scholarly journals Solar UV-B/A radiation is highly effective in inactivating SARS-CoV-2

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Fabrizio Nicastro ◽  
Giorgia Sironi ◽  
Elio Antonello ◽  
Andrea Bianco ◽  
Mara Biasin ◽  
...  
Keyword(s):  
Solar Radiation ◽  
Open Space ◽  
Uv Light ◽  
Rna Virus ◽  
Action Spectrum ◽  
Solar Irradiation ◽  
Mortality Data ◽  
Solar Uv ◽  
Solar Pump ◽  
Set Up

AbstractSolar UV-C photons do not reach Earth’s surface, but are known to be endowed with germicidal properties that are also effective on viruses. The effect of softer UV-B and UV-A photons, which copiously reach the Earth’s surface, on viruses are instead little studied, particularly on single-stranded RNA viruses. Here we combine our measurements of the action spectrum of Covid-19 in response to UV light, Solar irradiation measurements on Earth during the SARS-CoV-2 pandemics, worldwide recorded Covid-19 mortality data and our “Solar-Pump” diffusive model of epidemics to show that (a) UV-B/A photons have a powerful virucidal effect on the single-stranded RNA virus Covid-19 and that (b) the Solar radiation that reaches temperate regions of the Earth at noon during summers, is sufficient to inactivate 63% of virions in open-space concentrations (1.5 × 103 TCID50/mL, higher than typical aerosol) in less than 2 min. We conclude that the characteristic seasonality imprint displayed world-wide by the SARS-Cov-2 mortality time-series throughout the diffusion of the outbreak (with temperate regions showing clear seasonal trends and equatorial regions suffering, on average, a systematically lower mortality), might have been efficiently set by the different intensity of UV-B/A Solar radiation hitting different Earth’s locations at different times of the year. Our results suggest that Solar UV-B/A play an important role in planning strategies of confinement of the epidemics, which should be worked out and set up during spring/summer months and fully implemented during low-solar-irradiation periods.

scholarly journals Hourly resolved cloud modification factors in the ultraviolet

2008 ◽  
Vol 8 (1) ◽  
pp. 181-214 ◽  
Author(s):  
H. Staiger ◽  
P. N. den Outer ◽  
A. F. Bais ◽  
U. Feister ◽  
B. Johnsen ◽  
...  
Keyword(s):  
Solar Radiation ◽  
Uv Radiation ◽  
Rayleigh Scattering ◽  
Weather Prediction ◽  
Global Radiation ◽  
Action Spectrum ◽  
Solar Irradiation ◽  
Solar Disc ◽  
Global Irradiance ◽  
The Cost

Abstract. Cloud impacts on the transfer of Ultraviolet (UV) radiation through the atmosphere can be assessed using a cloud modification factor (CMF). The total global solar irradiation has proven to be a solid basis to derive CMF's for the UV radiation (UV_CMF). Total global irradiance is frequently measured and forecasted by numerical weather prediction systems. Its advantage compared to for instance cloud cover is that measured solar global irradiance contains already the effect of multiple reflection between cloud layers, reflection between the sides of the clouds, as well as the distinct difference whether the solar disc is obscured by clouds or not. In the UV range clouds decrease the irradiance to a lesser extent than in the visible and infrared spectral range; Rayleigh scattering in the atmosphere yields a larger fraction of scatter radiation compared to that of light and infrared, hence, obscuring the solar disc will not totally block out the irradiation. Thus the relationship between CMF's for solar radiation and for UV-radiation is not straight forwards, but will depend on e.g. the solar zenith angle (SZA) and wavelength band or action spectrum in the UV considered. Den Outer et al. (2005) provide a UV_CMF algorithm on a daily base accounting for these influences. It requires as input a daily CMF in total global radiation (SOL_CMF) and the SZA at noon. The calculation of SOL-CMF uses the clear sky algorithm of the European Solar Radiation Atlas to account for varying turbidity impacts. The algorithm's capability to derive hourly UV_CMF's based on the SZA at the corresponding hour and its worldwide applicability is validated using hourly resolved observational data retrieved from the databases of the COST-Action 726 on "Long term changes and climatology of UV radiation over Europe" and the USDA UV-B Monitoring and Research Program. The model performance for hourly resolution is shown to be comparable in absolute and relative deviations from a measured mean smoothed dependent on SZA with the well performing daily models of the COST-726 model intercomparison (Koepke et al., 2006).

