Ultraviolet radiation thin film dosimetry: A review of properties and applications.

Spectroradiometry, radiometry, and dosimetry are employed for the measurement of ultraviolet radiation (UVR) irradiance and non-ionizing exposure. Different types of UVR dosimeter have been developed for measuring personal and environmental UVR exposures since film dosimetry was pioneered in the 1970s. An important type of dosimeter is the thin film variant, which contains materials that undergo changes in optical absorbance when exposed to UVR. These changes can be measured at a specific wavelength using a spectrophotometer. Thin film dosimeters allow UVR exposure measurements on humans at various body sites during daily activities, as well as on plants, animals, and any sites of interest when utilized in a field environment. This review examines the properties and applications of five types of thin film UVR dosimeter that have different dynamic exposure limits and spectral responses. Polysulphone, with a spectral response approximating the human erythema action spectrum, was one of the first materials employed in thin film form for the measurement of UVR exposures up to 1 day, and up to 6 days with an extended dynamic range filter. Polyphenylene oxide has been characterized and employed for personal UVR exposure measurements up to approximately four summer days and has also been used for long-term underwater UVR exposures. Phenothiazine and 8-methoxypsoralen have been reported as suitable for the measurement of longer wavelength UVA exposures. Finally, polyvinyl chloride with an extended dynamic exposure range of over 3 weeks has been shown to have predominantly a spectral response in the UVB and extending up to 340 nm.

Enhanced joint hybrid deep neural network explainable artificial intelligence model for 1-hr ahead solar ultraviolet index prediction.

BACKGROUND AND OBJECTIVE: Exposure to solar ultraviolet (UV) radiation can cause malignant keratinocyte cancer and eye disease. Developing a user-friendly, portable, real-time solar UV alert system especially or wearable electronic mobile devices can help reduce the exposure to UV as a key measure for personal and occupational management of the UV risks. This research aims to design artificial intelligence-inspired early warning tool tailored for short-term forecasting of UV index (UVI) integrating satellite-derived and ground-based predictors for Australian hotspots receiving high UV exposures. The study further improves the trustworthiness of the newly designed tool using an explainable artificial intelligence approach. METHODS: An enhanced joint hybrid explainable deep neural network model (called EJH-X-DNN) is constructed involving two phases of feature selection and hyperparameter tuning using Bayesian optimization. A comprehensive assessment of EJH-X- DNN is conducted with six other competing benchmarked models. The proposed model is explained locally and globally using robust model-agnostic explainable artificial intelligence frameworks such as Local Interpretable Model-Agnostic Explanations (LIME), Shapley additive explanations (SHAP), and permutation feature importance (PFI). RESULTS: The newly proposed model outperformed all benchmarked models for forecasting hourly horizons UVI, with correlation coefficients of 0.900, 0.960, 0.897, and 0.913, respectively, for Darwin, Alice Springs, Townsville, and Emerald hotspots. According to the combined local and global explainable model outcomes, the site-based results indicate that antecedent lagged memory of UVI and solar zenith angle are influential features. Predictions made by EJH-X-DNN model are strongly influenced by factors such as ozone effect, cloud conditions, and precipitation. CONCLUSION: With its superiority and skillful interpretation, the UVI prediction system reaffirms its benefits for providing real-time UV alerts to mitigate risks of skin and eye health complications, reducing healthcare costs and contributing to outdoor exposure policy.

Serial Cross-Sectional Observations of Sun-Protective Behaviors at an Annual Outdoor Motorsport Event in Tropical Queensland, Australia.

