme Ultraviolet and X-ray Irradiance Sensors EUVS-C instrument, which is part of each Geostationary Observational Environmental Satellite R-Series instrument payload. The EUVS-C instrument is a full-disk, normal-incidence spectrograph that covers a narrow band in the mid-ultraviolet between 276 and 284 nm, where it can measure the magnesium ii emission doublet at ∼280 nm and the photospheric continuum. The primary goal of EUVS-C data is to construct the well-known Mg ii index, which is often used as a proxy for chromospheric activity. Because of the high temporal and spectral resolution of EUVS-C measurements, the data provide a unique opportunity to observe discernible solar atmospheric waves that have definite signatures of 3 and 5 minute oscillation periods, where the frequency response of these signals is dependent on what part of the spectrum is analyzed (e.g., Mg emission lines). Furthermore, both photospheric and chromospheric waves can simultaneously be examined. With the recent increase in solar activity for Solar Cycle 25, these waves exhibit enhanced amplitudes and phase shifts during the impulsive shock of strong solar flares. This Letter will discuss the analysis for deriving these waves, and results from both a quiescent Sun and an X-class solar flare event will be presented.

A composite photoluminescent probe based on Er/Yb co-doped tellurite glass powder for dual-parameter measurement of temperature and UV radiation

To cope with the cross-sensitivity of simultaneous measurement of ultraviolet (UV) irradiance and temperature, we propose and experimentally demonstrate a miniature composite photoluminescent probe that is formed by thoroughly mixing Er/Yb co-doped tellurite glass powder into a resin adhesive substrate. Utilizing tellurite glass in form of powder not only guarantees its thorough mixing into the liquid resin base, but also retains its amorphous glass phase for hosting Er/Yb ions, thus breaking the limitations of studying tellurite glass only in bulk or fibrous form. Co-excited by UV radiation and NIR pumping, the composite probe produces a superimposed fluorescence emission spectrum, where the intensity change rate of the 488 nm dip can be used for UV irradiance measurement, and the fluorescence intensity ratio (FIR) of the 524 nm and 545 nm peaks for temperature measurement. Based on the sensitive specificity of the resin substrate and the Er/Yb co-doped tellurite glass, we have realized the simultaneous measurement of UV and temperature without cross-sensitivity.

The Influence of Different Phases of a Solar Flare on Changes in the Total Electron Content in the Earth’s Ionosphere

Abstract Variations in X-ray and extreme ultraviolet (EUV) irradiance during solar flares lead to a noticeable increase in the electron concentration in the illuminated part of the Earth’s ionosphere. Due to the large amount of experimental data accumulated by global navigation satellite systems, the total electron content (TEC) response to the impulsive phase of a solar flare has been studied quite well. However, recent studies have shown that a large fraction of X-class flares have a second strong peak of warm coronal emission (which is called “EUV late phase”), whose influence on the ionization of ionospheric layers is not yet clear. A combined analysis of successive solar emissions and the caused TEC changes made it possible to numerically estimate the ionospheric response to the impulsive, gradual, and late phases of the X2.9 solar flare that occurred on 2011 November 3 and demonstrate the high geoeffectiveness of the rather weak Fe xv 28.4 nm solar emission during the EUV late phase. It was found that the ionospheric response to the relatively weak emissions of the EUV late phase of the X2.9 solar flare amounted to almost a third of the TEC increase during the impulsive phase.

Investigations on the surface disinfection efficacy of far-UVC 222nm germicidal irradiance device in a controlled environment and field test.

