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Marro M, Moccozet L, Vernez D. Assessing Human Eye Exposure to UV Light: A Narrative Review. Front Public Health 2022; 10:900979. [PMID: 35875046 PMCID: PMC9300719 DOI: 10.3389/fpubh.2022.900979] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 04/22/2022] [Indexed: 11/13/2022] Open
Abstract
Exposure to ultraviolet light is associated with several ocular pathologies. Understanding exposure levels and factors is therefore important from a medical and prevention perspective. A review of the current literature on ocular exposure to ultraviolet light is conducted in this study. It has been shown that ambient irradiance is not a good indicator of effective exposure and current tools for estimating dermal exposure have limitations for the ocular region. To address this, three methods have been developed: the use of anthropomorphic manikins, measurements through wearable sensors and numerical simulations. The specific objective, limitations, and results obtained for the three different methods are discussed.
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Affiliation(s)
- Michele Marro
- Computer Science Center, University of Geneva, Geneva, Switzerland
| | - Laurent Moccozet
- Computer Science Center, University of Geneva, Geneva, Switzerland
| | - David Vernez
- Center for Public Health and Primary Care Medicine (Unisanté), University of Lausanne, Lausanne, Switzerland
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Wang Y, Lou J, Ji Y, Wang Z. Increased photokeratitis during the coronavirus disease 2019 pandemic: Clinical and epidemiological features and preventive measures. Medicine (Baltimore) 2021; 100:e26343. [PMID: 34128883 PMCID: PMC8213321 DOI: 10.1097/md.0000000000026343] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2020] [Accepted: 05/28/2021] [Indexed: 01/04/2023] Open
Abstract
An increased incidence of photokeratitis has occurred during the coronavirus disease 2019 (COVID-19) pandemic due to improper and unprotected use of ultraviolet lamps. Here, we summarize the clinical and epidemiological features of this increased incidence of photokeratitis and share advice in using health education to prevent it.We collected data from patients diagnosed with photokeratitis from October 7, 2019 to December 1, 2019, and from February 17, 2020 to April 12, 2020, and compared the frequency of onset, site of ultraviolet radiation (UVR) exposure, reason for exposure, exposure time, and recovery time. We also implemented and evaluated multiple measures of public health education to prevent increased disease.After the COVID-19 outbreak, the frequency of onset of photokeratitis increased significantly, especially among young women. The main reason for UVR exposure changed from welding to disinfection. The incidence sites varied, and the exposure time was longer. As a result, patients needed a longer time to recover. Positive health education was an useful and convenient measure to prevent the disease.While the COVID-19 pandemic is ongoing, more attention should be paid to public health and implement positive measures to prevent photokeratitis.
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Affiliation(s)
| | - Jing Lou
- Suzhou Dushuhu Public Hospital, Suzhou, Jiangsu, China
| | - Ye Ji
- The First Affiliated Hospital of Soochow University
| | - ZhenYu Wang
- The First Affiliated Hospital of Soochow University
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Corneal UV Protective Effects of a Topical Antioxidant Formulation: A Pilot Study on In Vivo Rabbits. Int J Mol Sci 2020; 21:ijms21155426. [PMID: 32751471 PMCID: PMC7432813 DOI: 10.3390/ijms21155426] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 07/27/2020] [Accepted: 07/27/2020] [Indexed: 01/10/2023] Open
Abstract
This study aimed to evaluate the protective effect of a topical antioxidant and ultraviolet (UV) shielding action formulation containing riboflavin and D-α-tocopherol polyethylene glycol succinate (TPGS) vitamin E against corneal UV-induced damage in vivo rabbit eyes. In vivo experiments were performed using male albino rabbits, which were divided into four groups. The control group (CG) did not receive any UV irradiation; the first group (IG) was irradiated with a UV-B−UV-A lamp for 30 min; the second (G30) and third (G60) groups received UV irradiation for 30 and 60 min, respectively, and were topically treated with one drop of the antioxidant and shielding formulation every 15 min, starting one hour before irradiation, until the end of UV exposure. The cornea of the IG group showed irregular thickening, detachment of residual fragments of the Descemet membrane, stromal fluid swelling with consequent collagen fiber disorganization and disruption, and inflammation. The cornea of the G30 group showed edema, a mild thickening of the Descemet membrane without fibrillar collagen disruption and focal discoloration, or inflammation. In the G60 group, the cornea showed a more severe thickening, a more abundant fluid accumulation underneath the Descemet membrane with focal detachment, and no signs of severe tissue alterations, as were recorded in the IG group. Our results demonstrate that topical application of eye drops containing riboflavin and TPGS vitamin E counteracts UV corneal injury in exposed rabbits.