Skin cancer, the most prevalent cancer in Caucasians residing at low latitudes, can primarily be prevented by avoiding overexposure to sunlight. Serial cross-sectional observations were conducted at an outdoor motorsport event held in Townsville, Queensland each July (Southern winter) to determine whether sun-protection habits changed over time. Most (71.1%) of the 1337 attendees observed (97.6% lightly pigmented skin, 64.0% male) wore a hat (any style shading the face), while few (18.5%) wore three-quarter or full-length sleeves. While hat-wearing rates (any style) were similar in 2009 (326, 72.6%) and 2013 (625, 70.4%), the use of sun-protective styles (wide-brimmed/bucket/legionnaires) decreased from 29.2% to 18.6% over the same period, primarily because the use of sun-protective hats halved (from 28.7% to 14.0%) among females, while decreasing from 29.4% to 21.1% in males. Although relatively few individuals wore sun-protective (three-quarter-length or full-length) sleeves regardless of year (OR = 0.117, P < 0.0001), encouragingly, the use of sun-protective sleeves more than doubled between 2009 (10.5%) and 2013 (22.5%). Interestingly females, albeit the minority, at this sporting event were less likely to wear a hat (OR = 0.473, P < 0.0001) than males. These findings highlight the need for continued momentum toward skin cancer primary prevention through sun protection with a dedicated focus on outdoor sporting settings.

The Playground Shade Index: A New Design Metric for Measuring Shade and Seasonal Ultraviolet Protection Characteristics of Parks and Playgrounds.

Current shading strategies used to protect outdoor playgrounds from harmful solar radiation include the placement of artificial cloth weaves or permanent roofing over a playground site, planting trees in proximity to playground equipment, and using vegetation or surface texture variations to cool playground surfaces. How and where an artificial shade structure is placed or a tree is planted to maximize the shade protection over specific playground areas, requires careful assessment of local seasonal sun exposure patterns. The Playground Shade Index (PSI) is introduced here as a design metric to enable shade and solar ultraviolet exposure patterns to be derived in an outdoor space using conventional aerial views of suburban park maps. The implementation of the PSI is demonstrated by incorporating a machine learning design tool to classify the position of trees from an aerial image, thus enabling the mapping of seasonal shade and ultraviolet exposure patterns within an existing 7180 m2 parkland. This is achieved by modeling the relative position of the sun with respect to nearby buildings, shade structures, and the identified evergreen and deciduous tree species surrounding an outdoor playground.

A Case Study of UV Exposure Risk in Sydney during the 2019/2020 New South Wales Bushfires.

During summer of 2019/2020, Sydney, Australia, experienced several days of extreme air pollution and low visibility due to bushfires. This research presents a case study that investigates the erythemal UV irradiance and resulting 1 h erythemal and 8 h actinic exposures during the worst of these days. Air quality, meteorological and UV data used in the analysis were readily available online or by request from governmental agencies. Analysis showed that even for the lowest visibility day (which had a minimum visibility of less than a kilometer) on 10 December 2019, there was a cumulative 1 h erythemal UV exposure of over 4 SED (standard erythema dose) and a cumulative 8 h exposure of 17 SED by the late afternoon. The 1 h exposure exceeded that of a minimum erythemal dose. Even on this extremely hazy day, these cumulative exposures are enough to exceed the recommended daily exposure limit for actinic exposures weighted with the health sensitivity spectrum for the skin and eyes set by the International Commission of Non-Ionizing Radiation Protection.

Solar Blue Light Radiation Enhancement during Mid to Low Solar Elevation Periods under Cloud Affected Skies.

Solar blue-violet wavelengths (380-455 nm) are at the high energy end of the visible spectrum; referred to as "high energy visible" (HEV). Both chronic and acute exposure to these wavelengths has been often highlighted as a cause for concern with respect to ocular health. The sun is the source of HEV which reaches the Earth's surface either directly or after scattering by the atmosphere and clouds. This research has investigated the effect of clouds on HEV for low solar elevation (solar zenith angles between 60° and 80°), simulating time periods when the opportunity for ocular exposure in global populations with office jobs is high during the early morning and late afternoon. The enhancement of "bluing" of the sky due to the influence of clouds was found to increase significantly with the amount of cloud. A method is presented for calculating HEV irradiance at sub-tropical latitudes from the more commonly measured global solar radiation (300-3000 nm) for all cases when clouds do and do not obscure the sun. The method; when applied to global solar radiation data correlates well with measured HEV within the solar zenith angle range 60° and 80° (R2 = 0.82; mean bias error (MBE) = -1.62%, mean absolute bias error (MABE) = 10.3% and root mean square error (RMSE) = 14.6%). The technique can be used to develop repeatable HEV hazard evaluations for human ocular health applications.