The Covid 19 pandemic has significantly affected the health, economy, and social impact of humanity. The continuous mutations of the virus variants have accelerated the demand for scientific research on disinfection techniques for a safer indoor environment. Among all the available surface disinfection techniques, ultraviolet germicidal irradiance at 254nm wavelength has been proven for its disinfection efficacy; however, its usage is limited to unoccupied conditions due to the risk of ultraviolet exposure. This study investigated the efficacy of far-UVC-222nm experimentally in both controlled environment and field setting. Staphylococcus epidermidis and Mycobacterium smegmatis were employed for surface disinfection in both the laboratory and a meeting room. Total plate count was used to determine the disinfection efficacy by a 20W unfiltered far-UVC lamp. At 1.1 µW/cm2 far-UVC irradiation, a 1-log10 reduction of Staphylococcus epidermidis and Mycobacterium smegmatis contamination on tabletop can be achieved by 31.3min and 101.8min of far-UVC irradiation, respectively. Other pathogens of interest such as Staphylococcus aureus, Mycobacterium tuberculosis, Legionella pneumophila, SARS-CoV-2, and the Measles virus were also referred and compared in this study. This study carefully examined how far-UVC irradiation performs effectively for surface disinfection in a real meeting room setting. The results offer useful recommendations for alternatives to upper-room ultraviolet germicidal irradiance for continuous disinfection within the ultraviolet threshold limit value, with the goal of preventing the spread of any diseases in the future.

Damage regularity and multifractal analysis of sol-gel reflection coating of KDP crystal under low UV irradiation flux.

This study employed multifractal analysis to investigate the changes in surface morphology of SiO2 anti-reflective coatings prepared on KDP substrates using the sol-gel method, under various conditions of ultraviolet (UV) irradiance. The coatings were successfully fabricated, and the chemical structure of the SiO2 sol was comprehensively characterized using Solid-State Nuclear Magnetic Resonance (SSNMR) technology. Under low UV irradiance (4 J/cm2), repeated experiments revealed a crack-induced mechanism of surface fatigue damage. Utilizing Scanning Electron Microscopy (SEM), the study discovered the induction effect of initial crack defects in UV-damaged coatings and established a damage model. Furthermore, Atomic Force Microscopy (AFM) was used to acquire images of the coatings' surface morphology at different damage levels, which were analyzed using the multifractal spectrum f(α). This analysis confirmed the multifractal nature of the coatings both before and after damage. This study identified significant effects of UV irradiation on the width of the multifractal spectrum and Δf, indicating that the SiO2 anti-reflective coatings exhibit multifractal characteristics under various damage states. The coatings displayed a pattern of decreasing and then increasing singularity spectrum width, height distribution unevenness, and surface roughness with increasing damage. This study demonstrates that multifractal analysis is an effective tool for describing the complexity of the surface morphology of sol-gel-derived anti-reflective coatings for the first time and for validating their multifractal properties across different stages of UV damage. HIGHLIGHTS: Damage dynamic process of KDP crystal sol-gel coating was described by SEM&AFM; The crack propagation mechanism of sol-gel coating under UV radiation is proposed; The damage evolution of sol-gel coating was described by multifractal analysis.

A quality-assured dataset of nine radiation components observed at the Shangdianzi regional GAW station in China (2013–2022)

Abstract. The New Baseline Surface Radiation (NBSR) system was established at the Shangdianzi (SDZ) regional Global Atmosphere Watch (GAW) station in 2013 to observe nine broadband radiation components, i.e. the global, direct, diffuse, and upwelling shortwave irradiance (GSWI, DSWI, DifSWI, and UpSWI); the photosynthetically active radiation (PAR); the ultraviolet irradiance (UVAI and UVBI); and the down- and upwelling longwave irradiance (DnLWI and UpLWI). To test the 1 min raw radiometric data, a Hybrid Algorithm for Radiation Data Quality Control (HARDQC) is presented in this study based on well-established methods, together with the solar irradiance dataset and the spectral features of the instrument bands. Subsequently, a NBSR dataset, which consists of radiation data at multiple timescales (i.e. 1 min, hourly, daily, monthly, monthly average hourly, and monthly average daily) over 2013–2022, is established and evaluated. Results show that more than 98.7 % of all radiation components passed the physical possibility test. The percentages of those that passed the extremely rare test are greater than 98.6 % for all radiation components except for the DnLWI (97.1 %). The percentages of those that passed the comparison test are greater than 83.3 % (GSWI), 78.3 % (DSWI), 81.7 % (DifSWI), 93.1 % (UpSWI), 88.9 % (PAR), 95.6 % (UVAI), 96.3 % (UVBI), 99.8 % (DnLWI), and 99.7 % (UpLWI), respectively. Due to data logger faults, removal of the instruments for calibration, and lightning strikes, some apparent data gaps in the upwelling radiation components (January 2015–August 2017) and all radiation components (December 2018; July to September 2021) were detected. Despite the existence of a few imperfections in the NBSR dataset, it is still reliable to apply it in many fields such as the validation of satellite products and numerical models, the investigation of relationships between radiation and atmospheric composition, and the detection of changes in the surface fluxes. The dataset described in this paper is available at https://doi.org/10.1594/PANGAEA.963330 (Quan et al., 2023b).

