Daylight and Electric Lighting in Primary and Secondary School Classrooms in the UK-An Observational Study.

Only a few recent studies report direct assessment or monitoring of light levels in the indoor learning environment, and no consensus exists on minimum exposures for children's health. For instance, myopia is a common progressive condition, with genetic and environmental risk factors. Reduced daylight exposure, electric lighting changes, increased near-work for school children, greater academic focus, and use of display screens and white boards may have important detrimental influences.

Low-dose daylight exposure induces nitric oxide release and maintains cell viability in vitro.

Any potential positive effects conferred via sunlight exposure have to be carefully balanced against carcinogenic effects. Here we provide evidence UK sunlight exposure upregulates the cardio protectant nitric oxide (NO) within in vitro skin cell lines with negligible increases in DNA damage and cell death at 1 SED, when compared against unexposed samples. The whole of the ultraviolet A (UV-A) spectrum appears to be responsible for NO release, with efficiency higher at exposures closer to shorter UV-A wavelengths and decreasing with wavelength increases.

Post-exposure persistence of nitric oxide upregulation in skin cells irradiated by UV-A.

Evidence suggests that exposure to UV-A radiation can liberate nitric oxide from skin cells eliciting vasodilation in-vivo. However, the duration of nitric oxide release in skin cells after UV exposure is not well studied, with emphasis on UV-B mediated iNOS upregulation. The current study demonstrated persistence of nitric oxide release in a dark reaction after moderate UV-A exposure, peaking around 48 h post exposure; this effect was shown in keratinocytes, fibroblasts and endothelial cells from neonatal donors and keratinocytes from aged donors and confirmed the hypothesis that UV-A exposure appeared to upregulate cNOS alongside iNOS.

Assessment of the Light Exposures of Shift-working Nurses in London and Dortmund in Relation to Recommendations for Sleep and Circadian Health.

Shift work causes disruption to circadian physiological processes in the human body, and desynchronization from the natural day-and-night rhythm. Circadian disruption is thought to explain the associations between shift work and various long-term diseases; light is an unrivalled synchronizer (or Zeitgeber) of circadian processes and inappropriate light exposure plausibly plays a critical role in the development of health impairments. As published measurement data on the actual light environments encountered by shift workers are sparse, nurses working in two hospitals in London (UK) and Dortmund (Germany) wore light-logging dosimetry devices to measure personal light exposures continuously over a week in three different seasons.

Impact of COVID-19 Lockdown on Sun Exposure of UK Office Workers.

The impact of lockdown due to the COVID-19 pandemic in April-June 2020 on UV exposure of office workers was assessed using an online survey on time spent outdoors and environmental data for different locations in the UK. Without the need for commuting and with the flexibility of homeworking, weekday time spent outdoors was higher in the 2020 lockdown than in the same period in 2017. The weekday erythema effective radiant exposure was higher in 2020 due to an additional 45 min outdoors in the late afternoon that was not observed in 2017 and high UV levels due to extremely sunny weather in spring.

Global verification of a model for determining daylight photodynamic therapy dose.

Daylight photodynamic therapy is an effective treatment for actinic keratoses and relies on a minimum PpIX-effective light exposure dose being delivered during treatment. As such, daylight dosimetry is an important aspect of this treatment. Relatively simple measurements of illuminance may be converted to PpIX-effective irradiance, and subsequently exposure dose, via a conversion model (the O'Mahoney model).

Survey of Home-Use UV Disinfection Products.

The COVID-19 pandemic provided a commercial opportunity for traders marketing a range of ultraviolet (UV) radiation products for home-use disinfection. Due to concerns about the efficacy of such products and the potential for harmful levels of UV exposure to people, a range of products were purchased from on-line trading platforms. Spectral irradiance measurements were carried out to determine whether the products could be effective against the SARS-CoV-2 virus and whether they were likely to exceed internationally agreed exposure limits.

Impact of High Solar UV Radiant Exposures in Spring 2020 on SARS-CoV-2 Viral Inactivation in the UK.

Potential for SARS-CoV-2 viral inactivation by solar UV radiation in outdoor spaces in the UK has been assessed. Average erythema effective and UV-A daily radiant exposures per month were higher (statistically significant, P < 0.05) in spring 2020 in comparison with spring 2015-2019 across most of the UK, while irradiance generally appeared to be in the normal expected range of 2015-2019.

SmartPDT®: Smartphone enabled real-time dosimetry via satellite observation for daylight photodynamic therapy.

Background: Actinic keratosis (AK) affects one quarter of over 60  year olds in Europe with the risk of transforming into invasive squamous cell carcinoma. Daylight photodynamic therapy (dPDT) is an effective and patient preferred treatment that uses sunlight to clear AK. Currently, there is no standardised method for measuring the light received during treatment.

In-Flight UV-A Exposure of Commercial Airline Pilots.