scholarly journals UV-A and UV-B Can Neutralize SARS-CoV-2 Infectivity

2021 ◽  
Author(s):  
Mara Biasin ◽  
Sergio Strizzi ◽  
Andrea Bianco ◽  
Alberto Macchi ◽  
Olga Utyro ◽  
...  
Keyword(s):  
Uv Light ◽  
Action Spectrum ◽  
Summer Season ◽  
Solar Irradiation ◽  
Viral Inactivation ◽  
Violet Light ◽  
Depth Analysis ◽  
Virucidal Effect ◽  
Uv C

We performed an in-depth analysis of the virucidal effect of discrete wavelengths: UV-C (278 nm), UV-B (308 nm), UV-A (366 nm) and violet (405 nm) on SARS-CoV-2. By using a highly infectious titer of SARS-CoV-2 we observed that the violet light-dose resulting in a 2-log viral inactivation is only 10-4 times less efficient than UV-C light. Moreover, by qPCR and fluorescence in situ hybridization (FISH) approach we verified that the viral titer typically found in the sputum of COVID-19 patients can be completely inactivated by the long UV-wavelengths corresponding to UV- A and UV-B solar irradiation. The comparison of the UV action spectrum on SARS-CoV-2 to previous results obtained on other pathogens suggests that RNA viruses might be particularly sensitive to long UV wavelengths. Our data extend previous results showing that SARS-CoV-2 is highly susceptible to UV light and offer an explanation to the reduced incidence of SARS-CoV-2 infection seen in the summer season.

scholarly journals Degradasi Zat Warna Direct Red-23 Secara Fotolisis dengan Katalis C-N-codoped TiO2

2017 ◽  
pp. 151-159
Author(s):  
Yuli Okta Fitriyani ◽  
Upita Septiani ◽  
Diana Vanda Wellia ◽  
Reza Audina Putri ◽  
Safni Safni
Keyword(s):  
Solar Radiation ◽  
Textile Industry ◽  
Uv Light ◽  
Solar Irradiation ◽  
Azo Compounds ◽  
Industrial Processes ◽  
Tio2 Catalyst ◽  
Codoped Tio2 ◽  
Optimum Weight

Zat warna direct red-23 merupakan pewarna sintetik dengan struktur senyawa organik yang bersifat non-biodegradable. Zat warna direct red-23 mengandung senyawa azo dan bersifat karsinogenik. Zat warna direct red-23 didegradasi secara fotolisis menggunakan sinar UV (ultraviolet), sinar matahari, tanpa dan dengan penambahan katalis C-N-codoped TiO2. Larutan zat warna direct red-23setelah dan sebelum didegradasi diukur dengan spektrofotometer UV-Vis pada panjang gelombang 400-800 nm. Penentuan berat optimum katalis C-N-codoped TiO2 dilakukan dengan metode fotolisis sinar UV dan didapatkan berat optimum 15 mg. Persen degradasi zat warna direct red-23 secara fotolisis sinar UV dan sinar matahari tanpa katalis C-N-codoped TiO2 27.47% dan 13.74%. Persen degradasi meningkat menjadi 68.68% dan 28.57% dengan penambahan 15 mg katalis C-N-codoped selama 120 menit fotolisis. Dari penelitian dapat disimpulkan metode fotolisis dengan sinar UV lebih efisien dibandingkan dengan sinar matahari. Direct red-23 dye is a synthetic dye that is widely used in textile industry. Wastes generated from textile industrial processes are generally non-biodegradable organic compounds containing azo compounds and carcinogenic. Direct red-23 dye was degraded by photolysis UV Light method,  solar irradiation, without and addition of C-N-codoped TiO2 catalyst. The results degradation of direct red-23 were measured with a UV-Vis spectrophotometer at wavelength of 400-800 nm. Determination of optimum weight of the C-N-codoped TiO2 catalyst was performedby photolysisUV Light methodand the optimum C-N-codoped TiO2catalyst is obtained 15 mg. Percent degradation of direct red-23 dye by photolysis of UV light and solar irradiation without C-N-codoped TiO2to 27.47% and 13.74%. Percent degradation increasedto 68.68% and 28.57% by addingC-N-codoped TiO2 catalyst was adding 120 menutes of photolysis.From the research it can be concluded by photolysis with UV Light methodis more efficient compared to solar radiation.