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Dibowski G, Esser K. Hazards Caused by UV Rays of Xenon Light Based High Performance Solar Simulators. Saf Health Work 2017; 8:237-245. [PMID: 28951799 PMCID: PMC5605898 DOI: 10.1016/j.shaw.2016.12.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Revised: 02/22/2016] [Accepted: 12/13/2016] [Indexed: 11/28/2022] Open
Abstract
Background Solar furnaces are used worldwide to conduct experiments to demonstrate the feasibility of solar–chemical processes with the aid of concentrated sunlight, or to qualify high temperature-resistant components. In recent years, high-flux solar simulators (HFSSs) based on short-arc xenon lamps are more frequently used. The emitted spectrum is very similar to natural sunlight but with dangerous portions of ultraviolet light as well. Due to special benefits of solar simulators the increase of construction activity for HFSS can be observed worldwide. Hence, it is quite important to protect employees against serious injuries caused by ultraviolet radiation (UVR) in a range of 100 nm to 400 nm. Methods The UV measurements were made at the German Aerospace Center (DLR), Cologne and Paul-Scherrer-Institute (PSI), Switzerland, during normal operations of the HFSS, with a high-precision UV-A/B radiometer using different experiment setups at different power levels. Thus, the measurement results represent UV emissions which are typical when operating a HFSS. Therefore, the biological effects on people exposed to UVR was investigated systematically to identify the existing hazard potential. Results It should be noted that the permissible workplace exposure limits for UV emissions significantly exceeded after a few seconds. One critical value was strongly exceeded by a factor of 770. Conclusion The prevention of emissions must first and foremost be carried out by structural measures. Furthermore, unambiguous protocols have to be defined and compliance must be monitored. For short-term activities in the hazard area, measures for the protection of eyes and skin must be taken.
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Affiliation(s)
- Gerd Dibowski
- German Aerospace Center (DLR e.V.), Institute of Solar Research, Cologne, Germany
| | - Kai Esser
- German Aerospace Center (DLR e.V.), Institute of Solar Research, Cologne, Germany
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Yu J, Hua H, Liu Y, Liu Y. Distributions of Direct, Reflected, and Diffuse Irradiance for Ocular UV Exposure at Different Solar Elevation Angles. PLoS One 2016; 11:e0166729. [PMID: 27846278 PMCID: PMC5112793 DOI: 10.1371/journal.pone.0166729] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Accepted: 11/02/2016] [Indexed: 11/18/2022] Open
Abstract
To analyze intensities of ocular exposure to direct (Eo,dir), reflected (Eo,refl), and diffuse (Eo,diff) ultraviolet (UV) irradiance at different solar elevation angles (SEAs), a rotating manikin and dual-detector spectrometer were used to monitor the intensity of ocular exposure to UV irradiation (Eo) and ambient UV radiation (UVR) under clear skies in Sanya, China. Eo,dir was derived as the difference between maximum and minimum measured Eo values. Eo,refl was converted from the value measured at a height of 160 cm. Eo,diff was calculated as the minimum measured Eo value minus Eo,refl. Regression curves were fitted to determine distributions of intensities and growth rates at different wavelengths and SEAs. Eo,dir differed from ambient UVR exposure. Linear, quadratic, and linear Eo,dir distributions were obtained in SEA ranges of 14°–30°, 30°–50°, and 50°–90°, respectively, with maximum Eo,dir at 32°–38° SEA. Growth rates of Eo,dir with increasing wavelength were fitted with quadratic functions in all SEA ranges. Distributions and growth rate of Eo,refl values were fitted with quadratic functions. Maximum Eo,diff was achieved at the same SEA for all fitted quadratic functions. Growth rate of Eo,diff with increasing wavelength was fitted with a linear function. Eo,dir distributions were fitted with linear or quadratic functions in different SEA ranges. All Eo,refl and Eo,diff distributions were fitted with quadratic functions. As SEA increased, the Eo,dir portion of Eo increased and then decreased; the Eo,refl portion increased from an initial minimum; and the Eo,diff portion first decreased and then increased. The findings may provide data supporting on construction of a mathematical model of ocular UV exposure.
