Ultraviolet radiation (UVR) exposure is known to cause serious effects such as conjunctivitis and keratitis in eyes and erythema in skin. The exposure assessment of UVR has not been well established and developed in workplaces due to the lack of suitable UV detecting instruments. Therefore, UV monitoring and measuring procedures were investigated and developed with commercial spectroradiometry devices described in this paper. The UVR irradiance integrated with a biological effective parameter (S lambda) represents the impacts on human skin and eyes as UV effective irradiance. The spectral weighting function derived from the American Conference of Governmental Industrial Hygienists was applied and evaluated to indicate the degree of harmfulness of UVR as a function of wavelength. A portable UV germicidal lamp with short and long wavelengths (254 nm and 365 nm) served as the UVR emission source. The UVR photon count similar to the perceived brightness of a source, irradiance, and effective irradiance (E eff) of the germicidal lamp were measured and analyzed, then the permissible exposure times (T max) were derived for UVR exposure assessment. This monitoring provided a comprehensive approach to detecting UVR magnitude, evaluated the performance of the approach, and quantified the effective exposure based on measured data. From this study, the methodology of UV measurement was established and could be applied to further UVR exposure assessment in the workplace.
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http://dx.doi.org/10.1097/01.HP.0000248124.50985.0a | DOI Listing |
Photochem Photobiol
January 2025
Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, Maharashtra, India.
Virus-laden aerosols play a substantial role in the spread of numerous infectious diseases, particularly in enclosed indoor settings. Ultraviolet-C (UVC) disinfection is known to be a highly efficient method for disinfecting pathogenic airborne viruses. Recent recommendations suggest using far-UVC radiation (222 nm) emitted by KrCl* (krypton-chloride) excimer lamps to disinfect high-risk public spaces due to lower exposure risks than low-pressure (LP) mercury lamps (254 nm).
View Article and Find Full Text PDFPhotochem Photobiol
December 2024
Department of Ophthalmology, Shimane University Faculty of Medicine, Izumo, Japan.
The ocular safety of 222-nm far-ultraviolet-C (UV-C) irradiation, widely recognized for its germicidal properties, was evaluated in a clinical setting to assess its long-term health effects on the human eye. This prospective observational study involved a 36-month follow-up of physicians working in an ophthalmic examination room equipped with 222-nm UV-C lamps. Initially, a 12-month observation showed no signs of acute or chronic ocular damage.
View Article and Find Full Text PDFJ Hazard Mater
November 2024
School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong; Department of Architecture and Civil Engineering, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong. Electronic address:
Ultraviolet germicidal irradiation (UVGI) technology can inhibit the environmental transmission of airborne pathogens, but the dose-response behavior of airborne human coronavirus and wavelength-specific inactivation mechanisms are not well understood. This study investigated three competitive UVC sources for their inactivation efficacy and mechanisms against human coronavirus OC43 (HCoV-OC43). Results showed the following order of inactivation efficacy: 222-nm KrCl excimer lamp > 263-nm UV-LEDs > 254-nm low-pressure mercury lamp.
View Article and Find Full Text PDFEnviron Sci Technol
November 2024
Department of Biological and Chemical Engineering, Aarhus University, Aarhus C 8000, Denmark.
Germicidal ultraviolet lamps with a peak emission at 222 nm (GUV222) are gaining prominence as a safe and effective solution to reduce disease transmission in occupied indoor environments. While previous studies have reported O production from GUV222, less is known about their impact on other indoor constituents affecting indoor air quality, especially in real occupied environments. In this study, the effects of GUV222 on the levels of ozone (O), ultrafine particles (UFPs), and volatile organic compounds (VOCs) were investigated across multiple offices with varying occupancies.
View Article and Find Full Text PDFJ Environ Health Sci Eng
December 2024
Faculty of Engineering, Built Environment & IT, SEGi University, Petaling Jaya, 47810 Selangor Malaysia.
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 254 nm wavelength has been proven for its disinfection efficacy; however, its usage is limited to unoccupied conditions due to the risk of ultraviolet exposure.
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