Dosimeter for measurement of UVA exposures (original) (raw)

Potential of phenothiazine as a thin film dosimeter for UVA exposures

Photochemical & Photobiological Sciences, 2005

The research reported in this paper on the changes in absorbance and the calibration of a proposed UVA (320-400 nm) dosimeter have established the phenothiazine/mylar combination as a potential UVA dosimeter for population studies of UVA exposures. The change in optical absorbance at 370 nm was employed to quantify the UVA exposures. This change starts to saturate at approximately 0.3. This relates to solar UVA exposures at a sub-tropical site on a horizontal plane of approximately three to four hours. The shape of this calibration curve varies with the season. This can be overcome in the same manner as for polysulphone where the dosimeter is calibrated for the conditions that it will be employed to measure the UVA exposures.

Development and characterisation of an ultra-long exposure UV dosimeter

2014

Excessive exposure to solar ultraviolet (UV) radiation is known to have detrimental effects on human health, some of which are cumulative in nature with impacts that may arise after years and decades of exposure. Therefore, it is important that the risk associated with prolonged UV exposure can be investigated; this requires long-term studies in which large-dose measurements can be accurately quantified. Chemically-based UV dosimeters have been widely used to measure personal UV exposure since 1976. Despite the development of electronic UV dosimeters, chemical dosimeters maintain their suitability in human exposure research as versatile, labour- and cost-effective UV monitors that require no power. The main limitation of existing chemical dosimeters is their short dynamic measurement range, as they are saturated after relatively short exposure times. Consequently, prolonged personal UV exposures are estimated either from measurements spanning just a few days, with high uncertainty, ...

A Critical Assessment of Two Types of Personal UV Dosimeters

Photochemistry and Photobiology, 2011

Doses of erythemally weighted irradiances derived from polysulphone (PS) and electronic ultraviolet (EUV) dosimeters have been compared with measurements obtained using a reference spectroradiometer. PS dosimeters showed mean absolute deviations of 26% with a maximum deviation of 44%, the calibrated EUV dosimeters showed mean absolute deviations of 15% (maximum 33%) around noon during several test days in the northern hemisphere autumn. In the case of EUV dosimeters, measurements with various cutoff filters showed that part of the deviation from the CIE erythema action spectrum was due to a small, but significant sensitivity to visible radiation that varies between devices and which may be avoided by careful preselection. Usually the method of calibrating UV sensors by direct comparison to a reference instrument leads to reliable results. However, in some circumstances the quality of measurements made with simple sensors may be overestimated. In the extreme case, a simple pyranometer can be used as a UV instrument, providing acceptable results for cloudless skies, but very poor results under cloudy conditions. It is concluded that while UV dosimeters are useful for their design purpose, namely to estimate personal UV exposures, they should not be regarded as an inexpensive replacement for meteorological grade instruments.

Use of Electronic UV Dosimeters in Measuring Personal UV Exposures and Public Health Education

Atmosphere, 2020

The performance limits of electronic ultraviolet (EUV) dosimeters, which use AlGaN Schottky photodiodes as the ultraviolet radiation (UVR) sensing element to measure personal erythemally weighted UVR exposures, were investigated via a direct comparison with meteorological-grade reference instruments. EUV dosimeters with two types of AlGaN Schottky photodiode were compared to second-generation ‘Robertson–Berger type’ broadband erythemal radiometers. This comparison was done by calculating correction factors for the deviations of the spectral responsivity of each instrument from the CIE erythemal action spectrum and for deviations in their angular response from the ideal cosine response of flat surfaces and human skin. Correction factors were also calculated to convert the output of these instruments to vitamin D-weighted UV irradiances. These comparisons showed that EUV dosimeters can be engineered with spectral responsivities and cosine response errors approaching those of Robertson...

