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Human physiology, hazards and health risks
Published in Stephen Battersby, Clay's Handbook of Environmental Health, 2023
Revati Phalkey, Naima Bradley, Alec Dobney, Virginia Murray, John O’Hagan, Mutahir Ahmad, Darren Addison, Tracy Gooding, Timothy W Gant, Emma L Marczylo, Caryn L Cox
Ultraviolet radiation (UVR) – This affects primarily the skin and the eye [22, 25]. The short-term skin effect is sunburn, which may be followed by increased production of melanin (suntan), and which only offers minimal protection against further exposure. Acute ocular exposure to UVR can lead to photokeratitis and photoconjunctivitis (arc eye, snow blindness). Large doses of ultraviolet-A radiation can damage the retina, although this is not common as the lens and cornea tend to absorb the energy. Children are at particular risk as their eyes transmit much more of the UV-A component (which has a longer wavelength and is more penetrating through body tissues) to the retina than in older people. The principal long-term effect to the eye is the production of lens opacities – cataracts.
Radiation Hazards
Published in Dag K. Brune, Christer Edling, Occupational Hazards in the Health Professions, 2020
Eye — The main clinical effects of UV on the eye are photokeratitis and conjunctivitis, which appear 2 to 24 h after irradiation. The symptoms are acute hyperemia, photophobia, and blepharospasm, which last from 1 to 5 d. In general, there is no residual lesion. Photokeratitis is caused preferentially by UV-B, but is also caused by UV-A, though with decreasing sensitivity. The peak sensitivity of the cornea appears at wavelengths of 270 or 288 nm. The effect depends on the total energy absorbed. The threshold has a minimum at 270 nm of 50 J/m2, rising to 550 J/m2 at 310 nm, and followed by a steep increase to 22,500 J/m2 at 315 nm.
Safety and Hygiene
Published in Jiri George Drobny, Radiation Technology for Polymers, 2020
The biological effects of UV radiation result mostly from exposure to wavelengths below 325 nm and resemble the typical syndromes of sunburn, such as skin reddening (erythema), skin burning, dryness, premature aging, and pigmentation. Eyes may be also affected by developing inflammation, pain, photophobia, tearing, temporary blindness, and cataracts.1 The eyes are most sensitive to UV radiation from 210 nm (UVC and UVB). Maximum absorption by the cornea occurs around 280 nm. Absorption of UVA in the lens may be a factor in producing cataracts (clouding of the lens in the eye). Acute overexposure of the eye to UV radiation can cause photokeratitis (inflammation of the cornea) and photoconjunctivitis (inflammation of the cornea, more commonly known as “snow blindness” or “welders’ flash”). Symptoms range from mild irritation to severe pain and, in an extreme case, to irreversible damage.2
Field study of early implementation of UV sources and their relative effectiveness for public health and safety
Published in Journal of Occupational and Environmental Hygiene, 2022
Jennifer Henderson, Ben Ma, Martin Cohen, Joel Dazey, John Scott Meschke, Karl G. Linden
All UVGI devices installed at the Space Needle advertised UVC or far UVC radiation emission wavelengths. UVC is a classification of UV that includes wavelengths from 200 to 280 nanometers (nm) (IES 2020). UVC has been recognized as an effective germicidal disinfectant but is also known to be hazardous to exposed human skin and eyes. UVC overexposure to the skin can cause erythema or sunburn while overexposure to the eye can result in photokeratitis, a painful condition of the eye (LBNL 2018). Far UVC, increasing in popularity and interest for its germicidal properties, is part of the UVC band that encompasses wavelengths in the range of 200–225 nm. Far UVC has demonstrated disinfection efficacy, yet studies suggest that these wavelengths do not cause human health issues typically associated with UVC exposure (Simons et al. 2020).