Sun exposure of indoor workers in the UK - survey on the time spent outdoors.

Assessment of ultraviolet (UV) exposure is essential for evaluation of the risks and benefits to optimise public health outcomes. The exposure depends on available environmental UV radiation and individual behaviour, and it can be obtained from dosimetry studies; however, the use of dosimeters is often not feasible for large population groups or over long periods of time. In this study, a lifestyle questionnaire has been used to obtain information on the time spent outdoors by indoor workers that could be used in combination with dosimetry studies in smaller targeted groups to quantify UV exposure for health risk/benefit analysis. 894 office and laboratory workers at the Public Health England, UK, responded to the survey. Questions addressed the time of day and the duration of time; staff were outdoors on weekdays, at weekends and during holidays. The majority of the responders spent negligible time outdoors on weekdays. Outdoor activities before and after work were constrained by the work pattern and commuting. The average time for those who go outdoors before and after commuting was 22.5 ± 16.2 min and 30.4 ± 21.4 min, respectively. Only 7% of participants regularly spent their lunch break outdoors for 21.5 ± 12.2 min and weekday exposure may contribute less than 13% of the daily available erythema dose. At the weekend, on average responders spend 5.0 ± 2.6 h outdoors over the two days: if taken around midday, it accounts for approximately 50% of available UV exposure. In winter months in the UK, November to March, the combination of very low environmental UV and low ambient temperatures results in negligible UV exposure. Holidays contributed to the majority of the annual UV exposure. In summer, 45% of responders went to destinations where the UV levels may be up to 2 times higher than in the UK; durations of overseas holidays are also longer than UK breaks. The UV dose from two weeks of holiday in extreme UV index level destinations could be comparable to a 1.5-2 summer months holiday in the UK. The survey data were validated with 6 months of dosimetry within the same cohort; very strong and strong correlation was found between the survey and measurements. This shows that a lifestyle survey can be used in combination with targeted dosimetry studies in small groups to obtain information about the time spent outdoors.

Long term variations in erythema effective solar UV at Chilton, UK, from 1991 to 2015.

In this paper erythema effective UV radiant exposure data from the PHE solar network Chilton site for the 25 year period from 1991 to 2015 are presented. The year with the highest average daily erythema effective radiant exposure was 2003 at 1577 J m-2 and the year with the lowest average daily radiant exposure was 2010 at 1149 J m-2. Overall, the average daily radiant exposure per year ranged from 5655 J m-2 to 9.98 J m-2 with the average being 1306 J m-2. A preliminary analysis of the data set is carried out. A statistically significant (p = 0.01) increase in annual radiant exposure of 4.4% per year was observed from 1991-1995. Thereafter a small decrease in annual erythema effective radiant exposure of 0.8% (p = 0.002) per year was observed from 1995-2015 with a slightly faster rate of decrease from 2000-2015 of 1.0% (p = 0.007) per year. In terms of seasonal analyses, a statistically significant increase in erythema effective UV radiant exposure of 5.1% (p = 0.02) per year in the summer during 1991-1995 has been found along with small decreases in spring and summer during 1995-2015 (-1.0%; p = 0.01 and -0.7%; p = 0.01 respectively) and 2000-2015 (-1.1%; p = 0.03 and -1.2%; p = 0.003 respectively). The data suggest that the erythema effective UV dose available for impacting public health has been decreasing in recent years.

Low-energy light bulbs, computers, tablets and the blue light hazard.

The introduction of low energy lighting and the widespread use of computer and mobile technologies have changed the exposure of human eyes to light. Occasional claims that the light sources with emissions containing blue light may cause eye damage raise concerns in the media. The aim of the study was to determine if it was appropriate to issue advice on the public health concerns. A number of sources were assessed and the exposure conditions were compared with international exposure limits, and the exposure likely to be received from staring at a blue sky. None of the sources assessed approached the exposure limits, even for extended viewing times.

Safety of light emitting diodes in toys.