Design optimization of Solar Power Inverter using the GRA Method

Among the most crucial components of a solar-powered system is an inverter. It is an apparatus that transforms the direct current (DC) produced by solar panels into the alternating current (AC) required by the electric system. Flashing hybrid solar inverter is the best solar inverter for home which offers the following features: - Its operating voltage is between 100-290V. - It has 700 VA of power. 5kW solar inverter price budget starts at $2,000 for excellent single-phase devices and $1,000 for existing datasets (like Sungrow) (eg Fronius or SMA). The most popular size, 5kW, can accommodate arrays up to 6.6kW in power. A solar charge controller can only function effectively during the day, because when the ultraviolet irradiance is strong and, the system's Voltage rating must reach the inverter at a moderate DC voltage level in order for it to function. Your photovoltaic systems and inverter operate at night power will be off. The inverter doesn't run overnight because it doesn't want to draw electricity. Instead, it rises again in the morning when the sun shines. Your home and solar system are connected to the utility grid. By switching to solar PV-based power generation from the airport's current conventional energy source, the carbon footprint of the facility can be decreased. Power distribution solar PV power facilities may be built in regions that are required to be broad and free of obstructions around runways. Based on first year operating data, the current study seeks to evaluate the operational efficiency of a 12 MWp solar-powered airport at Cochin Airport Limited (CIAL), India. With the aid of the most well-liked PV simulation programmes, such as Deterioration in quality and Solar Gis, the plant effectiveness is precisely rendered. The software's performance metrics were discovered to perfectly resemble the observed values. Economic and ecological studies of Kochi airports powered by solar energy attest to its efficiency in lowering carbon footprint, resulting in an airport with almost no emissions that is clean, green, and sustainable.Gray correlation analysis is widely used to measure the degree of relationship between sequences through the gray correlation coefficient. Gray relational analysis has been used by many researchers to optimize control parameters with multiple responses through gray relational grading. The fundamental tenet of the GRA approach is that the chosen option must have the "greatest degree of Green relation" to the positive-ideal solution and the "minimum of grey relation" to the negative-best answer. A technique for determining whether or not variables are connected and how much they are correlated is called grey correlation coefficient analysis. The primary method of determining these curves' geometric similarity is by the construction of characteristic series curves. Type of Solar Module, No of modules per string, No of string, No of inverters and No of transformers Short circuit current (ISC), Open circuit voltage (VOC), Operating Temperature and Dimension. Stress Management in Healthcare Institutions in Work overload is got the first rank whereas is the Overtime is having the lowest rank.

