Estimation of Individual Exposure to Erythemal Weighted UVR by Multi-Sensor Measurements and Integral Calculation

Assessing playgrounds ultraviolet radiation (UVR) environments in College Station, Texas: Creating UVR-safe environments for children

The design of playground environments significantly influences children's exposure to Ultraviolet Radiation (UVR), which impacts long-term health. Excessive UVR exposure can lead to serious health issues such as skin cancer. Adequate UVR is crucial for vitamin D synthesis, which supports cardiovascular and skeletal development. This study evaluates the effectiveness of current playground designs in providing a healthy UVR environment by collecting 3-dimensional UVR measurements from eight playgrounds in College Station, Texas, across four seasons. We assessed UVR exposure based on two key metrics: the Minimal Erythema Dose (MED) and the Minimal Vitamin D Dose (MDD). Our findings reveal non-neglectable UVR from the southern sky, particularly during the fall and winter. Trees and a combination of artificial canopies and trees offer more uniform UVR protection compared to other shade structures. During summer, children in College Station face a high risk of excessive UVR exposure, potentially leading to sunburn or skin redness, even under artificial canopies. Conversely, in winter, children may receive insufficient UVR during a 1-h outdoor period, especially under central artificial shades. Based on these observations, we recommend several design solutions to enhance UVR protection, including site-specific UVR evaluations before design, the use of seasonally adjustable shade structures, and strategic planning of children's activities and exposure times according to seasonal and UVR conditions.

Bringing Light into Darkness-Comparison of Different Personal Dosimeters for Assessment of Solar Ultraviolet Exposure

(1) Measuring personal exposure to solar ultraviolet radiation (UVR) poses a major challenges for researchers. Often, the study design determines the measuring devices that can be used, be it the duration of measurements or size restrictions on different body parts. It is therefore of great importance that measuring devices produce comparable results despite technical differences and modes of operation. Particularly when measurement results from different studies dealing with personal UV exposure are to be compared with each other, the need for intercomparability and intercalibration factors between different measurement systems becomes significant. (2) Three commonly used dosimeter types—(polysulphone film (PSF), biological, and electronic dosimeters)—were selected to perform intercalibration measurements. They differ in measurement principle and sensitivity, measurement accuracy, and susceptibility to inaccuracies. The aim was to derive intercalibration factors for these dosimeter types. (3) While a calibration factor between PSF and electronic dosimeters of about 1.3 could be derived for direct irradiation of the dosimeters, this was not the case for larger angles of incidence of solar radiation with increasing fractions of diffuse irradiation. Electronic dosimeters show small standard deviation across all measurements. For biological dosimeters, no intercalibration factor could be found with respect to PSF and electronic dosimeters. In a use case, the relation between steady-state measurements and personal measurements was studied. On average, persons acquired only a small fraction of the ambient radiation.

Estimating personal solar ultraviolet radiation exposure through time spent outdoors, ambient levels and modelling approaches

BACKGROUND

 Evidence on validation of surrogates applied to evaluate the personal exposure levels of solar ultraviolet radiation (UVR) in epidemiological studies is scarce.

OBJECTIVES

 To determine and compare the validity of three approaches, including (i) ambient UVR levels, (ii) time spent outdoors, and (iii) a modelling approach integrating the aforementioned parameters, to estimate personal UVR exposure over a period of six months among indoor and outdoor workers and in different seasons (summer/winter).

METHODS

 This validation study was part of the EU ICEPURE project and was performed between July 2010 and January 2011 in a convenience sample of indoor and outdoor workers in Catalunya - Spain. We developed linear regression models to quantify the variation in the objectively measured personal UVR exposure that could be explained, separately, by the ambient UVR, time spent outdoors, and modelled UVR levels.

RESULTS

Our 39 participants - mostly male and with a median age of 35 years- presented a median daily objectively measured UVR of 0.37 standard erythemal doses (SEDs). The UVR dose was statistically significantly higher in summer and for outdoor workers. The modelled personal UVR exposure and self-reported time spent outdoors could reasonably predict the variation in the objectively measured personal UVR levels (R² = (0.75, 0.79)), whereas ambient UVR was a poor predictor (R² =0.21). No notable differences were found between seasons or occupation.

CONCLUSIONS

 Time outdoors and our modelling approach were reliable predictors and of value to be applied in epidemiological studies of the health effects of current exposure to UVR.