Biologically effective solar ultraviolet exposures and the potential skin cancer risk for individual gold medalists of the 2020 Tokyo Summer Olympic Games.

Personal solar ultraviolet radiation exposure models were developed for 144 Olympic events scheduled outdoors from across the 33 sport disciplines that will compete in Tokyo between 24 July and 9 August 2020. Ambient exposure models were developed from existing atmospheric parameters measured over Tokyo (35.7°N 139.7°E) and were used to weight erythemally effective solar ultraviolet exposure to gold medalists, taking into account body posture and expected protection by competitor's clothing which was assessed in comparison to respective medalists of the 2016 Rio Olympics. Individual exposure models consider the ultraviolet surface albedo (lawn, concrete, water or sand) and timing of daily events held within Olympic venues. Exposure assessments are presented, including assessments of all preliminary rounds and qualifiers. Within scheduled outdoor events, we award first place (representing the highest and most harmful UV exposure) to the women's tennis singles (1680 J/m2), second to men's golf (1530 J/m2) and third to the men's cycling road race (941 J/m2) for the highest expected erythemally effective solar ultraviolet radiation exposures of the 2020 Tokyo Games. The highest expected solar ultraviolet exposures for nations expected to win greater than three gold medals among the outdoor events were found to occur in athletes from Kenya followed closely by the United States and Hungary. Gold medalists from South Korea were found to demonstrate the highest level of sun protection due to clothing at the 2016 Rio Games, and are thus expected to receive the greatest relative reduction in erythemally effective exposure during the 2020 Tokyo Games.

A review on the ability of smartphones to detect ultraviolet (UV) radiation and their potential to be used in UV research and for public education purposes.

The effects of ultraviolet (UV) radiation on life on Earth have continuously been the subject of research. Over-exposure to UV radiation is harmful, but small amounts of exposure are required for good health. It is, therefore, crucial for humans to optimise their own UV exposure and not exceed UV levels that are sufficient for essential biological functions. Exceeding those levels may increase risk of developing health problems including skin cancer and cataracts. Smartphones have been previously investigated for their ability to detect UV radiation with or without additional devices that monitor personal UV exposure, in order to maintain safe exposure times by individuals. This review presents a comprehensive overview of the current state of smartphones' use in UV radiation monitoring and prediction. There are four main methods for UV radiation detection or prediction involving the use smartphones, depending on the requirements of the user: devoted software applications developed for smartphones to predict UV Index (UVI), wearable and non-wearable devices that can be used with smartphones to provide real-time UVI, and the use of smartphone image sensors to detect UV radiation. The latter method has been a growing area of research over the last decade. Built-in smartphone image sensors have been investigated for UV radiation detection and the quantification of related atmospheric factors (including aerosols, ozone, clouds and volcanic plumes). The overall practicalities, limitations and challenges are reviewed, specifically in regard to public education. The ubiquitous nature of smartphones can provide an interactive tool when considering public education on the effects and individual monitoring of UV radiation exposure, although social and geographic areas with low socio-economic factors could challenge the usefulness of smartphones. Overall, the review shows that smartphones provide multiple opportunities in different forms to educate users on personal health with respect to UV radiation.

Assessment of Biologically Effective Solar Ultraviolet Exposures for Court Staff and Competitors During a Major Australian Tennis Tournament.