scholarly journals Hourly resolved cloud modification factors in the ultraviolet

2008 ◽  
Vol 8 (9) ◽  
pp. 2493-2508 ◽  
Author(s):  
H. Staiger ◽  
P. N. den Outer ◽  
A. F. Bais ◽  
U. Feister ◽  
B. Johnsen ◽  
...  
Keyword(s):  
Solar Radiation ◽  
Uv Radiation ◽  
Weather Prediction ◽  
Action Spectrum ◽  
Monitoring Program ◽  
Daily Basis ◽  
Solar Irradiation ◽  
Cloud Optical Depth ◽  
Clear Sky ◽  
The Cost

Abstract. Cloud impacts on the transfer of ultraviolet (UV) radiation through the atmosphere can be assessed by using a cloud modification factor (CMF). CMF, which is based on total global solar irradiation (SOLCMF), has proved to be a solid basis to derive CMFs for the UV radiation (UVCMF). This is an advantage, because total global irradiance, the basis for SOLCMF, is frequently measured and forecasted by numerical weather prediction systems and includes all relevant effects for radiation transmission, such as cloud optical depth, different cloud layers, multiple reflection, as well as the distinct difference as to whether the solar disc is obscured by clouds or not. In the UV range clouds decrease the irradiance to a lesser extent than in the visible and infrared spectral range. Thus the relationship between CMFs for solar radiation and for UV-radiation is not straight forward, but will depend on whether, for example, the solar zenith angle (SZA) and wavelength band or action spectrum in the UV have been taken into consideration. Den Outer et al. provide a UVCMF algorithm on a daily basis, which accounts for these influences. It requires as input a daily SOLCMF and the SZA at noon. The calculation of SOLCMF uses the clear-sky algorithm of the European Solar Radiation Atlas to account for varying turbidity impacts. The algorithm's capability to derive hourly UVCMFs based on the SZA at the corresponding hour and its worldwide applicability is validated for erythemal UV using observational data retrieved from the databases of the COST-Action 726 on "Long-term changes and climatology of UV radiation over Europe" and the USDA UV-B Monitoring Program. The clear-sky part of the models has proved to be of good quality. Accumulated to daily doses it forms a tight cluster of points to the highest measured daily sums. All sky model performances for hourly resolution are shown to be comparable in accuracy with the well performing daily models of the COST-726 model intercomparison.

scholarly journals Effects of solar radiation on collagen-based biomaterials

2006 ◽  
Vol 2006 ◽  
pp. 1-6 ◽  
Author(s):  
Alina Sionkowska ◽  
Marcin Wisniewski ◽  
Joanna Skopinska ◽  
Diego Mantovani
Keyword(s):  
Thin Films ◽  
Solar Radiation ◽  
Uv Radiation ◽  
Synthetic Polymer ◽  
Vinyl Pyrrolidone ◽  
Solar Irradiation ◽  
Poly Vinyl Alcohol ◽  
Solar Uv ◽  
Poly Vinyl Pyrrolidone ◽  
Artificial Uv

The effect of solar radiation on collagen and collagen/synthetic polymer blends in the form of thin films and solutions has been studied by UV-VIS and FTIR spectroscopies. Films and solutions of collagen blended with poly(vinyl alcohol) (PVA) and poly(vinyl pyrrolidone) (PVP) were irradiated by solar light. It was found that UV-VIS spectra, which characterize collagen, collagen/PVA, and collagen/PVP blended films, were significantly altered by solar radiation. FTIR spectra of collagen, collagen/PVA, and collagen/PVP films showed that after solar irradiation, the positions of Amide A bands were shifted to lower wavenumbers. There was not any significant alteration in the position of Amide I and Amide II bands of collagen and its blends after solar radiation. The effect of solar UV radiation in comparison with artificial UV radiation has been discussed.

scholarly journals Calibration and Validation of ArcGIS Solar Radiation Tool for Photovoltaic Potential Determination in the Netherlands

Energies ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1865
Author(s):  
Bala Bhavya Kausika ◽  
Wilfried G. J. H. M. van Sark
Keyword(s):  
Solar Radiation ◽  
The Netherlands ◽  
Urban Areas ◽  
Input Data ◽  
Solar Irradiation ◽  
Energy Yield ◽  
Atmospheric Parameters ◽  
Factors Affecting ◽  
Calibration And Validation ◽  
Solar Radiation Model

