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Acute lymphoblastic leukemia (ALL) is the most common type of cancer in children (age 0-14 years); however, the etiology remains incompletely understood. Several environmental exposures have been linked to risk of childhood ALL, including air pollution. Closely related to air pollution and human development is artificial light at night (ALAN), which is believed to disrupt circadian rhythm and impact health. We sought to evaluate outdoor ALAN and air pollution on risk of childhood ALL. The California Linkage Study of Early-Onset Cancers is a large population-based case-control in California that identifies and links cancer diagnoses from the California Cancer Registry to birth records. For each case, 50 controls with the same year of birth were obtained from birth records. A total of 2,782 ALL cases and 139,100 controls were identified during 2000-2015. ALAN was assessed with the New World Atlas of Artificial Night Sky Brightness and air pollution with an ensemble-based air pollution model of particulate matter smaller than 2.5 microns (PM2.5). After adjusting for known and suspected risk factors, the highest tertile of ALAN was associated with an increased risk of ALL in Hispanic children (odds ratio [OR] = 1.15, 95% confidence interval [CI] 1.01-1.32). There also appeared to be a borderline association between PM2.5 level and risk of ALL among non-Hispanic White children (OR per 10 µg/m3 = 1.24, 95% CI 0.98-1.56). We observed elevated risk of ALL in Hispanic children residing in areas of greater ALAN. Further work is needed to understand the role of ALAN and air pollution in the etiology of childhood ALL in different racial/ethnic groups.

In nature, light is a key driver of animal behaviour and physiology. When studying captive or laboratory animals, researchers usually expose animals to a period of darkness, to mimic night. However, 'darkness' is often poorly quantified and its importance is generally underappreciated in animal research. Even small differences in nocturnal light conditions can influence biology. When light levels during the dark phase are not reported accurately, experiments can be impossible to replicate and compare. Furthermore, when nocturnal light levels are unrealistically dark or bright, the research is less ecologically relevant. Such issues are exacerbated by huge differences in the sensitivity of different light meters, which are not always described in study methods. We argue that nocturnal light levels need to be reported clearly and precisely, particularly in studies of animals housed indoors (e.g. '

Artificial light at night (ALAN) is increasing in extent and intensity across the globe. It has been shown to interfere with animal sensory systems, orientation and distribution, with the potential to cause significant ecological impacts. We analysed the locations of 102 mountain lions (Puma concolor) in a light-polluted region in California. We modelled their distribution relative to environmental and human-disturbance variables, including upward radiance (nearby lights), zenith brightness (sky glow) and natural illumination from moonlight. We found that mountain lion probability of presence was highly related to upward radiance, that is, related to lights within approximately 500 m. Despite a general pattern of avoidance of locations with high upward radiance, there were large differences in degree of avoidance among individuals. The amount of light from artificial sky glow was not influential when included together with upward radiance in the models, and illumination from moonlight was not influential at all. Our results suggest that changes in visibility associated with lunar cycles and sky glow are less important for mountain lions in their selection of light landscapes than avoiding potential interactions with humans represented by the presence of nearby lights on the ground. This article is part of the theme issue 'Light pollution in complex ecological systems'. [ABSTRACT FROM AUTHOR]

The presence and proportions of photopigments, which are responsible for the visual and physiological effects of light, vary between taxonomic groups. This leads to differing wavelength sensitivities ranging from ultraviolet (UV; <400 nm) to infrared (IR; >780 nm) and complicates the balancing of spectra used for outdoor lighting to maximize human visual performance while mitigating light pollution effects on wildlife. I developed a database of spectral response information for terrestrial wildlife to create generalized spectral response curves by taxonomic phylum, class, and order. Existing data on species visual sensitivity were collected from previously published research that used behavioral responses, electroretinograms (ERGs), and reflectance within the eye. Resulting summaries of photopigment peak sensitivities (n=968) and sensitivity curves (n=177) allow for general observations. Overall, longer wavelengths provide the highest possibility for supporting human visual performance at night while reducing intrusive overlap with the vision of other species, because many taxonomic groups are sensitive to light in the blue and into the ultraviolet. Comparison of average response curves at the class level and the spectral power distribution of lamps suggests that spectral tuning might reduce the apparency of the lowest correlated color temperature (CCT) lamps to insects, spiders, and non-human mammals the most, with substantial but smaller reductions for reptiles, birds, and amphibians. Spectral tuning, most simply by reducing CCT, should be considered an additional benefit to be used in concert with other mitigation measures such as dimming, shielding, and part-night lighting. [ABSTRACT FROM AUTHOR]