Sport is an integral and enduring part of many societies, such as Australia. Participation in outdoor sports, such as tennis, comes with a very real risk of dangerous solar ultraviolet exposure which can result in erythema (sunburn), serious conditions such as skin cancer, including melanoma, and eye conditions such as cataracts and pterygium. This study remotely assesses the effective ultraviolet exposures in response to the increased sun safety awareness at a major summertime tennis tournament in Australia. The assessment only uses publicly accessible data and information. It was found that tournament organizers have effectively adopted sun-safe protocols into the uniform policy that the court officials (judges and ball kids) are mandated to follow. The combination of sun-participant geometry and the photoprotection provided by uniforms significantly reduced the ambient ultraviolet exposure, which was recorded to be as high as 9.9 SED h-1 , to just 1.0 and 0.5 SED h-1 for ball kids and judges, respectively, compared to up to 2.0 SED h-1 for players. Even though caution is needed against complacency with sun safety, with the need for the court officials and the players to still apply sunscreen, the court officials provided persistent visual role modeling of sun-safe behaviors.

Seasonal Minimum and Maximum Solar Ultraviolet Exposure Measurements of Classroom Teachers Residing in Tropical North Queensland, Australia.

The risk of keratinocyte skin cancer, malignant melanoma and ultraviolet radiation (UVR)-induced eye disease is disproportionately higher in Australia and New Zealand compared to equivalent northern hemisphere latitudes. While many teachers are aware of the importance of reinforcing sun safety messages to students, many may not be aware of the considerable personal exposure risk while performing outdoor duties in locations experiencing high to extreme ambient UVR year-round. Personal erythemally effective exposure of classroom teachers in tropical Townsville (19.3°S) was measured to establish seasonal extremes in exposure behavior. Mean daily personal exposure was higher in winter (91.2 J m-2 , 0.91 Standard Erythema Dose [SED]) than summer (63.3 J m-2 , 0.63 SED). The range of exposures represents personal exposures that approximate current national guidelines for Australian workers at the study latitude of approximately 1.2 SED (30 J m-2 effective to the International Commission on Non-Ionizing Radiation Protection). Similar proportions of teachers spent more than 1 h outdoors per day in winter (28.6%) and summer (23.6%) as part of their teaching duties with seasonal differences having little effect on the time of exposure. Personal exposures for teachers peaked during both seasons near school meal break times at 11:00 am and 1:00 pm, respectively.

A Pilot Observational Study of Environmental Summertime Health Risk Behavior in Central Brisbane, Queensland: Opportunities to Raise Sun Protection Awareness in Australia's Sunshine State.

Melanoma skin cancer rates in Queensland exceed the national Australian incidence rate, which together with New Zealand are recognized as the world's highest. Incidence is especially high among younger members of the population. In this study, the sun-protective behaviors of urban Queenslanders (n = 752) going about their day-to-day activities during a midweek noon time hourly period were observed on a summer's day in central Brisbane (27.47°S, 153.03°E), Australia. Observed sun protection practices were poor, given the time of year and peak solar noon period of the study. More individuals (n = 249; 33.1%) were seen wearing sunglasses than a hat (n = 101; 13.4%). Ninety-three individuals were actively engaging with mobile phones (phone in hand). A further 231 individuals (30.7%) were observed with a mobile phone on them. Opportunities to modify group behavior based on mobile phone sun protection notifications and to engage with "at risk" members of the Queensland population are considered from the variable codependencies examined in this study, including the influence of social group size, observed sun protection and mobile phone use. Our preliminary findings suggest that mobile phones provide an underutilized opportunity for delivering tailored skin cancer prevention messaging.

Ultraviolet Radiation Albedo and Reflectance in Review: The Influence to Ultraviolet Exposure in Occupational Settings.

