Nathan James Downs

University of Southern Queensland · Faculty of Health, Engineering and Sciences

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 fil...

Shade audits implemented for the assessment of solar ultraviolet (UV) protection within parks and playgrounds require standardisation in order to make clear and objective comparisons of the whole environment. Children utilising a park or playground may use a recreational space only at a certain time of day, they may only utilise a specific area of...

Standardised tree shade assessments yield important information on canopy density, size and solar protection within the urban environment. Designing for shade by trees that are to be planted along narrow suburban nature strips, parks and playgrounds requires a detailed understanding of both the constraints and benefits based on location. Safety and...

Sea level rise (SLR) attributed to the melting of ice caps and thermal expansion of seawater is of great global significance to vast populations of people residing along the world’s coastlines. The extent of SLR’s impact on physical coastal areas is determined by multiple factors such as geographical location, coastal structure, wetland vegetation...

Tree shade, particularly shade that obscures direct sunlight near peak periods of midday solar exposure can have a pronounced effect on potentially harmful ultraviolet radiation, and in turn, strongly influence the maximum daily UV index (UVI). In this study, the seasonal influence of tree shade on the UVI is evaluated from 210 hemispherical sky vi...

Fluctuations in direct sunlight intensities (or sunflecks) are experienced in urban forest parklands. A novel application of an electronic sun journal (ESJ) was developed providing accessible, objective detection and analysis of sunflecks sampled at 50 Hz while walking through urban parkland forests in Toowoomba (27.57°S 151.95°E), Australia. A tot...

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...

High-dose single exposures of long-wavelength ultraviolet-A (UV-A) radiation may trigger severe biological and skin tissue damage in humans and animals, as well as photosynthetic damage in plants. In humans, the highly abundant UV-A is also linked to an increased risk of skin cancer. This paper develops a new forecasting framework tailored for very...

The Playground Shade Index (PSI) is introduced as a design metric for assessing the shade and solar ultraviolet (UV) protection provided by eight different cloth weave shade structures currently utilized in public playgrounds across a regional city located in southern Queensland, Australia. The PSI, expressing the ratio of available ambient solar U...

The impact of ultraviolet (UV) radiation on public health is severe and can cause sunburn, skin aging and cancer, immunosuppression, and eye damage. Minimization of exposure to solar UV is required in order to reduce the risks of these illnesses to the public. Greater public awareness and a prediction of the ultraviolet index (UVI) is considered an...

Skin cancer, the most prevalent cancer in Caucasians residing at low latitudes, can primarily be prevented by avoiding over‐exposure 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. M...

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 sha...

Introductory Engineering Mathematics (a skill builder for engineers) involves developing problem-solving attributes throughout the teaching period. Therefore, the prediction of students’ final course grades with continuous assessment marks is a useful toolkit for degree program educators. Predictive models are practical tools used to evaluate the e...

Forecast models of solar radiation incorporating cloud effects are useful tools to evaluate the impact of stochastic behaviour of cloud movement, real-time integration of photovoltaic energy in power grids, skin cancer and eye disease risk minimisation through solar ultraviolet (UV) index prediction and bio-photosynthetic processes through the mode...

Harmful exposure to erythemally-effective ultraviolet radiation (UVR) poses high health risks such as malignant keratinocyte cancers and eye-related diseases. Delivering short-term forecasts of the solar ultraviolet index (UVI) is an effective way to advise UVR exposure information to the public at risk. This research reports on a novel framework b...

During summer 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 one-hour erythemal and 8-hour actinic exposures during the worst of these days. Air quality, meteorological and UV data use...

Forecast models of solar radiation incorporating cloud effects are useful tools to evaluate the impact of stochastic behaviour of cloud movement, real-time integration of photovoltaic energy in power grids, skin cancer and eye disease risk minimisation through solar ultraviolet (UV) index prediction and bio-photosynthetic processes through the mode...