Geographic information system (GIS) based tools have become popular for solar photovoltaic (PV) potential estimations, especially in urban areas. There are readily available tools for the mapping and estimation of solar irradiation that give results with the click of a button. Although these tools capture the complexities of the urban environment, they often miss the more important atmospheric parameters that determine the irradiation and potential estimations. Therefore, validation of these models is necessary for accurate potential energy yield and capacity estimations. This paper demonstrates the calibration and validation of the solar radiation model developed by Fu and Rich, employed within ArcGIS, with a focus on the input atmospheric parameters, diffusivity and transmissivity for the Netherlands. In addition, factors affecting the model’s performance with respect to the resolution of the input data were studied. Data were calibrated using ground measurements from Royal Netherlands Meteorological Institute (KNMI) stations in the Netherlands and validated with the station data from Cabauw. The results show that the default model values of diffusivity and transmissivity lead to substantial underestimation or overestimation of solar insolation. In addition, this paper also shows that calibration can be performed at different time scales depending on the purpose and spatial resolution of the input data.

scholarly journals Weekly water-loss from Spherical Water-loss Integrators on a Clearing and below Secondary Growth in Central Amazonia ()

1972 ◽  
Vol 2 (1) ◽  
pp. 33-36 ◽  
Author(s):  
W. L. F. Brinkmann
Keyword(s):  
Solar Radiation ◽  
Water Loss ◽  
Standing Crop ◽  
Secondary Growth ◽  
Tropical Agriculture ◽  
Air Humidity ◽  
Central Amazonia ◽  
Order Of Magnitude ◽  
Set Up ◽  
The Impact

Abstract: Spherical ceramic bulbs were set up as weekly water-loss integrators on a clearing and below a 2 year-old Cecropia-commumty at Km 18 of the Manaus-Itacoatiara Road. The instruments worked well in distinguishing the particular responses of individual sites to the impact of atmospheric agents as solar radiation, air temperature, air humidity and wind. Water-loss was primarily dependent on the order of magnitude of the weekly total of solar radiation and the presence or lack of a standing crop. Already a scarce secondary growth will reduce the weekly amount of water lost to the atmosphere considerably. Shelter-wood, however, considering the crop specific demands if introduced to tropical agriculture would provide favourable conditions as far as the impact of atmospheric controls on the tropical environment are concerned.

scholarly journals Solar simulated ultraviolet radiation inactivates HCoV-NL63 and SARS-CoV-2 coronaviruses at environmentally relevant doses

2021 ◽  
Author(s):  
Georg T. Wondrak ◽  
Jana Jandova ◽  
Spencer J. Williams ◽  
Dominik Schenten
Keyword(s):  
Gene Expression ◽  
Stress Response ◽  
Uv Light ◽  
Gene Expression Array ◽  
Array Analysis ◽  
Expression Array ◽  
Response Gene ◽  
Full Spectrum ◽  
Solar Uv ◽  
Stress Response Gene

The germicidal properties of short wavelength ultraviolet C (UVC) light are well established and used to inactivate many viruses and other microbes. However, much less is known about germicidal effects of terrestrial solar UV light, confined exclusively to wavelengths in the UVA and UVB regions. Here, we have explored the sensitivity of the human coronaviruses HCoV-NL63 and SARS-CoV-2 to solar-simulated full spectrum ultraviolet light (sUV) delivered at environmentally relevant doses. First, HCoV-NL63 coronavirus inactivation by sUV-exposure was confirmed employing (i) viral plaque assays, (ii) RT-qPCR detection of viral genome replication, and (iii) infection-induced stress response gene expression array analysis. Next, a detailed dose-response relationship of SARS-CoV-2 coronavirus inactivation by sUV was elucidated, suggesting a half maximal suppression of viral infectivity at low sUV doses. Likewise, extended sUV exposure of SARS-CoV-2 blocked cellular infection as revealed by plaque assay and stress response gene expression array analysis. Moreover, comparative (HCoV-NL63 versus SARS-CoV-2) single gene expression analysis by RT-qPCR confirmed that sUV exposure blocks coronavirus-induced redox, inflammatory, and proteotoxic stress responses. Based on our findings, we estimate that solar ground level full spectrum UV light impairs coronavirus infectivity at environmentally relevant doses. Given the urgency and global scale of the unfolding SARS-CoV-2 pandemic, these prototype data suggest feasibility of solar UV-induced viral inactivation, an observation deserving further molecular exploration in more relevant exposure models.

scholarly journals Effects of Solar UV Radiation on Morphology and Photosynthesis of Filamentous Cyanobacterium Arthrospira platensis