Light emitting diodes (LEDs) are increasingly being used in toys. An assessment methodology is described for determining the accessible emission limits for the optical radiation from the toys, which takes account of expected use and reasonably foreseeable misuse of toys. Where data are available, it may be possible to assess the toy from the data sheet alone. If this information is not available, a simple measurement protocol is proposed.

Occupational UVR skin protection by make-up.

New legislation has been introduced in the Member States of the European Union, covering worker exposure to artificial optical radiation. Use of make-up could reduce the ultraviolet hazard level and provide additional protection for skin against UV radiation (UVR). This is particularly important in entertainment and filming where intentional exposure of the actors and presenters to the very intense light sources may be required for extended periods of time. This document presents the assessment of UVR protection of make-up used in entertainment and demonstrates that the protection level varies considerably for different luminaires and application techniques. An important practical implication of this finding is that make-up alone cannot be considered as a reliable protection measure against skin exposure to actinic UV.

Assessment of personal exposures to optical radiation in large entertainment venues.

Workplace exposure to optical radiation from artificial sources is regulated in Europe under the Artificial Optical Radiation Directive 2006/25/EC implemented in the UK as The Control of Artificial Optical Radiation at Work Regulations 2010. The entertainment environment often presents an extremely complex situation for the assessment of occupational exposures. Multiple illumination sources, continuously changing illumination conditions and people moving during performances add further complexity to the assessment. This document proposes a methodology for assessing the risks arising from exposure to optical radiation and presents detailed case studies of practical assessment for two large entertainment venues.

Temporal variation of erythemally effective UVB/UVA ratio at Chilton, UK.

An analysis of the temporal variation in the erythemally weighted UVB/UVA irradiance ratio using spectral data collected from a monitoring site in Chilton, UK (51°N) for the 5-y period from 2004 to 2008 is presented. The variation in the diurnal ratio was found to be bell-shaped, with minima on average 1 h after sunrise and before sunset. The minima were found to be indicative of the point at which UVB becomes undetectable by the spectroradiometer and therefore the outer boundary of useful data. A potential flaw entailed in the erythemal weighting of low-level spectral UV data is described. The peak daily ratio value was found to have a bell-shaped distribution over the course of a year with a maximum in July rather than at the summer solstice-a result explained by the ozone cycle. The peak daily ratio was found to vary by a factor of 4 over the course of the year; this range of variation was also found to occur over a single day in the summer.

Optical radiation emissions from compact fluorescent lamps.

There is a drive to energy efficiency to mitigate climate change. To meet this challenge, the UK Government has proposed phasing out incandescent lamps by the end of 2011 and replacing them with energy efficient fluorescent lighting, including compact fluorescent lamps (CFLs) with integrated ballasts. This paper presents a summary of an assessment conducted by the Health Protection Agency in March 2008 to evaluate the optical radiation emissions of CFLs currently available in the UK consumer market. The study concluded that the UV emissions from a significant percentage of the tested CFLs with single envelopes may result in foreseeable overexposure of the skin when these lamps are used in desk or task lighting applications. The optical output of all tested CFLs, in addition to high-frequency modulation, had a 100-Hz envelope with modulation in excess of 15%. This degree of modulation may be linked to a number of adverse effects.

Assessment of sun protection for children's summer 2005 clothing collection.

Overexposure to solar ultraviolet radiation (UVR) in childhood is considered to be a critical factor for developing skin cancer in later life. Clothing may offer a simple and effective means of protection against overexposure to the sun, but its use has often been underrated in public opinion. The Health Protection Agency, in close collaboration with a number of UK retailers, conducted a study to evaluate the UVR protection characteristics of the summer 2005 collection of children's clothing for outdoor activity. The current paper presents a summary of the assessment and the effects of stretching and wetting on the Ultraviolet Protection Factor (UPF) rating of children's clothing. The results demonstrate the need for better public guidance in sun protection of children and more comprehensive evaluation procedures for sun protection provided by clothing.