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Affiliation(s)
- Jiaming Yu
- Ophthalmology Department, the Fourth Affiliated Hospital of China Medical University, Shenyang, Liaoning, China
| | - Hui Hua
- School of Public Health, China Medical University, Shenyang, Liaoning, China
| | - Yan Liu
- Department of Biomedical Engineering, China Medical University, Shenyang, China
| | - Yang Liu
- School of Public Health, China Medical University, Shenyang, Liaoning, China
- * E-mail:
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Tanaka Y, Nakayama J. Upregulated epidermal growth factor receptor expression following near-infrared irradiation simulating solar radiation in a three-dimensional reconstructed human corneal epithelial tissue culture model. Clin Interv Aging 2016; 11:1027-33. [PMID: 27536083 PMCID: PMC4975136 DOI: 10.2147/cia.s111530] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Background and objective Humans are increasingly exposed to near-infrared (NIR) radiation from both natural (eg, solar) and artificial (eg, electrical appliances) sources. Although the biological effects of sun and ultraviolet (UV) exposure have been extensively investigated, the biological effect of NIR radiation is still unclear. We previously reported that NIR as well as UV induces photoaging and standard UV-blocking materials, such as sunglasses, do not sufficiently block NIR. The objective of this study was to investigate changes in gene expression in three-dimensional reconstructed corneal epithelial tissue culture exposed to broad-spectrum NIR irradiation to simulate solar NIR radiation that reaches human tissues. Materials and methods DNA microarray and quantitative real-time polymerase chain reaction analysis were used to assess gene expression levels in a three-dimensional reconstructed corneal epithelial model composed of normal human corneal epithelial cells exposed to water-filtered broad-spectrum NIR irradiation with a contact cooling (20°C). The water-filter allowed 1,000–1,800 nm wavelengths and excluded 1,400–1,500 nm wavelengths. Results A DNA microarray with >62,000 different probes showed 25 and 150 genes that were up- or downregulated by at least fourfold and twofold, respectively, after NIR irradiation. In particular, epidermal growth factor receptor (EGFR) was upregulated by 19.4-fold relative to control cells. Quantitative real-time polymerase chain reaction analysis revealed that two variants of EGFR in human corneal epithelial tissue were also significantly upregulated after five rounds of 10 J/cm2 irradiation (P<0.05). Conclusion We found that NIR irradiation induced the upregulated expression of EGFR in human corneal cells. Since over half of the solar energy reaching the Earth is in the NIR region, which cannot be adequately blocked by eyewear and thus can induce eye damage with intensive or long-term exposure, protection from both UV and NIR radiation may prevent changes in gene expression and in turn eye damage.