2005 ◽  
Vol 71 (9) ◽  
pp. 5004-5013 ◽  
Author(s):  
Hongyan Wu ◽  
Kunshan Gao ◽  
Virginia E. Villafañe ◽  
Teruo Watanabe ◽  
E. Walter Helbling
Keyword(s):  
Solar Radiation ◽  
Cell Density ◽  
Uv Radiation ◽  
Time Scales ◽  
Morphological Development ◽  
Filamentous Cyanobacterium ◽  
Solar Uv Radiation ◽  
Solar Uv ◽  
Adaptive Time ◽  
The Impact

ABSTRACT To study the impact of solar UV radiation (UVR) (280 to 400 nm) on the filamentous cyanobacterium Arthrospira (Spirulina) platensis, we examined the morphological changes and photosynthetic performance using an indoor-grown strain (which had not been exposed to sunlight for decades) and an outdoor-grown strain (which had been grown under sunlight for decades) while they were cultured with three solar radiation treatments: PAB (photosynthetically active radiation [PAR] plus UVR; 280 to 700 nm), PA (PAR plus UV-A; 320 to 700 nm), and P (PAR only; 400 to 700 nm). Solar UVR broke the spiral filaments of A. platensis exposed to full solar radiation in short-term low-cell-density cultures. This breakage was observed after 2 h for the indoor strain but after 4 to 6 h for the outdoor strain. Filament breakage also occurred in the cultures exposed to PAR alone; however, the extent of breakage was less than that observed for filaments exposed to full solar radiation. The spiral filaments broke and compressed when high-cell-density cultures were exposed to full solar radiation during long-term experiments. When UV-B was screened off, the filaments initially broke, but they elongated and became loosely arranged later (i.e., there were fewer spirals per unit of filament length). When UVR was filtered out, the spiral structure hardly broke or became looser. Photosynthetic O2 evolution in the presence of UVR was significantly suppressed in the indoor strain compared to the outdoor strain. UVR-induced inhibition increased with exposure time, and it was significantly lower in the outdoor strain. The concentration of UV-absorbing compounds was low in both strains, and there was no significant change in the amount regardless of the radiation treatment, suggesting that these compounds were not effectively used as protection against solar UVR. Self-shading, on the other hand, produced by compression of the spirals over adaptive time scales, seems to play an important role in protecting this species against deleterious UVR. Our findings suggest that the increase in UV-B irradiance due to ozone depletion not only might affect photosynthesis but also might alter the morphological development of filamentous cyanobacteria during acclimation or over adaptive time scales.

scholarly journals Photocatalytic Activity and Optical Properties of Blue Persistent Phosphors under UV and Solar Irradiation

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
C. R. García ◽  
L. A. Diaz-Torres ◽  
J. Oliva ◽  
M. T. Romero ◽  
P. Salas
Keyword(s):  
Photocatalytic Activity ◽  
Annealing Temperature ◽  
Uv Light ◽  
Solar Irradiation ◽  
Photoluminescence Spectra ◽  
X Ray Diffraction ◽  
X Ray ◽  
Water Cleaning ◽  
Different Temperatures ◽  
The Eu

Blue phosphorescent strontium aluminosilicate powders were prepared by combustion synthesis route and a postannealing treatments at different temperatures. X-ray diffraction analysis showed that phosphors are composed of two main hexagonal phases: SrAl2O4and Sr3Al32O51. The morphology of the phosphors changed from micrograins (1000°C) to a mixture of bars and hexagons (1200°C) and finally to only hexagons (1300°C) as the annealing temperature is increased. Photoluminescence spectra showed a strong blue-green phosphorescent emission centered atλem=455 nm, which is associated with4f65d1→4f6  (8S7/2)transition of the Eu2+. The sample annealed at 1200°C presents the highest luminance value (40 Cd/m2) with CIE coordinates (0.1589, 0.1972). Also, the photocatalytic degradation of methylene blue (MB) under UV light (at 365 nm) was monitored. Samples annealed at 1000°C and 1300°C presented the highest percentage of degradation (32% and 38.5%, resp.) after 360 min. In the case of photocatalytic activity under solar irradiation, the samples annealed at 1000°C, 1150°C, and 1200°C produced total degradation of MB after only 300 min. Hence, the results obtained with solar photocatalysis suggest that our powders could be useful for water cleaning in water treatment plants.

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