Clothing Protection from Ultraviolet Radiation: A New Method for Assessment

Comprehensive assessment for hygrothermal comfort with heat and mass fluxes through a clothing layer during cooling seasons

A comprehensive analysis is carried out for achieving hygrothermal comfort by using bidirectional heat and mass fluxes between the human skin and its surroundings during cooling seasons, considering the main characteristics of climate, metabolic rate, and clothing fabrics. As hygrothermal comfort is mainly seen as one-direction heat and mass flux from the close surroundings to the human body, without the emitted heat and mass by the human skin, the purpose of the analysis is to find out proper features of the respective clothing fabric according to the inlet boundary conditions, i.e. heat and mass flux from the human body, and the outlet boundary features, i.e. heat and mass flux due to the climate conditions. Thereby, a novel mathematical modelling is developed for heat and mass transfer, respectively. Then, the software Wolfram Mathematica is applied for the numerical solutions of the model. After the model is validated, a sensitivity analysis is carried out. Thereby, it is found that the sensible heat removal by convection, dependent on both airflow and humidity rates, has a great influence on the hygrothermal comfort. Furthermore, solar reflectivity for shortwave radiation, along with longwave radiation from the skin, have influence on the hygrothermal comfort when both ventilation and sweating are set as minimum. Therefore, if the conditions of temperature and relative humidity are proper, both high conductivity and air permeability clothes are recommended. Nevertheless, regarding the reflectivity, it depends on the presence of shortwave radiation, sweating, ventilation, and longwave radiation to consider light-toned or dark colors.

Exposed Body Surface Area-A Determinate for UV Radiant Energy in Human UV Exposure Studies

Solar ultraviolet (UV) exposure of people and related health risk is mainly examined by estimating the received UV radiant exposure. However, for several effects such as DNA damage, vitamin D photosynthesis or the probability of developing skin cancer, UV radiant energy is important and with that the size of exposed skin area. There is also a complex interaction between body shape and behavior like sun exposure habits, so that careful analysis is necessary when estimating health effects from UV exposure. In this paper, knowledge on body shape and methods of calculating the total body surface area (BSA) are summarized. BSA depends mainly on the height and weight of a person as well as on gender, ethnicity and body shape. BSA and body shape differ significantly between different populations and both change during life. This paper proposes formulas for BSA that consider height, weight, gender, ethnicity and body shape. As the exposed BSA depends on clothing, finally an approach is presented which aims to calculate the size of body parts released by real garments. In summary, this paper will enable future researchers to quantify the exposed BSA by best matching their study population and consequently investigate risks caused by solar UV exposure.

Parametric human modelling to determine body surface area covered by sun-protective clothing

Solar ultraviolet radiation (UVR) is the main environmental risk-factor for cancer of the skin. Sun-protective clothing provides a physical barrier that reduces the UVR dose reaching the skin and European and Australian standards for sun-protective clothing set minimum clothing coverage requirements. Body Surface Area Coverage by clothing (BSAC) is calculated by means of indirect or direct methods, which are laborious and do not support computer-based apparel design. To support the sun-safe specification and design of garments, parametric digital human models and protective clothing mesh covering the minimum Body Surface Area specified in AS/NZS 4399:2017, were created making use of MakeHuman v1.1.1 and Blender software. The Whole Body Surface Area (WBSA) and the BSAC were calculated employing code developed in Blender. Thus, different groups of subjects were analysed to explore BSAC. The method assists in the evaluation of exposed body areas in a wider spectrum of different occupations. Practitioner summary: Sun-protective clothing provides a physical barrier that reduces the UVR dose reaching the skin's surface. Body Surface Area Coverage (BSAC) by clothing is an important determinant of the sun protective capabilities of a garment. In this study, BSAC is calculated using parametric digital human modelling. Abbreviation: UVR: (Solar) ultraviolet radiation; DHM: digital human modeling; BSA: body surface area; BSAC: body surface area coverage (by clothing); BSANC: body surface area not covered (by clothing); WBSA: whole body surface area; BCC: basal cell carcinoma; SCC: squamous cell carcinoma; UPF: ultraviolet protection factor; GPF: garment protection factor.

Studying third-parties and environments: New Zealand sun-safety research

Wearable cameras have been used to study health behaviours, but their utility in assessing third-party behaviours and the built environment is uncertain. This paper reports on the feasibility of using wearable cameras for this purpose in a study of sun-protective behaviours and shade availability during school lunch-breaks. The Kids'Cam study provided 168 children (aged 11-13 years), recruited from 16 randomly selected schools in the Wellington region of New Zealand, with wearable cameras. The devices automatically captured images every 7 s from the child's perspective. Images captured during school lunch-breaks by a random sample of 15 children who took part during terms 4 and 1 (October 2014-April 2015) were selected and assessed for usability. The feasibility of studying third-party sun-protective behaviours and school shade availability was assessed for a subset of 320 images. Of the 3492 eligible lunch-break images, 96.4% were useable; the remainders were excluded due to obstruction, blurriness or unsuitable camera position. Overall, 1278 children and 108 shade structures were observed in the sample images. The use of shade, hats, sleeves, collars and sunglasses could be determined for 97.0%, 77.2%, 74.4%, 47.6% and 54.9% of children, respectively. All shade structures could be classified according to type, and canopy composition could be assessed for 95.4% of structures. Wearable cameras are a feasible tool for assessing sun-safety, particularly shade availability, hat wearing and shade use. This methodology could be used to objectively study other third-party health-related behaviours, and other features of the built environment.