A Comparative Analysis of the Solar Ultraviolet Spectral Irradiance Measured from Earth and Mars: Toward a General Empirical Model for the Study of Planetary Aeronomy

Accurate estimation of the solar vacuum ultraviolet irradiance between 0.1 and 200 nm is critical for the study of planetary aeronomy. Previous empirical models have relied on a limited number of reference spectra, or on multiple data sets with various degrees of uncertainty, and on an empirical selection of solar proxies. Here we propose a novel method for the development of empirical models based on Fourier transform and least-squares fitting of the long-term measurements from the Solar EUV Experiment on the Thermosphere Ionosphere Mesosphere Energetics and Dynamics mission. A Fourier transform analysis is performed to examine a large number of solar proxies, which reveals that the solar radio flux at 10.7 cm and the solar Lyα flux at 121.6 nm are better proxies for solar irradiance below and above ∼120 nm, respectively. Using these two proxies, a nonlinear empirical model is developed through Fourier transform and least-squares fitting of solar irradiance measurements, which can reproduce the solar irradiance with uncertainties of only ∼1%–2% above ∼120 nm, ∼2%–4% within ∼45–120 nm, and ∼4%–8% below ∼45 nm. Comparison with measurements from the Extreme Ultraviolet Monitor on the Mars Atmosphere and Volatile Evolution mission indicates that the solar irradiance at Mars can be predicted with uncertainties of less than ∼8% by geometric extrapolation of the solar irradiance measured from Earth, provided that the measurements from Earth can be calibrated accurately. Our study provides a general method for the development of empirical models using long-term observations in planetary aeronomy.

Characterisation and photo-fatigue behaviour of UV-sensitive photochromic systems produced using electrospinning

This research aimed to create a UV sensor using photochromic pigment in nonwoven form and analyse its fatigue resistance under continuous ultraviolet (UV) light. The photochromic polymeric matrices consist of a photochromic pigment, a polymer, and a photo stabilizer, which enhance the stability of the photochromic systems under light exposure. As a base matrix, we used polyvinyl butyral. Then, we added different amounts of the photochromic pigment 5-chloro-1,3,3-trimethylspiro [indoline-2,3′-(3H) naphtho (2,1-b) (1,4)-oxazine]. We produce photochromic nonwovens by electrospinning a polymeric matrix solution with varying pigment concentrations. The study aimed to create a UV sensor with photochromic nanofibers that are very sensitive to light. It also tested how well it can degrade under continuous UV radiation by looking at its photo fatigue resistance under constant UV irradiation for its final use as a UV sensor material. Using FTIR, CRM, SEM, and XRD techniques, this study investigates the physiochemical properties and photodegradation behaviour of photochromic nonwovens and writes a report on it. The photo-light stability of photochromic materials is a major problem concerning its external stimuli in different substrate forms. It also looks at how well they resist photo-chemically towards the UV light. The fatigue resistance measurements were carried out using a FOTOCHROM3 spectrophotometer under continuous UV irradiance using two different modes. This study evaluated and reported their photodegradation behaviour in cyclic and continuous UV irradiance modes. The tests showed that the prepared photochromic system works well with photostability and can go through more than 20 exposure cycles, each with 100 min of UV light and intensity equal to 1/3 of the sun’s rays on a clear day. Given the PVB applications in our daily lives, it can serve as a UV sensor in numerous industrial applications. Photochromic nanofibers possessing excellent photosensitivity hold immense promise as optical rewritable devices and colourimetric-based UV sensors.

Monte Carlo Evaluation of Uncertainties of UV Spectra Measured With Brewer Spectroradiometers

AbstractPrecise spectral ultraviolet (UV) measurements are needed to ensure human protection as well as to support scientific research. Quantifying the uncertainty of the UV spectra recorded is crucial to evaluate the quality of the measurements which is needed, in turn, for the assessment of their reliability. However, for double‐monochromator spectroradiometers, the analytical derivation of this uncertainty is a challenging task due to the difficulties involved in propagating individual uncertainties. Under these circumstances, a Monte Carlo simulation is a reliable alternative as it does not require the calculation of partial derivatives and considers both nonlinear effects and correlations in the data. In the present study, the uncertainty of the spectral UV irradiance measured by a Brewer MKIII spectrophotometer is evaluated using a Monte Carlo approach. This instrument belongs to the National Institute of Aerospace Technology and has successfully participated in several international campaigns, which ensures its precise calibration. The average expanded uncertainty (k = 2) of the global UV irradiance measured by this instrument varies between 10% at 300 nm and 7% at 363 nm. At shorter wavelengths, it increases sharply due to thermal and electronic noise as well as wavelength misalignment. The results indicate that a Brewer spectrophotometer is suitable for climatological studies and model validation. Nevertheless, a substantial reduction of these uncertainties might be required for accurately detecting long‐term UV trends. Although the study focused on a Brewer spectrometer, the methodology used for the uncertainty analysis is general and can be adapted to most UV spectroradiometers.