Skin cancers are strongly linked to personal exposure to ultraviolet (UV) radiation, yet UV exposure is also the most preventable risk factor. People are exposed to UV rays when they engage in outdoor activities, particularly exercise, which is an important health behavior. Thus, researchers and the general public have shown increasing interest in...

bold xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Skin cancers are one of the most common types of cancer in the United States [1] , and melanoma has steadily increased over the last 20 years. Solar ultraviolet radiation (UVR) is known as the main cause of damaging effects to the skin [1] , [2] ,...

Excessive exposure to solar ultraviolet (UV) radiation has damaging effects on life on Earth. High-energy short-wavelength ultraviolet B (UVB) is biologically effective, influencing a range of dermal processes, including the potentially beneficial production of vitamin D. In addition to the damaging effects of UVB, the longer wavelength and more ab...

This research compared personal sunlight exposure times monitored electronically within suburban Australian environments against self-report paper journals for determining the timing and total duration of individual exposure to daily solar radiation. A total of 90 Electronic Sun Journal (ESJ) daily readings and self-report timing and duration estim...

Relative keratinocyte skin cancer risks attributable to lifetime occupational and casual sunlight exposures of working school teachers are assessed across the state of Queensland for 1578 schools. Relative risk modeling utilizing annual ultraviolet exposure assessments of teachers working in different geographic locations and exposed during periods...

This research presents a novel methodology for deriving the total daily broadband solar UVA (320-400 nm) received by school teachers during their working day from Ozone Monitoring Instrument (OMI) satellite solar noon UVA irradiance measurements for a Queensland sub-tropical site (27.5o S, 152o E). Daily UVA exposures are weighted to the anatomical...

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 directl...

Precise shade distributions at the street level are an area of research of increasing importance to provide complete and high spatial and temporal resolutions of the amount and effectiveness of shade. Temporal shade distributions and profiles were evaluated for an inner Sydney tree-lined suburban street at different times of the day using an electr...

Triathletes present an extreme case of modelled behaviour in outdoor sport that favours enhanced exposure to solar ultraviolet radiation. This research presents personal solar ultraviolet exposures, measured using all-weather polysulphone film dosimeters, to triathletes during the distinct swimming, cycling and running stages of competitive Sprint,...

Kiteboarding is an aquatic sporting discipline that has not yet been considered in the literature to date in terms of solar ultraviolet radiation (UVR) measurement. Kiteboarders need to look upward and are placed obliquely relative to the horizon when towed behind an overhead kite over a reflective water surface. This research defines the typical b...

The presentation provides a summary of recent research into dynamic auditing techniques used to assess tree shade and shade provided by purpose built structures. Preliminary results for a recent shade audit conducted in the South Bank Parklands, Brisbane are also presented.

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 cons...

This research investigated and evaluated the influence of clouds on the total daily UVA (320–400 nm) exposures calculated from the three Ozone Monitoring Instrument (OMI) UV spectral irradiances at solar noon. These evaluated satellite total daily UVA exposure data were compared to the total daily UVA exposures of a ground-based instrument over the...

A standardised procedure for making fair and comparable assessments of the ultraviolet protection of an established tree canopy that takes into account canopy movement and the changing position of the sun is presented for use by government, planning, and environmental health authorities. The technique utilises video image capture and replaces the n...

Standardised assessments comparing the surveyed shade quality characteristics of twenty-one trees currently established and growing in public parks and playgrounds in Queensland, Australia are presented for informing local government, shade designers and municipal planners. Assessments focus on the ultraviolet protection of individual tree canopies...

New and improved drought models based on the World Meteorological Organization approved Standardized Precipitation Index, principally at multiple timescale horizons, are providing significant benefits to the hydrological community, by its widespread acceptance in the sub-field of water resources management, sustainable water use and precision agric...

Acquiring the reflectance, radiance, and related structural cloud properties from repositories of historical sky images is a challenging and a computationally intensive task, especially when performed manually or by means of nonautomated approaches. In this article, a quick and efficient, self-adaptive Python tool for the acquisition, and analysis...

To support alternative forms of energy resources, the prediction of global incident solar radiation (Irad) is critical to establish the efficacy of solar energy resources as a free and clean energy, and to identify and screen solar powered sites. Solar radiation data for construction of energy feasibility studies are not available in many locations...

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 eryt...