SUNTEST: a chemical UVB radiation dosimeter

Journal of Photochemistry and Photobiology B: Biology, 1995

A simple disposable chemical UVB radiation dosimeter with silver-mercury--oxalate suspension, SUNTEST, was developed for use by the general public. Its spectral sensitivity curve closely matches the erythemal action spectrum. SUNTEST takes account of the variables influencing the length of sunbathing. The dose of solar UV radiation can be evaluated from the darkening of the dosimeter, from white to dark brown. On the basis of the results of a 5 rain exposure, recommendations are given for safe exposure times (which do not produce sunburn) for different skin types. Regular use of this simple UVB dosimeter will contribute to the prevention of acute adverse effects of solar exposure; like any limitation of UV exposures, it may be expected to reduce also the late adverse effects, including skin malignancies.

Measurement of UVA Exposure to Solar Radiation

Photochemistry and Photobiology, 1996

Exposure to solar UVA (320-400 nm) radiation can damage DNA and lead to skin disorders. Conventional dosimetry using a single piece of polysulfone or diglycol carbonate (CR-39) cannot provide accurate measurement of the biologically effective irradiance for erythema for the UVA waveband. A package employing four dosimeters (polysulfone, nalidixic acid, 8-methoxypsoralen and phenothiazine) has been shown to be effective for use as a spectrum evaluator for evaluating the UVA source spectrum. In Brisbane, on a horizontal position, the spectrum evaluator requires about 5 min exposure in summer and about 20 min in winter. This amounts to about 10 mJ cm-2 of erythema1 UV radiation.

Biological and physical dosimeters for monitoring solar UV-B light

Journal of Radiation Research, 1990

A biological dosimetry system for measuring solar UV-B light was established using bacteriophage T1 with E. coli Bs-1 as the host cell. Also a new physical UV-B dosimeter was developed which can specifically detect the UV spectral region related to inactivation of phage T1. Phage T1 is very stable in liquid suspension and it has adequate sensitivity to measure the intensity of solar UV-B. In addition, the survival of phage T1 responded linearly to UV fluences when plotted semi-logarithmic ally. Thus T1 seemed to have characteristic features making it suitable material as a biological dosimeter for sunlight. Outdoor experiments throughout one year showed that the mean amount of solar UV light in summer was about 6 fold larger than that in winter at Isehara (139.5 degrees E, 35.5 degrees N), Japan. A novel physical dosimeter which responds faithfully to UV-B light under atmospheric conditions on the ground was developed as well. The spectral response was very close to that of biological materials. Readings of this UV-B dosimeter could be converted into the efficiency of sunlight upon biological materials. This instrument is compact; it can also be used as an erythemal dosimeter.

Actinic ultraviolet exposures to humans assessed with a dosimetric technique

International Journal of Environmental Health Research, 1999

A spectrum evaluator based on a system of four materials has been applied to the evaluation of actinic ultraviolet exposures to humans. The exposures were evaluated between early morning and near noon in summer and the actinic irradiances calculated ranged from 3 μW cm -2 to 5 μW cm -2 . Simultaneously, the broad band irradiances which induced the actinic exposures and/or the biologically effective exposures for any other process may be evaluated with the method. The erythemal exposures ranged from 13 to 23 μW cm -2 . The method can be useful both for solar UV studies and research with UV lamps which possess radiation wavelengths shorter than 295 nm where the actinic and erythemal action spectra differ significantly.

AN EVALUATION OF NALIDIXIC ACID FILM AS A UV-A RADIATION DOSIMETER

Photochemistry and Photobiology, 1983

Nalidixic Acid (NA)' incorporated into a polyvinyl chloride film has recently been proposed as a UV-A radiation dosimeter. A trial. in which two different batches of NA film were exposed to both solar simulating and monochromatic 330 nm radiation is described. With both batches o f film a linear relationship was observed between the UV-A fluence derived from the NA film and the Huence determined with conventional electronic radiometric equipment. There was, however. considerablc hatch variation in response to UV-A radiation. Corrections may be made for batch differences. If the batch response can be standardized. our results would support the use of NA film as a simple routine method of measuring UV-A radiation