New infrastructure development in previously natural environments is introducing light pollution to habitats at an unprecedented rate, which has the potential to be devastating for native insect assemblages.We evaluated insect attraction to three lamp types emitting different spectra of light (white, yellow‐filtered and amber‐filtered ~3000 K LED lamps) and an unlit control in a lowland forest site in the northern Peruvian Amazon previously naïve to artificial illumination.Lamp type was the only variable included in the most parsimonious models explaining morphospecies richness and abundance for all insects combined and for eight different insect orders. White lamps (3200 K) attracted far more insects, both morphospecies and individuals, including groups containing important vectors of pathogens, bacteria or parasites, than either yellow (2700 K) or amber (2200 K) lamps.Amber lamps attracted the fewest morphospecies and individuals overall but were the most attractive for a limited group of insects, including elaterid beetles (click beetles) and mycetophilid flies (fungus flies).While period of night was not a significant predictor of morphospecies richness or abundance, different assemblages of insects were collected during two different sampling periods (18:00–20:00 and 03:00–05:00).We strongly recommend that new infrastructure development projects introducing ALAN to light‐naïve tropical forests use filtered amber LED lamps with no blue and minimal green light content in outdoor lighted areas. Similarly, operators should develop outdoor lighting plans that include overall reduction of nocturnal lighting and impact mitigation measures. These recommendations should also be used to retrofit existing infrastructure including roads and human settlements. El desarrollo de nuevas infraestructuras en entornos previamente naturales está introduciendo contaminación lumínica en esos hábitats a una taza sin precedentes, la cual tiene el potencial de ser particularmente devastadora para las comunidades de insectos nativos.Evaluamos la atracción de insectos a tres tipos de lámparas que emiten diferentes espectros de luz (lámparas LED blancas de ~3000K sin filtro, con un filtro amarillo y con un filtro ámbar para limitar o eliminar los espectros azules de luz emitidos) y un control sin luz en un sitio de bosque bajo en el norte de la Amazonía peruana, previamente sin iluminación artificial.El tipo de lámpara fue la única variable incluida en los modelos más parsimonicos que explican la riqueza y abundancia de morfoespecies para todos los insectos combinados y para ocho órdenes diferentes de insectos. Las lámparas blancas (3200K) atrajeron muchos más insectos, morfoespecies e individuos, incluyendo grupos conocidos por contener vectores importantes de patógenos, bacterias o parásitos, que las lámparas de color amarillo (2700K) o ámbar (2200K).Las lámparas ámbar atrajeron la menor cantidad de morfoespecies e individuos en general, pero fueron las luces más atractivas para un grupo limitado de insectos, incluyendo a los escarabajos elatéridos (escarabajos clic) y las moscas micetofílidas (moscas de los hongos).Si bien el período de la noche no fue un predictor significativo de la riqueza o abundancia de morfoespecies, se colectaron diferentes ensamblajes de insectos durante los dos períodos de muestreo (18: 00‐20: 00 y 03: 00‐05: 00).Recomendamos enfáticamente que los nuevos proyectos de desarrollo de infraestructura que introduzcan ALAN a bosques sin luces artificiales utilicen luces LED con filtro ámbar sin espectro azul y muy poco espectro verde en áreas iluminadas al aire libre. Del mismo modo, los operadores deben desarrollar un plan de iluminación al aire libre que incluya la reducción general de la iluminación nocturna y métodos de mitigación de impactos. Estas recomendaciones también deben usarse para modernizar la infraestructura existente, incluidas las carreteras y los asentamientos humanos. [ABSTRACT FROM AUTHOR]

Formany decades, the spectral composition of lighting was determined by the type of lamp, which also influenced potential effects of outdoor lights on species and ecosystems. Light-emitting diode (LED) lamps have dramatically increased the range of spectral profiles of light that is economically viable for outdoor lighting. Because of the array of choices, it is necessary to develop methods to predict the effects of different spectral profiles without conducting field studies, especially because older lighting systems are being replaced rapidly. We describe an approach to predict responses of exemplar organisms and groups to lamps of different spectral output by calculating an index based on action spectra from behavioral or visual characteristics of organisms and lamp spectral irradiance. We calculate relative response indices for a range of lamp types and light sources and develop an index that identifies lamps that minimize predicted effects as measured by ecological, physiological, and astronomical indices. Using these assessment metrics, filtered yellow-green and amber LEDs are predicted to have lower effects on wildlife than high pressure sodium lamps, while blue-rich lighting (e.g., K = 2200) would have greater effects. The approach can be updated with new information about behavioral or visual responses of organisms and used to test new lighting products based on spectrum. Together with control of intensity, direction, and duration, the approach can be used to predict and then minimize the adverse effects of lighting and can be tailored to individual species or taxonomic groups. [ABSTRACT FROM AUTHOR]