Ultraviolet (UV) albedo and UV reflectance are defined, compared and contrasted, to explain their roles and place in studies focusing on UV radiation and exposure measurements, in the context of localised albedo measurement and human UV exposure studies. This review recommends that the term UV albedo be used when investigating natural horizontal surfaces when the albedo is not known to change significantly over time. The term UV reflectance should be mostly used for non-natural surfaces and non-horizontal measurements and will change with respect to the geometry of the irradiances reflected and received, and due to the intrinsic nature of the surface itself. UV albedo measurements made in the literature have been compiled, in both broadband and spectral UV albedo measurements. Broadband measurements have been tabulated and spectral UV measurements have been displayed visually. The methodology of measurements is briefly discussed. Finally, studies that consider how high albedo or reflectance sites influence UV exposure are reviewed. It was concluded that there is currently no known relationship between the albedo or reflectance of a surface and the resulting influence it has on individual UV exposure. This presents an opportunity for researchers to continue exploring the influence of reflective UV surfaces.

The geospatial relationship of pterygium and senile cataract with ambient solar ultraviolet in tropical Ecuador.

Tropical Ecuador presents a unique climate in which we study the relationship between the ambient levels of solar ultraviolet radiation and eye disease in the absence of a latitudinal gradient. The national distribution of surface ultraviolet, taking into account MODIS and OMI satellite observation of aerosol, ozone, surface albedo, local elevation and cloud fractions measured during 2011, was compared with the national pterygium (WHO ICD H11) and senile cataract (WHO ICD H25) incidence projected from the 2010 National Institute of Statistics and Census (Ecuador). Public Health Ministry projections for age categories 0 to 39, 40 to 59 and 60+ years were compared to surface ultraviolet irradiance data in 1040 parishes. Correlations drawn between modelled surface ultraviolet and eye disease incidence show a significant increase in both pterygium and senile cataract in the highest ambient exposure regions of the Pacific coast and western lowlands with incidence rates of 34.39 and 16.17 per 100 000 residents respectively. The lowest rates of incidence for pterygium (6.89 per 100 000) and senile cataract (2.90 per 100 000) were determined in high altitude sites and are attributed here to increased daily cloud fraction for parishes located in the Andean mountain range. The South American Andes experience the highest solar UV exposures on Earth and report frequent high incidence of keratinocyte cancer. Our results show the high Andes to be the location of the lowest eye disease incidence suggesting that both pterygium and senile cataract are the result of cumulative exposure to solar ultraviolet. These findings have clear implications for the agricultural workers and fishermen of the lowland districts of Ecuador, contrary to conventional understanding that greater risks are faced in locations of high altitude.

An Inexpensive High-Temporal Resolution Electronic Sun Journal for Monitoring Personal Day to Day Sun Exposure Patterns.

Exposure to natural sunlight, specifically solar ultraviolet (UV) radiation contributes to lifetime risks of skin cancer, eye disease, and diseases associated with vitamin D insufficiency. Improved knowledge of personal sun exposure patterns can inform public health policy; and help target high-risk population groups. Subsequently, an extensive number of studies have been conducted to measure personal solar UV exposure in a variety of settings. Many of these studies, however, use digital or paper-based journals (self-reported volunteer recall), or employ cost prohibitive electronic UV dosimeters (that limit the size of sample populations), to estimate periods of exposure. A cost effective personal electronic sun journal (ESJ) built from readily available infrared photodiodes is presented in this research. The ESJ can be used to complement traditional UV dosimeters that measure total biologically effective exposure by providing a time-stamped sun exposure record. The ESJ can be easily attached to clothing and data logged to personal devices (including fitness monitors or smartphones). The ESJ improves upon self-reported exposure recording and is a cost effective high-temporal resolution option for monitoring personal sun exposure behavior in large population studies.

Very short-term reactive forecasting of the solar ultraviolet index using an extreme learning machine integrated with the solar zenith angle.