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Affiliation(s)
- Yohei Tanaka
- Department of Plastic Surgery, Clinica Tanaka Plastic, Reconstructive Surgery and Anti-aging Center; Department of Molecular Pathology, Shinshu University Graduate School of Medicine, Matsumoto, Nagano, Japan
| | - Jun Nakayama
- Department of Molecular Pathology, Shinshu University Graduate School of Medicine, Matsumoto, Nagano, Japan
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Liou JC, Teng MC, Tsai YS, Lin EC, Chen BY. UV-blocking spectacle lens protects against UV-induced decline of visual performance. Mol Vis 2015; 21:846-56. [PMID: 26283865 PMCID: PMC4527595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Accepted: 08/04/2015] [Indexed: 11/03/2022] Open
Abstract
PURPOSE Excessive exposure to sunlight may be a risk factor for ocular diseases and reduced visual performance. This study was designed to examine the ability of an ultraviolet (UV)-blocking spectacle lens to prevent visual acuity decline and ocular surface disorders in a mouse model of UVB-induced photokeratitis. METHODS Mice were divided into 4 groups (10 mice per group): (1) a blank control group (no exposure to UV radiation), (2) a UVB/no lens group (mice exposed to UVB rays, but without lens protection), (3) a UVB/UV400 group (mice exposed to UVB rays and protected using the CR-39™ spectacle lens [UV400 coating]), and (4) a UVB/photochromic group (mice exposed to UVB rays and protected using the CR-39™ spectacle lens [photochromic coating]). We investigated UVB-induced changes in visual acuity and in corneal smoothness, opacity, and lissamine green staining. We also evaluated the correlation between visual acuity decline and changes to the corneal surface parameters. Tissue sections were prepared and stained immunohistochemically to evaluate the structural integrity of the cornea and conjunctiva. RESULTS In blank controls, the cornea remained undamaged, whereas in UVB-exposed mice, the corneal surface was disrupted; this disruption significantly correlated with a concomitant decline in visual acuity. Both the UVB/UV400 and UVB/photochromic groups had sharper visual acuity and a healthier corneal surface than the UVB/no lens group. Eyes in both protected groups also showed better corneal and conjunctival structural integrity than unprotected eyes. Furthermore, there were fewer apoptotic cells and less polymorphonuclear leukocyte infiltration in corneas protected by the spectacle lenses. CONCLUSIONS The model established herein reliably determines the protective effect of UV-blocking ophthalmic biomaterials, because the in vivo protection against UV-induced ocular damage and visual acuity decline was easily defined.
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Affiliation(s)
- Jyh-Cheng Liou
- Department of Ophthalmology, Chung Shan Medical University Hospital, Taichung, Taiwan,School of Optometry, Chung Shan Medical University, Taichung, Taiwan,Institute of Medicine, Chung Shan Medical University, Taichung, Taiwan
| | - Mei-Ching Teng
- Department of Ophthalmology, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - Yun-Shan Tsai
- Department of Ophthalmology, Chung Shan Medical University Hospital, Taichung, Taiwan,School of Optometry, Chung Shan Medical University, Taichung, Taiwan
| | - En-Chieh Lin
- Department of Ophthalmology, Chung Shan Medical University Hospital, Taichung, Taiwan,School of Optometry, Chung Shan Medical University, Taichung, Taiwan
| | - Bo-Yie Chen
- Department of Ophthalmology, Chung Shan Medical University Hospital, Taichung, Taiwan,School of Optometry, Chung Shan Medical University, Taichung, Taiwan
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Das P, Gokani A, Bagchi K, Bhaduri G, Chaudhuri S, Law S. Limbal epithelial stem-microenvironmental alteration leads to pterygium development. Mol Cell Biochem 2015; 402:123-39. [PMID: 25559558 DOI: 10.1007/s11010-014-2320-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Accepted: 12/23/2014] [Indexed: 12/13/2022]
Abstract