A method was proposed for calculating the ultraviolet protection factor (PF) of small to medium built shade structures. The method takes into account the amount of sky view visible from under the structure, the transmittance of the roof material, the relative amount of diffuse ultraviolet radiation (UV), the measurement position under the structure...

Reliable data-driven models designed to accurately estimate cotton yield, an important agricultural commodity, can be adopted by farmers, agricultural system modelling experts and agricultural policy-makers in strategic decision-making processes. In this paper a hybrid genetic programing model integrated with the Markov Chain Monte Carlo (MCMC) bas...

Advocacy for climate mitigation aims to minimize the use of fossil fuel and to support clean energy adaptation. While alternative energies (e.g., biofuels) extracted from feedstock (e.g., micro‐algae) represent a promising role, their production requires reliably modeled photosynthetically active radiation (PAR). PAR models predict energy parameter...

The presentation summarises recent progress in developing an electronic sun journal to document personal exposure time in the sun. Personal exposure time is compared with calibrated field radiometers which measure the ambient UV irradiance. Exposure timing is compared to ambient measurements to derive personal UV exposure from published exposure ra...

Melanoma skin cancer rates in Queensland exceed the national Australian incidence rate, which together with New Zealand are recognised as the world's highest. Incidence is especially high among younger members of the population. In this study, the sun‐protective behaviours of urban Queenslanders (n = 752) going about their day‐to‐day activities dur...

Drought forewarning is an important decisive task since drought is perceived a recurrent feature of climate variability and climate change leading to catastrophic consequences for agriculture, ecosystem sustainability, and food and water scarcity. This study designs and evaluates a soft-computing drought modelling framework in context of Pakistan,...

To ameliorate agricultural impacts due to persistent drought-risks by promoting sustainable utilization and pre-planning of water resources, accurate rainfall forecasting models, addressing the dynamic nature of drought phenomenon, is crucial. In this paper, a multi-stage probabilistic machine learning model is designed and evaluated for forecastin...

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Tropical Ecuador presents a unique climate in which to study the relationship between 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...

This research investigated the influence of cloud on the broadband UVA solar noon irradiances evaluated from the solar noon satellite based OMI spectral UV data that were compared to the irradiances of a ground‐based radiometer from 1 October 2004 to 31 December 2016. The correlation between ground‐based radiometer data and the evaluated OMI broadb...

The precise prediction of windspeed is essential in order to improve and optimize wind power prediction. However, due to the sporadic and inherent complexity of weather parameters, the prediction of windspeed data using different patterns is difficult. Machine learning (ML) is a powerful tool to deal with uncertainty and has been widely discussed a...

Designing predictive models of global solar radiation can be an effective renewable energy feasibility studies approach to resolve future problems associated with the supply, reliability and dynamical stability of consumable energy demands generated by solar-powered electrical plants. In this paper we design and present a new approach to predict th...

Introduction: The populated regions of the high tropical Andes experience near zenith daily solar elevations year-round and are often located several thousand metres above sea level. Consequently, the tropical Andes are a global hot spot for potential solar induced diseases. The 2010 National Institute of Statistics and Census (INEC, Ecuador) repor...

Introduction: Clothing provides a protective barrier that reduces the amount of ultraviolet radiation (UVR) reaching the skin. Industry standards for sun-protective clothing have been implemented in Australia/New Zealand, Europe, and the USA. However, ratings and labelling used for clothing marketed as sun-protective do not routinely communicate th...

Introduction: To date, no cumulative evidence has been collected on the solar ultraviolet exposure received by triathlon competitors assessing the cumulative and discrete exposure risks measured during the swim, bicycle and running legs of competitive Australian Ironman events. This sport has previously been highlighted as having potential for very...

Smartphone applications that predict UV radiation exposure are evolving in ways to assist the user in determining how much protection from exposure to UV radiation should or might occur. The usefulness of these apps are apparent, yet many do not harness the entire range of capabilities of a smartphone. Research performed at the University of Southe...

The signal to noise ratio (SNR) is an important consideration for any scientific image sensor application, particularly the relatively low light involved with observations of the solar disc at a discrete ultraviolet-B (UVB) wavelength using an unmodified smartphone image sensor. In particular, the SNR of each of the primary image sensor colour chan...