Ultraviolet Erythemal Irradiance (UVER) under Different Sky Conditions in Burgos, Spain: Multilinear Regression and Artificial Neural Network Models

Different strategies for modeling Global Horizontal UltraViolet Erythemal irradiance (GHUVE) based on meteorological parameters measured in Burgos (Spain) have been developed. The experimental campaign ran from September 2020 to June 2022. The selection of relevant variables for modeling was based on Pearson’s correlation coefficient. Multilinear Regression Model (MLR) and artificial neural network (ANN) techniques were employed to model GHUVE under different sky conditions (all skies, overcast, intermediate, and clear skies), classified according to the CIE standard on a 10 min basis. ANN models of GHUVE outperform those based on MLR according to the traditional statistical indices used in this study (R2, MBE, and nRMSE). Moreover, the work proposes a simple all-sky ANN model of GHUVE based on usually recorded variables at ground meteorological stations.

Effect of the ultraviolet unweighted irradiance on the compliance of sunbeds in Spain.

The use of tanning devices in Spain is regulated by the Royal Decree 1002/2002, which is based on the European standard EN60335-2-27. The European standard establishes that the total unweighted irradiance between 200 and 280 nm must not exceed 0.003 Wm-2, a requirement that the Spanish regulation modified to 0.03 Wm-2 from 250 to 295 nm. With these differences, the compliance consideration of an artificial tanning device can vary. Spectral irradiance measurements of 41 tanning devices performed with a high-resolution spectroradiometer were analyzed. None of the tanning devices had irradiances higher than 0.003 Wm-2 between 250 (the shortest wavelength measured by the spectroradiometer) and 280 nm, but the limit required by Spanish regulation was exceeded by 11 devices, of which one would have been considered compliant according to the European standard since the effective irradiance was lower than 0.3 Wm-2. Beyond noting the differences that can occur in sunbed inspections according to the established criteria, this work has shown the differences in the spectral and total values of devices in use in Spain, validating the need for periodic inspections.

The Next Decade of Solar Ultraviolet Spectral Irradiance — Continuity, Modeling, and Physics

The Next Decade of Solar Ultraviolet Spectral Irradiance — Continuity, Modeling, and Physics

Effectual visible light photocatalytic reduction of para-nitro phenol using reduced graphene oxide and ZnO composite

Removing wastewater pollutants using semiconducting-based heterogeneous photocatalysis is an advantageous technique because it provides strong redox power charge carriers under sunlight irradiation. In this study, we synthesized a composite of reduced graphene oxide (rGO) and zinc oxide nanorods (ZnO) called rGO@ZnO. We established the formation of type II heterojunction composites by employing various physicochemical characterization techniques. To evaluate the photocatalytic performance of the synthesized rGO@ZnO composite, we tested it for reducing a common wastewater pollutant, para-nitro phenol (PNP), to para-amino phenol (PAP) under both ultraviolet (UV) and visible light irradiances. The rGOx@ZnO (x = 0.5–7 wt%) samples, comprising various weights of rGO, were investigated as potential photocatalysts for the reduction of PNP to PAP under visible light irradiation. Among the samples, rGO5@ZnO exhibited remarkable photocatalytic activity, achieving a PNP reduction efficiency of approximately 98% within a short duration of four minutes. These results demonstrate an effective strategy and provide fundamental insights into removing high-value-added organic water pollutants.