Maintenance of tissue homeostasis relies on the accurate regulation of tissue specific stem cell activity which is governed by the dynamic interaction between the positive and negative feedback modulating mechanism of stem cell microenvironmental niche. Alteration or deregulation of the "stem-microenvironmental networking" provokes disease development. Limbal epithelial stem cells (LESC) are the initiator hierarchy that maintains corneal integrity. Compartmentalization of LESC within the limbal vicinity provides an opportunity to understand the stem-microenvironmental relationship. The purpose of this study was to determine the microenvironmental alteration associated with LESCs fate in pterygium condition in comparison with healthy state. Clinical observations evaluated the ocular surface disorder with respect to corneal vascularization, tear film abnormality, and thickening of limbal area in pterygium patients. Structural alteration of limbal stem/progenitor cells and its neighboring niche components were observed using histology and scanning electron microscopy. Receptor overexpression of TGFβ-R1, EGF-R1, and IL6-Rα and alteration of IL2-Rα expression pointed toward aberration of "stem-microenvironmental networking" in the limbal vicinity during disease development. Increased cell proliferation index along with TERT, Cyclin-D1, and PCNA over-expression in limbal part of pterygium epithelial cells indicated increased cellular proliferation and disturbed homeostatic equilibrium. We postulate that pterygium is associated with limbal microenvironmental anomaly where the resident epithelial cells became hyperproliferative.
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Affiliation(s)
- Prosun Das
- Stem Cell Research and Application Unit, Department of Biochemistry and Medical Biotechnology, Calcutta School of Tropical Medicine, 108 C R Avenue, Kolkata, 700073, India
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Lucas RM, Norval M, Neale RE, Young AR, de Gruijl FR, Takizawa Y, van der Leun JC. The consequences for human health of stratospheric ozone depletion in association with other environmental factors. Photochem Photobiol Sci 2015; 14:53-87. [DOI: 10.1039/c4pp90033b] [Citation(s) in RCA: 101] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Ozone depletion, climate and human health.
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Affiliation(s)
- R. M. Lucas
- National Centre for Epidemiology and Population Health
- The Australian National University
- Canberra 2601
- Australia
- Telethon Kids Institute
| | - M. Norval
- Biomedical Sciences
- University of Edinburgh Medical School
- Edinburgh EH8 9AG
- UK
| | - R. E. Neale
- QIMR Berghofer Medical Research Institute
- Brisbane 4029
- Australia
| | - A. R. Young
- King's College London (KCL)
- St John's Institute of Dermatology
- London SE1 9RT
- UK
| | - F. R. de Gruijl
- Department of Dermatology
- Leiden University Medical Centre
- NL-2300 RC Leiden
- The Netherlands
| | - Y. Takizawa
- Akita University Graduate School of Medicine
- Akita Prefecture
- Japan
- National Institute for Minamata Diseases
- Kumamoto Prefecture
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Liu GC, Wang F, Gao YY, Yang Z, Hu LW, Gao Q, Ri JC, Liu Y. The enhancement of biological ocular UV radiation on beaches compared to the radiation on grass. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2014; 141:106-12. [PMID: 25463657 DOI: 10.1016/j.jphotobiol.2014.09.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Revised: 09/07/2014] [Accepted: 09/08/2014] [Indexed: 11/25/2022]
Abstract
BACKGROUND The influence of albedo on ocular UV exposure has seldom been reported. This paper aimed to explore the enhancement effect on measured ocular UV radiation due to a sand surface compared to measured ocular UV radiation due to a grass surface. METHODS We measured ambient and ocular UV radiation over the beach and grass surface in Sanya City of China (18.4°N, 109.7°E). The experimental apparatus was composed of a manikin and a dual-detector spectrometer. Integration of both UVA and UVB radiation was used to denote UV radiation. Then biologically effective ocular UVB radiation (UVBE) and the ratios of UVBE of two surfaces were calculated. RESULT Maximum of ocular UV radiation versus time over the two surfaces is bimodal. UVBE on the beach is significantly larger than UVBE on the sand, and UVBE peaked at different solar elevation angle (SEA) over the two surfaces (about 53° and 40° on the beach and grass, respectively, according to Bayesian regression). The maximum of ocular UVBE ratios is greater than two, which peaked SEA was about 50°. One hour's cumulative radiation under sunny weather exceeds thresholds for photokeratitis, conjunctivitis and lens damage. CONCLUSIONS Higher albedo significantly increased biological ocular UV radiation. Tourists on tropical beaches should take protective measures and avoid facing the sun directly, especially when SEA is around 50°.