Influence of Air Temperature on the UV Exposure of Different Body Sites Due to Clothing of Young Women During Daily Errands

Clothing is one of the main influencing factors for personal ultraviolet radiation (UVR) exposure. Despite that, little attention was put on this topic till now. In this study, the clothing habits of young females have been investigated in dependence of meteorological conditions. Observations were made from spring to autumn during daylight in the urban region of Vienna, Austria. For this, a scheme dividing the body into six different sections was developed as well as a coding scale that corresponds to the different garments and indicates the body sites that are exposed. It was found that air temperature is the dominating factor for exposure. With increasing temperature, the first area of the body to be exposed to solar UVR is, aside from face and hands, the décolleté, followed by nape, ankles, instep and forearms. Observations further indicate that the frequency of people's being outdoors decreases significantly at temperatures higher than 30°C. This paper provides detailed frequency distributions of uncovered body sites in dependence of temperature. These can be used together with measurements of temperature and UVR to calculate the relative exposure at any time and at many locations, and could help to explain the body distribution of UVR caused skin alterations.

Sun Protection Among New Zealand Primary School Children

Schools are an important setting for raising skin cancer prevention awareness and encouraging sun protection. We assessed the clothes worn and shade used by 1,278 children in eight schools in the Wellington region of New Zealand. These children were photographed for the Kids'Cam project between September 2014 and March 2015 during school lunch breaks. Children's mean clothing coverage (expressed as a percentage of body area covered) was calculated. Data on school sun-safety policies were obtained via telephone. Mean total body clothing coverage was 70.3% (95% confidence interval = 66.3%, 73.8%). Body regions with the lowest mean coverage were the head (15.4% coverage), neck (36.1% coverage), lower arms (46.1% coverage), hands (5.3% coverage), and calves (30.1% coverage). Children from schools with hats as part of the school uniform were significantly more likely to wear a hat (52.2%) than children from schools without a school hat (2.7%). Most children (78.4%) were not under the cover of shade. Our findings suggest that New Zealand children are not sufficiently protected from the sun at school. Schools should consider comprehensive approaches to improve sun protection, such as the provision of school hats, sun-protective uniforms, and the construction of effective shade.

Children's everyday exposure to food marketing: an objective analysis using wearable cameras

Background

Over the past three decades the global prevalence of childhood overweight and obesity has increased by 47%. Marketing of energy-dense nutrient-poor foods and beverages contributes to this worldwide increase. Previous research on food marketing to children largely uses self-report, reporting by parents, or third-party observation of children’s environments, with the focus mostly on single settings and/or media. This paper reports on innovative research, Kids’Cam, in which children wore cameras to examine the frequency and nature of everyday exposure to food marketing across multiple media and settings.

Methods

Kids’Cam was a cross-sectional study of 168 children (mean age 12.6 years, SD = 0.5) in Wellington, New Zealand. Each child wore a wearable camera on four consecutive days, capturing images automatically every seven seconds. Images were manually coded as either recommended (core) or not recommended (non-core) to be marketed to children by setting, marketing medium, and product category. Images in convenience stores and supermarkets were excluded as marketing examples were considered too numerous to count.

Results

On average, children were exposed to non-core food marketing 27.3 times a day (95% CI 24.8, 30.1) across all settings. This was more than twice their average exposure to core food marketing (12.3 per day, 95% CI 8.7, 17.4). Most non-core exposures occurred at home (33%), in public spaces (30%) and at school (19%). Food packaging was the predominant marketing medium (74% and 64% for core and non-core foods) followed by signs (21% and 28% for core and non-core). Sugary drinks, fast food, confectionary and snack foods were the most commonly encountered non-core foods marketed. Rates were calculated using Poisson regression.

Conclusions

Children in this study were frequently exposed, across multiple settings, to marketing of non-core foods not recommended to be marketed to children. The study provides further evidence of the need for urgent action to reduce children’s exposure to marketing of unhealthy foods, and suggests the settings and media in which to act. Such action is necessary if the Commission on Ending Childhood Obesity’s vision is to be achieved.

Electronic supplementary material

The online version of this article (doi:10.1186/s12966-017-0570-3) contains supplementary material, which is available to authorized users.