Exposure to erythemally-effective solar ultraviolet radiation (UVR) that contributes to malignant keratinocyte cancers and associated health-risk is best mitigated through innovative decision-support systems, with global solar UV index (UVI) forecast necessary to inform real-time sun-protection behaviour recommendations. It follows that the UVI forecasting models are useful tools for such decision-making. In this study, a model for computationally-efficient data-driven forecasting of diffuse and global very short-term reactive (VSTR) (10-min lead-time) UVI, enhanced by drawing on the solar zenith angle (θs) data, was developed using an extreme learning machine (ELM) algorithm. An ELM algorithm typically serves to address complex and ill-defined forecasting problems. UV spectroradiometer situated in Toowoomba, Australia measured daily cycles (0500-1700h) of UVI over the austral summer period. After trialling activations functions based on sine, hard limit, logarithmic and tangent sigmoid and triangular and radial basis networks for best results, an optimal ELM architecture utilising logarithmic sigmoid equation in hidden layer, with lagged combinations of θs as the predictor data was developed. ELM's performance was evaluated using statistical metrics: correlation coefficient (r), Willmott's Index (WI), Nash-Sutcliffe efficiency coefficient (ENS), root mean square error (RMSE), and mean absolute error (MAE) between observed and forecasted UVI. Using these metrics, the ELM model's performance was compared to that of existing methods: multivariate adaptive regression spline (MARS), M5 Model Tree, and a semi-empirical (Pro6UV) clear sky model. Based on RMSE and MAE values, the ELM model (0.255, 0.346, respectively) outperformed the MARS (0.310, 0.438) and M5 Model Tree (0.346, 0.466) models. Concurring with these metrics, the Willmott's Index for the ELM, MARS and M5 Model Tree models were 0.966, 0.942 and 0.934, respectively. About 57% of the ELM model's absolute errors were small in magnitude (±0.25), whereas the MARS and M5 Model Tree models generated 53% and 48% of such errors, respectively, indicating the latter models' errors to be distributed in larger magnitude error range. In terms of peak global UVI forecasting, with half the level of error, the ELM model outperformed MARS and M5 Model Tree. A comparison of the magnitude of hourly-cumulated errors of 10-min lead time forecasts for diffuse and global UVI highlighted ELM model's greater accuracy compared to MARS, M5 Model Tree or Pro6UV models. This confirmed the versatility of an ELM model drawing on θsdata for VSTR forecasting of UVI at near real-time horizon. When applied to the goal of enhancing expert systems, ELM-based accurate forecasts capable of reacting quickly to measured conditions can enhance real-time exposure advice for the public, mitigating the potential for solar UV-exposure-related disease.

Solar ultraviolet and the occupational radiant exposure of Queensland school teachers: A comparative study between teaching classifications and behavior patterns.

Classroom teachers located in Queensland, Australia are exposed to high levels of ambient solar ultraviolet as part of the occupational requirement to provide supervision of children during lunch and break times. We investigated the relationship between periods of outdoor occupational radiant exposure and available ambient solar radiation across different teaching classifications and schools relative to the daily occupational solar ultraviolet radiation (HICNIRP) protection standard of 30J/m(2). Self-reported daily sun exposure habits (n=480) and personal radiant exposures were monitored using calibrated polysulphone dosimeters (n=474) in 57 teaching staff from 6 different schools located in tropical north and southern Queensland. Daily radiant exposure patterns among teaching groups were compared to the ambient UV-Index. Personal sun exposures were stratified among teaching classifications, school location, school ownership (government vs non-government), and type (primary vs secondary). Median daily radiant exposures were 15J/m(2) and 5J/m(2)HICNIRP for schools located in northern and southern Queensland respectively. Of the 474 analyzed dosimeter-days, 23.0% were found to exceed the solar radiation protection standard, with the highest prevalence found among physical education teachers (57.4% dosimeter-days), followed by teacher aides (22.6% dosimeter-days) and classroom teachers (18.1% dosimeter-days). In Queensland, peak outdoor exposure times of teaching staff correspond with periods of extreme UV-Index. The daily occupational HICNIRP radiant exposure standard was exceeded in all schools and in all teaching classifications.

Minimum exposure limits and measured relationships between the vitamin D, erythema and international commission on non-ionizing radiation protection solar ultraviolet.