Excessive exposure to sunlight causes skin cancer, the most common cancer in humans. An estimated 80% of melanoma (the most deadly form of skin cancer) cases in Australia could be prevented by reducing sun exposure. Clothing provides a protective barrier that reduces the amount of solar ultraviolet radiation (UVR) reaching the skin. In 1996, Austra...

过度暴露于阳光中会导致皮肤癌,这是人类最常见的癌症。在澳大利亚,约有80%的黑色素瘤(皮肤癌最致命的形式)病例可以通过减少阳光曝晒进行预防。衣服可以作为防护屏障,有效地减少到达皮肤的太阳紫外辐射(UVR)。1996年,澳大利亚的研究人员根据UVR穿透衣料的情况(称为紫外线防护系数(UPF))主导了一项衣服的防晒能力相对等级研究。UPF服装吊牌作为此项初始标准(AS/NZS 4399:1996)的一部分引入,这一做法被业界广泛采用。然而,这项研究并未考虑到服装覆盖的人体皮肤表面积(BSA)。一些标准(例如欧盟,2003年;澳大利亚/新西兰,2017年)中加入了对躯体和四肢的最低身体覆盖面积要求,而其他标准(例如美国)则未有改动。鉴于有最新证据表明,衣服覆盖对预防在幼年时期形成的色素痣(黑色素瘤...

Forecasting drought by means of the World Meteorological Organization-approved Standardized Precipitation Index (SPI) is considered to be a fundamental task to support socio-economic initiatives and effectively mitigating the climate-risk. This study aims to develop a robust drought modelling strategy to forecast multi-scalar SPI in drought-rich re...

A new method for quantifying the total ozone column (TOC) using a smartphone image sensor has been developed and validated. The TOC has been evaluated for relatively cloud free days at high air masses for solar zenith angles between 49.7° and 76.7° at a sub-tropical site. The method is based on the evaluation of the direct solar irradiances at 305...

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 num...

Background: National standards for clothing designed to protect the wearer from the harmful effects of solar ultraviolet radiation (UVR) have been implemented in Australia/New Zealand, Europe, and the USA. Industry standards reflect the need to protect the skin by covering a considerable proportion of the potentially exposed body surface area (BSA...

This research reconstructed and validated the broadband UVA irradiances derived from discrete spectral irradiance data retrieved from the Ozone Monitoring Instrument (OMI) satellite from 1 January to 31 December 2009. OMI data at solar noon was compared to ground based spectral irradiances at Toowoomba (27°36' S 151°55' E), Australia at 310, 324 an...

Personal exposure to solar ultraviolet radiation (UVR) is acknowledged as having both positive and negative effects on human health. This study aimed to measure concurrently the personal erythemal UV, UVA and vitamin D effective exposures of participants in each season of a year. Participants were all indoor office workers located at two different...

The ultraviolet A (UVA) (315-400 nm) daily exposures and maximum daily irradiances from the Global Ozone Monitoring Experiment (GOME)-2 satellite have been compared over three years to the corresponding data from a groundbased spectroradiometer for a subtropical Southern Hemisphere site. This is one of the first such comparisons for the GOME-2 UVA...

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 for...

A set of online activities for children and the community that are based on an integrated real-time solar UV and cloud measurement system are described. These activities use the functionality of the internet to provide an educative tool for school children and the public on the influence of cloud and the angle of the sun above the horizon on the gl...

Thin film dosimeters have been used for the measurement of solar radiation since the 1970s. Their application includes personal exposure measurement and environmental exposure monitoring. Polyphenylene oxide (PPO) films have recently been developed for use in various underwater environments. These dosimeters are capable of measuring solar ultraviol...

The large dust event of 23 September 2009 is recognized as the most significant on record in Australia since the 1940s. At its peak, reported hourly average particulate concentrations exceeded 15 000 µ gm−3, significantly exceeding the Australian National Air Quality Standard of 50 µ gm−3 and daily September averages of 20 – 25 µ gm−3. Measurements...

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 di...