Radiation and chemical degradation of UVR protection characteristics of fabrics.

Clothing can provide substantial protection against solar ultraviolet radiation (UVR) and quantifying the amount of protection can have useful applications to recreational, occupational and medical situations. However, exposure of fabrics to sunlight and sea water can alter their physical and chemical properties, resulting in a change of UVR attenuation characteristics. The objective of the current study was to evaluate the effects of environmental degradation of fabrics on their UVR protection characteristics. The methodologies applied in this study can be used also for the assessment of protective clothing against occupational exposure.

A new methodology for the assessment of hand protection from ultraviolet exposure.

A number of industrial applications and public services involve occupational exposure to ultraviolet radiation (UVR) from a variety of lamps and lasers. The aim of this study was to develop a methodology for the assessment of the UV protection level for disposable gloves. Glove UV protection factor is defined as a time-scale increase in exposure permitted for the hand protected by a glove with respect to an unprotected hand. Our study showed that for all tested gloves a change in UVR attenuation with stretching is characteristic for the type of glove material and can be included as a scaling factor in the definition of UVR protection. Glove material has a bigger effect on UVR protection level than variations in the glove thickness or its colour. Examples of assessment of the 'worst case scenario' are compared with the protection level against a number of sources, together with the guidance on a simplified evaluation protocol. An application-specific assessment, illustrated for 'SmartWater' forensic examinations and biological trans-illuminators, demonstrates that some gloves provide inadequate protection against occupational UV exposure.

Relationship between local temperature and heat transfer through the hand and wrist.

The heat uptake that resulted from immersing the hand and wrist into a water-filled calorimeter maintained at temperatures between 37-40 degrees C was measured under standard conditions in a group of eight subjects of either sex. The rate of heat transfer (W) increased exponentially with temperature and was a function of hand or body size and age, but not sex. The heat transfer rate normalized to hand mass (W.kg-1) was determined by temperature and age: best-fit mean values (and 95% confidence limits of the population) were 6.0 W.kg-1 (3.2-11.2 W.kg-1) at an immersion temperature of 37 degrees C and 25.4 W.kg-1 (13.7-47.0 W.kg-1) at 40 degrees C. The application of these results to limits on specific energy absorption rate induced in the hands and wrists by radiofrequency dielectric heat sealer welders is discussed.

Gas discharge ion source III. Modified Berkeley multifilament ion source.

Total ion current, ion energy, mass and current density distributions, and the impurity content of the ion beams produced by a modified Berkeley multifilament ion source (MFIS) were measured as a function of source configuration, gas pressure, and operating conditions: the ''best'' configuration produced beams of 200 mA or more at pressures between 0.40 and 2.0 Pa. In comparison with earlier studies of duoplasmatron and duopigatron sources, the MFIS beams contained less D(+), only ca. 33%, but the beams had much narrower energy distributions and flatter current density distributions. The beams contained 1%-2% impurities which consisted mainly of masses 18, 20, and 22.

Gas discharge ion source. II. Duopigatron.

Ion source performance characteristics consisting of total ion current, ion energy distribution, mass distribution, and ion current density distribution have been measured for several models of a duopigatron. Variations on the duopigatron design involved plasma expansion cup material and dimensions, secondary cathode material, and interelectrode spacings. Of the designs tested, the one with a copper and molybdenum secondary cathode, and a mild steel plasma expansion cup proved to give the best results. The ion current density distribution was peaked at the center of the plasma expansion cup and fell off to 80% of the peak value at the cup wall for a cup 15.2 mm deep. A total ion current of 180 mA consisting of 60%-70% atomic ions was produced with an arc current of 20 A and source pressure of 9.3 Pa. More shallow cups produced a larger beam current and a more sharply peaked ion current density distribution. Typical ion energy distributions were bellshaped curves with a peak 10-20 V below anode potential and with ion energies extending 30-40 V on either side of the peak.