The International Commission on Non-Ionizing Radiation Protection (ICNIRP) has established guidelines for exposure to ultraviolet radiation in outdoor occupational settings. Spectrally weighted ICNIRP ultraviolet exposures received by the skin or eye in an 8 h period are limited to 30 J m(-2). In this study, the time required to reach the ICNIRP exposure limit was measured daily in 10 min intervals upon a horizontal plane at a subtropical Australian latitude over a full year and compared with the effective Vitamin D dose received to one-quarter of the available skin surface area for all six Fitzpatrick skin types. The comparison of measured solar ultraviolet exposures for the full range of sky conditions in the 2009 measurement period, including a major September continental dust event, show a clear relationship between the weighted ICNIRP and the effective vitamin D dose. Our results show that the horizontal plane ICNIRP ultraviolet exposure may be used under these conditions to provide minimum guidelines for the healthy moderation of vitamin D, scalable to each of the six Fitzpatrick skin types.

Shade provision for UV minimization: a review.

Minimizing exposure to ultraviolet (UV) radiation is an essential component of skin cancer prevention. Providing and using natural and built shade is an effective protection measure against harmful UV. This article describes the factors that must be addressed to ensure quality, effective, well-designed shade and recommends best practice approaches to improving the protection factor (PF) of shade structures. It identifies examples of interventions to increase shade availability and use, and examples of effective shade based on measured protection factors or measured reductions in UV exposures. Finally, this article considers examples of best practice for undertaking shade audits. The article is based on refereed articles and reviews, reports, conference papers and shade practice and policies from reports and on web sites. Articles for the Australian setting are considered first, followed by those in an international setting.

Optical properties of a long dynamic range chemical UV dosimeter based on solvent cast polyvinyl chloride (PVC).

The dosimetric properties of the recently introduced UV dosimeter based on 16 µm PVC film have been fully characterised. Drying the thin film in air at 50 °C for at least 28 days was found to be necessary to minimise the temperature effects on the dosimeter response. This research has found that the dosimeter response, previously reported to be mainly to UVB, has no significant dependence on either exposure temperature or dose rate. The dosimeter has negligible dark reaction and responds to the UV radiation with high reproducibility. The dosimeter angular response was found to have a similar pattern as the cosine function but deviates considerably at angles larger than 70°. Dose response curves exhibit monotonically increasing shape and the dosimeter can measure more than 900 SED. This is about 3 weeks of continuous exposure during summer at subtropical sites. Exposures measured by the PVC dosimeter for some anatomical sites exposed to solar radiation for twelve consecutive days were comparable with those concurrently measured by a series of PPO dosimeters and were in line with earlier results reported in similar studies.

Influence of reflected UV irradiance on occupational exposure from combinations of reflective wall surfaces.

Outdoor workers who occupationally spend large periods of time exposed to ultraviolet irradiance are at increased risk of developing certain types of non-melanoma skin cancer in addition to being prone to erythema and eye damage. UV exposure to workers is affected by a number of factors including geographic location, season, individual biological factors and the local surroundings. Urban environments can provide surrounds that contain surfaces that reflect UV radiation which can enhance UV exposure to construction workers, in both the vertical as well as horizontal plane. However it was unknown how different constructed configurations of the surfaces may additionally influence UV exposure for a worker, such as corners opposed to walls. This study shows that for highly UV reflective surfaces the influence on erythemal UV exposure is approximately the same regardless of constructive type, but there is statistically significant difference observed for lower UV reflecting surfaces in conjunction with constructive type. This is comparable to influence of body site on relative UV exposure, and together may provide a method that may assist in reduction in UV exposures. Regression analysis provides a more effective means to determine a UV reflective factor for a surface type, than previously used averaging methods. Additionally, this knowledge may be used by workers, workplaces and advisory bodies to assist with developing further protective strategies that aim to provide more moderate UV exposures to outdoor workers.