Using Direct Solar Energy Conversion in Distillation via Evacuated Solar Tube with and without Nanomaterials

As is widely known, the issue of freshwater scarcity affects practically all people, and all are looking for innovative and workable ways to attempt to solve this issue. In this work, a novel method of desalination is proposed. The proposed system consists of a solar collector (PTSC), evacuated pipe (EP), condenser (CU), and separation unit (SU). The working principle of the system is heating the feed saline water using the PTSC and EP and controlling the water flow rate to control the output conditions of the EP. The produced vapor is therefore separated from salty water using the SU. In addition, the generated steam is condensed into the CU to produce a freshwater distillate. Consequently, the effect of solar radiation on the affecting temperatures was tested. In addition, the effect of using different water flow rates (6, 7.5, 10, 20, 40, and 60 L/h) inside the EP on the system productivity was investigated. The primary findings of this work may be highlighted in relation to the experiments conducted. At midday, when ultraviolet irradiance reached its highest, the EP’s water flow entrance and outflow had the largest temperature differential. In addition, the lower the water flow rate inside the EP, the higher the water temperature, the higher the evaporation rate of the system, and the greater the freshwater productivity of the system. At 6 L/h, the water’s highest temperature was 92 °C. Moreover, the best performance of the system was obtained at 7.5 L/h, where the freshwater production and average daily effectiveness of the distillate process were 44.7 L/daytime and 59.6%, respectively. As well, the productivity of EP was augmented by around 11.86% when using graphite nanoparticles. Additionally, the distilled freshwater from the system operating at the flow rate of 7.5 L/h costs 0.0085 $/L.

Stratospheric ozone, UV radiation, and climate interactions

This assessment provides a comprehensive update of the effects of changes in stratospheric ozone and other factors (aerosols, surface reflectivity, solar activity, and climate) on the intensity of ultraviolet (UV) radiation at the Earth’s surface. The assessment is performed in the context of the Montreal Protocol on Substances that Deplete the Ozone Layer and its Amendments and Adjustments. Changes in UV radiation at low- and mid-latitudes (0–60°) during the last 25 years have generally been small (e.g., typically less than 4% per decade, increasing at some sites and decreasing at others) and were mostly driven by changes in cloud cover and atmospheric aerosol content, caused partly by climate change and partly by measures to control tropospheric pollution. Without the Montreal Protocol, erythemal (sunburning) UV irradiance at northern and southern latitudes of less than 50° would have increased by 10–20% between 1996 and 2020. For southern latitudes exceeding 50°, the UV Index (UVI) would have surged by between 25% (year-round at the southern tip of South America) and more than 100% (South Pole in spring). Variability of erythemal irradiance in Antarctica was very large during the last four years. In spring 2019, erythemal UV radiation was at the minimum of the historical (1991–2018) range at the South Pole, while near record-high values were observed in spring 2020, which were up to 80% above the historical mean. In the Arctic, some of the highest erythemal irradiances on record were measured in March and April 2020. For example in March 2020, the monthly average UVI over a site in the Canadian Arctic was up to 70% higher than the historical (2005–2019) average, often exceeding this mean by three standard deviations. Under the presumption that all countries will adhere to the Montreal Protocol in the future and that atmospheric aerosol concentrations remain constant, erythemal irradiance at mid-latitudes (30–60°) is projected to decrease between 2015 and 2090 by 2–5% in the north and by 4–6% in the south due to recovering ozone. Changes projected for the tropics are ≤ 3%. However, in industrial regions that are currently affected by air pollution, UV radiation will increase as measures to reduce air pollutants will gradually restore UV radiation intensities to those of a cleaner atmosphere. Since most substances controlled by the Montreal Protocol are also greenhouse gases, the phase-out of these substances may have avoided warming by 0.5–1.0 °C over mid-latitude regions of the continents, and by more than 1.0 °C in the Arctic; however, the uncertainty of these calculations is large. We also assess the effects of changes in stratospheric ozone on climate, focusing on the poleward shift of climate zones, and discuss the role of the small Antarctic ozone hole in 2019 on the devastating “Black Summer” fires in Australia. Additional topics include the assessment of advances in measuring and modeling of UV radiation; methods for determining personal UV exposure; the effect of solar radiation management (stratospheric aerosol injections) on UV radiation relevant for plants; and possible revisions to the vitamin D action spectrum, which describes the wavelength dependence of the synthesis of previtamin D3 in human skin upon exposure to UV radiation.Graphical abstract