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Affiliation(s)
- Guang-Cong Liu
- School of Public Health, China Medical University, No. 92 Bei'er Road, Heping District, Shenyang 110001, Liaoning, PR China
| | - Fang Wang
- School of Public Health, China Medical University, No. 92 Bei'er Road, Heping District, Shenyang 110001, Liaoning, PR China
| | - Yan-Yan Gao
- School of Public Health, China Medical University, No. 92 Bei'er Road, Heping District, Shenyang 110001, Liaoning, PR China
| | - Zheng Yang
- School of Public Health, China Medical University, No. 92 Bei'er Road, Heping District, Shenyang 110001, Liaoning, PR China
| | - Li-Wen Hu
- School of Public Health, China Medical University, No. 92 Bei'er Road, Heping District, Shenyang 110001, Liaoning, PR China
| | - Qian Gao
- School of Public Health, China Medical University, No. 92 Bei'er Road, Heping District, Shenyang 110001, Liaoning, PR China
| | - Jun-Chol Ri
- School of Public Health, China Medical University, No. 92 Bei'er Road, Heping District, Shenyang 110001, Liaoning, PR China
| | - Yang Liu
- School of Public Health, China Medical University, No. 92 Bei'er Road, Heping District, Shenyang 110001, Liaoning, PR China.
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Might outdoor heat stress be considered a proxy for the unperceivable effect of the ultraviolet-induced risk of erythema in Florence? JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2014; 130:338-48. [PMID: 24423784 DOI: 10.1016/j.jphotobiol.2013.12.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Revised: 12/13/2013] [Accepted: 12/16/2013] [Indexed: 11/23/2022]
Abstract
Erythema is the most familiar short-term symptom of human skin associated with overexposure to unperceivable ultraviolet radiation (UV). However, people are able to perceive the warm infrared component of the solar radiation by means of thermal (dis)comfort. This study investigated the potentiality of perceived outdoor heat stress as a valuable proxy for the unperceivable effect of UV-induced risk of erythema in a Mediterranean city. Meteorological data and UVB (280-320nm) measurements were obtained for the 2004-2012 period by a weather station located in the municipality of Florence. Continuous measurements of erythemally effective UV (UVEry) were performed by means of a broadband temperature-corrected radiometer with the spectral response close to the erythemal action spectrum. Hourly UVEry doses were expressed as Standard Erythemal Doses (SEDs). The newly developed Universal Thermal Climate Index (UTCI), that represents the state-of-the-art of outdoor thermal (dis)comfort evaluation, was also assessed. Descriptive analyses of the hourly distribution per month of the frequencies of days with heat stress and UVEry exceeding 2.0, 3.0, 4.5 and 6.0 SEDs were carried out based on the general skin-type characteristics. The association between UVEry and UTCI was analyzed by a two-way contingency table approach. The probability of UVEry exceeding specific SED thresholds when heat stress occurs was often significantly higher than the same probability when no heat stress is perceived. Furthermore, increased magnitudes of the ratios, ranging from the very sensitive to the minimally sensitive skin types, were also found. However, during several months, too many days occur without any signs of heat discomfort, even when people may be exposed to relevant doses of harmful UVEry for the skin of various phototypes. These findings underlie the need for public health authorities to provide differentiated advice per month in relation to potential UV skin damage in the city of Florence.
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