Light sources attract nocturnal flying insects, but some lamps attract more insects than others. The relation between the properties of a light source and the number of attracted insects is, however, poorly understood. We developed a model to quantify the attractiveness of light sources based on the spectral output. This model is fitted using data from field experiments that compare a large number of different light sources. We validated this model using two additional datasets, one for all insects and one excluding the numerous Diptera. Our model facilitates the development and application of light sources that attract fewer insects without the need for extensive field tests and it can be used to correct for spectral composition when formulating hypotheses on the ecological impact of artificial light. In addition, we present a tool allowing the conversion of the spectral output of light sources to their relative insect attraction based on this model. [ABSTRACT FROM AUTHOR]

• Light pollution is an increasing worldwide pressure for biodiversity, especially contributing to habitat loss and fragmentation. • Green infrastructure (i.e. ecological networks policies) should consider nighttime darkness. • A 4-step operational process could be adopted to identify, preserve, restore and assess dark infrastructure. • Several dark infrastructure were already identified in both urban and natural areas, although some knowledge gaps still need to be filled. Artificial light at night (ALAN) has been massively deployed worldwide and has become a major environmental pressure for biodiversity, especially contributing to habitat loss and landscape fragmentation. To mitigate these latter, green and blue infrastructure policies have been developed throughout the world based on the concept of ecological networks, a set of suitable interconnected habitats. However, currently, these nature conservation policies hardly consider the adverse effects of ALAN. Here, we promote the integration of darkness quality within the 'green and blue infrastructure', to implement a 'dark infrastructure'. Dark infrastructure should be identified, preserved and restored at different territorial levels to guarantee ecological continuities where the night and its rhythms are as natural as possible. For this purpose, we propose an operational 4-steps process that includes 1) Mapping of light pollution in all its forms and dimensions in relation to biodiversity, 2) Identifying the dark infrastructure starting or not from the already identified green/blue infrastructure, 3) Planning actions to preserve and restore the dark infrastructure by prioritizing lighting sobriety and not only energy saving, 4) Assessing the effectiveness of the dark infrastructure with appropriate indicators. Dark infrastructure projects have already been created (for example in France and Switzerland) and can serve as case studies for both urban and natural areas. The deployment of dark infrastructure raises many operational and methodological questions and stresses some knowledge gaps that still need to be addressed, such as the exhaustive mapping of light pollution and the characterization of sensitivity thresholds for model species. [ABSTRACT FROM AUTHOR]

The physiology and behavior of most life at or near the Earth's surface has evolved over billions of years to be attuned with our planet's natural light–dark cycle of day and night. However, over a relatively short time span, humans have disrupted this natural cycle of illumination with the introduction and now widespread proliferation of artificial light at night (ALAN). Growing research in a broad range of fields, such as ecology, the environment, human health, public safety, economy, and society, increasingly shows that ALAN is taking a profound toll on our world. Much of our current understanding of light pollution comes from datasets generated by remote sensing, primarily from two missions, the Operational Linescan System (OLS) instrument of the now-declassified Defense Meteorological Satellite Program (DMSP) of the U.S. Department of Defense and its follow-on platform, the Day-Night Band (DNB) of the Visible Infrared Imaging Radiometer Suite (VIIRS) instrument on board the Suomi National Polar-Orbiting Partnership satellite. Although they have both proved invaluable for ALAN research, sensing of nighttime lights was not the primary design objective for either the DMSP-OLS or VIIRS-DNB instruments; thus, they have some critical limitations. Being broadband sensors, both the DMSP-OLS and VIIRS-DNB instruments suffer from a lack of spectral information. Additionally, their spatial resolutions are too low for many ALAN research applications, though the VIIRS-DNB instrument is much improved over the DMSP-OLS in this regard, as well as in terms of dynamic range and quantization. Further, the very late local time of VIIRS-DNB observations potentially misses the true picture of ALAN. We reviewed both current literature and guiding advice from ALAN experts, aggregated from a diverse range of disciplines and Science Goals, to derive recommendations for a mission to expand knowledge of ALAN in areas that are not adequately addressed with currently existing orbital missions. We propose a stand-alone mission focused on understanding light pollution and its effects on our planet. Here we review the science cases and the subsequent mission recommendations for NITESat (Nighttime Imaging of Terrestrial Environments Satellite), a dedicated ALAN observing mission. [ABSTRACT FROM AUTHOR]