Insight into micropollutant abatement during ultraviolet light-emitting diode combined electrochemical process: Reaction mechanism, contributions of reactive species and degradation routes

Electrochemical process coupling with ultraviolet light-emitting diode for micropollutant abatement was evaluated in the treatment of wastewater containing Cl−. Four representative micropollutants, atrazine, primidone, ibuprofen and carbamazepine, were selected as target compounds. The impacts of operating conditions and water matrix on micropollutant degradation were investigated. Fluorescence excitation-emission matrix spectroscopy spectra and high performance size exclusion chromatography were employed to characterize the transformation of effluent organic matter in treatment. The degradation efficiencies of atrazine, primidone, ibuprofen and carbamazepine are 83.6 %, 80.6 %, 68.7 % and 99.8 % after 15 min treatment, respectively. The increment of current, Cl− concentration and ultraviolet irradiance promote the micropollutant degradation. However, the presence of bicarbonate and humic acid inhibit micropollutant degradation. The mechanism of micropollutant abatement was elaborated based on reactive species contributions, density functional theory calculation and degradation routes. Free radicals (HO•, Cl•, ClO• and Cl2•-) could be generated by chlorine photolysis and subsequent propagation reactions. The concentrations of HO• and Cl• are 1.14 × 10−13 M and 2.0 × 10−14 M in optimal condition, respectively, and the total contributions of HO• and Cl• for the degradation of atrazine, primidone, ibuprofen and carbamazepine are 24 %, 48 %, 70 % and 43 %, respectively. The degradation routes of four micropollutants are elucidated based on intermediate identification, Fukui function and frontier orbital theory. Micropollutants can be effectively degraded in actual wastewater effluent, and the small molecule compound proportion increases during effluent organic matter evolution. Compared with photolysis and electrolysis, the coupling of the two processes has potential for energy saving in micropollutant degradation, which shed light on the prospects of ultraviolet light-emitting diode coupling with electrochemical process for effluent treatment.

Ultraviolet light exposure and its penetrance through the eye in a porcine model.

To determine the amount of ultraviolet (UV) light irradiance that various layers of the eye receive as sunlight passes through the eye, and to investigate the protective benefits of UV light-blocking contact lenses. Twenty-four porcine eyes were prepared in one of three ways: isolated cornea, cornea and lens together, or whole eye preparation. UV light irradiance was measured with a UV-A/B light meter before and after the eye preparations were placed over the meter to measure UV light penetration in each eye structure. In the whole eye preparation, a hole was placed in the fovea to measure light as it passed through the vitreous. Subsequently, UV-protective contact lenses were placed over the structures, and UV light penetrance was measured. Measurements of UV light exposure were taken outdoors at various locations and times. Cornea absorbed 63.56% of UV light that reached the eye. Cornea and lens absorbed 99.34% of UV light. Whole eye absorbed 99.77% of UV light. When UV-protective contact lenses were placed, absorption was 98.90%, 99.55%, and 99.87%, respectively. UV light exposure was dependent on directionality and time of day, and was greatest in areas of high albedo that reflect significant amounts of light, such as a beach. Cornea absorbs the majority of UV light that reaches the eye in this model. UV-protective contact lenses reduce UV exposure to the eye. Locations with high albedo expose the eye to higher levels of UV light.