Understanding UV exposure is essential for the assessment of its contribution to the occupational risk of pilots developing ocular and skin pathologies. The objective of this observational study was to measure the UV exposure of pilots flying between the United Kingdom and a range of destinations at three different seasons. The in-flight UV exposure of pilots was measured on 322 Monarch Airlines short-haul flights on the Airbus A321-231 and Airbus A320-214 to 31 destinations, mostly in Europe, from 4 UK airports in September 2016-August 2017.

Measuring Daylight: A Review of Dosimetry in Daylight Photodynamic Therapy.

Successful daylight photodynamic therapy (DPDT) relies on the interaction of light, photosensitisers and oxygen. Therefore, the 'dose' of light that a patient receives during treatment is a clinically relevant quantity, with a minimum dose for effective treatment recommended in the literature. However, there are many different light measurement methods used in the published literature, which may lead to confusion surrounding reliable and traceable dose measurement in DPDT, and what the most appropriate method of light measurement in DPDT might be.

Method for Measurements of Terrestrial Ultraviolet Radiation on Inclined Surfaces in Personal Dosimetry Field Studies.

Understanding personal ultraviolet radiation (UVR) exposure is essential for the evaluation of the health risks and benefits; however, personal dosimetry could be challenging in large-scale or/and long-term population studies. Alternatively, personal exposure could be simulated using three-dimensional models and lifestyle surveys together with data on a body position with respect to the sun. These models require a real-time input on local environmental UVR.

Ultraviolet radiation exposure during daylight Photodynamic Therapy.

Background: Daylight photodynamic therapy (dPDT) is an effective treatment for field-change actinic keratoses (AK), with similar efficacy to conventional PDT but lower patient pain scores. Whilst AK occur consequent to chronic solar ultraviolet (UV) exposure, paradoxically solar visible radiation is used during PDT.

Objectives: To investigate the nature and levels of UV exposure, both erythemal UV and UVA, occurring during dPDT.

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.

Optical performance characterization of light-logging actigraphy dosimeters.

There are several wearable products specially developed or marketed for studying sleep, circadian rhythms, and light levels. However, new recommendations relating to human physiological responses to light have changed what measurements researchers may demand. The performances of 11 light-logging dosimeters from eight manufacturers were compared.

Use of illuminance as a guide to effective light delivery during daylight photodynamic therapy in the U.K.

Background: Daylight PDT (dPDT) is an effective and nearly painless treatment for field-change actinic keratosis. Measuring the protoporphyrin-IX (PpIX)-weighted exposure dose can give an indication of when conditions are most viable for effective dPDT. It would be advantageous for practitioners if more detailed information of exposure dose and appropriate treatment conditions were available.

Validation and in vivo assessment of an innovative satellite-based solar UV dosimeter for a mobile app dedicated to skin health.

We present an innovative satellite-based solar UV (ultraviolet) radiation dosimeter with a mobile app interface that has been validated by exploiting both ground-based measurements and an in vivo assessment of the erythemal effects on some volunteers having controlled exposure to solar radiation. The app with this satellite-based UV dosimeter also includes other related functionalities such as the provision of safe sun exposure time updated in real-time and end exposure visual/sound alert. Both validations showed that the system has a good accuracy and reliability needed for health-related applications.

Sunglass Filter Transmission and Its Operational Effect in Solar Protection for Civilian Pilots.

Introduction: The ocular effects of excess solar radiation exposure are well documented. Recent evidence suggests that ocular ultraviolet radiation (UVR) exposure to professional pilots may fall outside international guideline limits unless eye protection is used. Nonprescription sunglasses should be manufactured to meet either international or national standards.

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.

Occupational Ocular UV Exposure in Civilian Aircrew.

Introduction: Ultraviolet radiation (UVR) increases with altitude; however, there are a number of other factors which may influence ocular exposure during flight. The aim of this study was to assess ocular UVR exposure of pilots in airline and off-shore helicopter operations on different aircraft types and to compare with exposure in a typical office environment.

Method: In-flight data were captured on equipment including a CCD array spectroradiometer on five return sector European airline flights and one transatlantic flight from London Gatwick in addition to four helicopter flights from Aberdeen Dyce airport.

DYNAMIC RESPONSE OF CCD ARRAY SPECTRORADIOMETERS.

A number of factors affect the measurements by charge coupled (CCD) array spectroradiometers, including stray light, dynamic response and ambient temperature. The departure from linearity was assessed for four CCD array spectroradiometers and linearity correction calculated with standard uncertainties error estimates. A fixed irradiance source supplemented with neutral density filters was used to allow tests to cover a full range of operational conditions.

International Intercomparison of Solar UVR Spectral Measurement Systems in Melbourne in 2013.

Monitoring ambient solar UVR levels provides information on how much there is in both real time and historically. Quality assurance of ambient measurements of solar UVR is critical to ensuring accuracy and stability and this can be achieved by regular intercomparisons of spectral measurement systems with those of other organizations. In October and November of 2013 a solar UVR spectroradiometer from Public Health England (PHE) was brought to Melbourne for a campaign of intercomparisons with a new Bentham spectrometer of Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) and one at the Australian Bureau of Meteorology (BOM), supported by New Zealand's National Institute for Water and Atmosphere (NIWA).