A miniaturized ultraviolet radiation (UV) dosimeter based on polyphenylene oxide (PPO) has been dual calibrated for both erythemal and vitamin D effective exposures (UVB 280 – 320 nm) over extended periods up to five days. Optimal human health requires a balanced amount of UVB exposure as both too much and too little have different but serious pote...

A smartphone sky camera and associated image analysis algorithm has been developed and validated to determine total cloud cover and the percentage of thick and thin clouds using supervised image classification for a range of cloud types, cloud cover from 4% to 98%, and solar zenith angles between 6° and 49°. Additionally, this system provides the p...

A short series of practical classroom mathematics activities employing the use of a large and publicly accessible scientific data set are presented for use by students in years 9 and 10. The activities introduce and build understanding of integral calculus and trigonometric functions through the presentation of practical problem solving that focuse...

Introduction: Personal exposure to solar Ultraviolet radiation (UVR) is a significant risk factor for the development of both cutaneous melanoma (CM) and non-­‐melanocytic skin cancers (NMSC). UVR dosimeter studies have been invaluable in establishing occupational exposure guidelines for relevant industries, and of considerable interest to relevant...

Clothing provides a protective barrier that reduces the amount of ultraviolet radiation (UVR) reaching the skin. Although swim-shirts have grown in popularity in Australia particularly among children, clothing remains under-utilized as a form of sun-protection in contemporary society. Australia pioneered the relative ranking describing the sun-prot...

Sunlight is a known skin carcinogen. Skin cancer is the most common form of cancer in humans, and typically affects sun-exposed parts of the body. Clothing provides a protective barrier that reduces the amount of ultraviolet radiation (UVR) reaching the skin. Australia pioneered the development of a relative ranking of the sun-protective capabiliti...

Background/Aims: Occupational exposure guidelines have been developed by the International Commission on Non-Ionizing Radiation Protection (ICNIRP) which weight a UV source corresponding to its potential to cause harm to the skin or eye. When weighted across the incident UV spectrum this limit is expressed as 30 Jm-2 per 8 hour working day. Local c...

Sunlight is a known skin carcinogen. Skin cancer is the most common form of cancer in humans, and typically affects sun-exposed parts of the body. Sunny Australia and New Zealand have the highest incidence of skin cancer globally. Clothing provides a protective barrier that reduces the amount of ultraviolet radiation (UVR) reaching the skin. Austra...

Sunlight is a known skin carcinogen. Skin cancer is the most common form of cancer in humans, and typically affects sun-exposed parts of the body. Sunny Australia and New Zealand have the highest incidence of skin cancer globally. Clothing provides a protective barrier that reduces the amount of ultraviolet radiation (UVR) reaching the skin. Austra...

A miniaturized UVA dosimeter based on 8-methoxypsoralen (8-MOP) has been developed and characterized for the evaluation of UVA (320-400nm) exposures over extended periods longer than one day. Current research indicates that UVA is a contributing factor in non-melanoma skin cancers and the associated financial cost of damage caused by UVA is signifi...

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 hr period are limited to 30 Jm−2. In this study, the time required to reach the ICNIRP expo...

Engaging students and the public in understanding UV radiation and its effects is achievable using the real time experiment that incorporates blueprint paper, an “educational toy” that is a safe and easy demonstration of the cyanotype chemical process. The cyanotype process works through the presence of UV radiation. The blueprint paper was investi...

The influence of cloud on the solar UVA (320-400nm) exposures over five minute periods on a horizontal plane has been investigated. The first approach used cloud modification factors that were evaluated using the influence of clouds on the global solar exposures (310-2800nm) and a model developed to apply these to the clear sky UVA exposures to all...

Simultaneous personal measurements of the occupational ultraviolet exposure weighted to the International Commission on Non-Ionising Radiation Protection hazard sensitivity spectrum (UVICNIRP) were made over a five week period (44 person-days) in the second half of the summer school term of 2012 in Queensland, Australia for individual high school t...

One of the key issues today with carrying across the message of the effects of ultraviolet radiation and its impact on people today, is providing a simple and effective means that is easy to understand for the younger generation and in turn the general public. There is a simple and easy to present experiment to explain this effect. The product is e...