A linear systems approach to protect the night sky: implications for current and future regulations.

It was an August afternoon in 2003 when the lights went out on Broadway, and for that matter, throughout most of the Northeast, Midwest, and Ontario—a power blackout left 50 million customers in the dark overnight. Despite complaints about the inconveniences, the stranded commuters, and the food spoilage in restaurants and markets, many city dwellers were also awed; as evening came on, they gazed upward, and between the dark skyscrapers they could see something amazing—the starry night sky. The New York Times reported spontaneous stargazing gatherings in the usually electrified cities of the Northeast.

<p>Artificial light at night (ALAN) has become a major concern in recent years due to its impact on the health of human beings and the ecosystems. As a result, there is a surge of light pollution research not only on night sky brightness, but also on assessments of impacts on both ecology and society.</p><p>We have set up an interdisciplinary project in Hungary since September 2017, to not only study the impacts of change in lighting technology on patterns of ALAN (with emphasis on the areas within and around national parks in Hungary), but also facilitate national and international cooperations in light pollution research. We refer to this project as Living Environmental Laboratory for Lighting (LELL). Specifically, the project covers the following areas:</p><p><strong>1. Development of new techniques for night sky radiometry and spectrometry</strong><br>We are developing techniques for night sky multispectral measurements using commercially available cameras with interchangeable lens, calibrated by high sensitivity spectroradiometer, in order to quantify night sky condition and identify sources of artificial light at high resolution not achieveable by systems based on panchromatic sensors or fisheye lenses. In addition, we will compare the results from our ground-based measurements with satellite-based observations.</p><p><strong>2. Modeling of night sky patterns in national parks of Hungary</strong><br>We have developed a Monte-Carlo method of modeling light pollution, which can also be used for investigating effects of aerosols and clouds on the propagation of artificial light.</p><p><strong>3. Impact assessments of ALAN through measurements</strong><br>The public lighting was remodeled to LED-based systems in two areas close to national parks, one of which in the Zselic region in Southwestern Hungary, and another in Bükk in Northern Hungary. Using the techniques above, we are monitoring the change in night sky brightness and color, as well as the impact on flora and fauna.</p><p><strong>4. Recommendations on future assessments and mitigations of</strong> <strong>light pollution</strong><br>With our experience gain within the duration of this project, we will inform the light pollution research community of standardizing methodologies for monitoring light pollution, as well as giving recommendations for managing public lighting assets to reduce the impacts of light pollution.</p><p><br><strong>Acknowledgement</strong><br>This project is supported by the European Union and co-financed by the<br>European Social Fund (Grant no. EFOP–3.6.2–16–201–00014: Development of<br>international research environment for light pollution studies)</p>

The light pollution levels experienced at any given site generally depend on a wide number of artificial light sources distributed throughout the surrounding territory. Since photons can travel long distances before being scattered by the atmosphere, any effective proposal for reducing local light pollution levels needs an accurate assessment of the relative weight of all intervening light sources, including those located tens or even hundreds of km away. In this paper we describe several ways of quantifying and visualizing these relative weights. Particular emphasis is made on the aggregate contribution of the municipalities, which are -in many regions of the world- the administrative bodies primarily responsible for the planning and maintenance of public outdoor lighting systems

This article presents a methodology to estimate the volume of carbon dioxide CO2, which has not been emitted into the atmosphere by the use of luminaires with a switchable energy system that have been installed in the public lighting system in 2019 in the city of Cuenca - Ecuador. It shows the important results of energy saving in public lighting, the reduction of CO2 emissions and light pollution, because there is no evaluation to see the effectiveness of the use of these systems in Cuenca. To achieve this purpose, the number of luminaires with switchable systems installed in 2019 was established and their level of power reduction was verified in the laboratory, the amount of energy saved, the reduction of light pollution and the volume of CO2 that it has stopped emitting into the atmosphere. Finally, as a consequence of the study, it is established that the use of luminaires with a power variation system is considered a valid technology that contributes to energy savings that reduces CO2 emissions and reduces light pollution without significantly affecting the provision of lighting.KeywordsLightingEnergy savingLighting pollutionEmissionLuminaires

Bright night lights have become a symbol of development and prosperity in the modern world. But have you ever wondered how artificial light at night (ALAN) may be affecting living beings in our cities, and how it may be affecting us? As artificial illumination is transforming nocturnal environments around the world, light pollution associated with its use is becoming a topic of increasing interest in the scientific and public communities. Light pollution disrupts natural light regimes in many regions of the world, raising concerns about ecological and health impacts of this novel anthropogenic pressure. Most obviously, ALAN can influence night‐active animals in urban and suburban areas, and most research in this growing field focuses on terrestrial organisms such as bats, birds, and insects. Effects on aquatic ecosystems are much less known. In particular, aquatic primary producers, such as microalgae, cyanobacteria, and plants, have rarely been studied despite their critical positioning in the base of aquatic food webs and the fundamental role that light plays in their ecology. For primary producers, light is a key source of both energy and environmental information; it influences their growth, production, and community structure. ALAN has therefore a large potential to influence their communities and induce bottom‐up changes to aquatic ecosystems and ecosystem functions.

21 - Lighting

Light pollution has significantly increased in recent years, in concert with urban sprawl. Light pollution consequences for nocturnal wildlife, human health, and energy consumption are numerous but are poorly tackled in urban policies. The regulation and mitigation of light pollution is possible, but requires an important shift in the lighting paradigm, including in public lighting often managed by local authorities. One of the main sources of reticence of local authorities to regulate light pollution is the potential rejection by citizens of lighting changes. In this article, we investigate citizens’ willingness to accept the transition to more sustainable lighting regimes. We use a discrete choice experiment in a large French metropolis to measure the relative weight of different characteristics of public lighting – light intensity, light extinction, light colour – in respondents’ decisions. We show that respondents are globally open to public lighting shifts, but their preferences in terms of the changes are highly heterogeneous. By incorporating socioeconomic variables of respondents into our econometric models, we characterise the main profiles of preferences regarding lighting changes. This provides practical information to urban and environmental planners allowing them to match the municipalities where the need for light pollution control is a priority with those where measures seem socially acceptable by citizens.

ABSTRACTThe broad implementation of light emitting diode (LED) light sources in public lighting has become a revolution in recent years. Their low power consumption and good performance (extremely low onset time, long lifetime, high efficacy) make LEDs an optimal solution in most outdoor applications. In addition, the white light emitted by the vast majority of LEDs used in public lighting and their good color rendering improve well-being, comfort, and safety in cities, especially in commercial zones and urban centers. However, regulations on light pollution that have been developed in some countries in parallel to the introduction of LED lighting impose strong constraints to white light emission, which is present due to the higher Rayleigh scattering of short wavelengths. These regulations request filtering blue wavelengths in some protected areas and thus limit the projects to high- or low-pressure sodium sources or amber LEDs. In this work, the pros and cons of white and amber LED lighting in rural areas are analyzed and compared through simulations made on a typical rural lighting situation and considerations based on efficiency, visual performance, nonvisual effects, and light pollution. The most important conclusion is that Rayleigh scattering seems to prevail in the current considerations on light pollution, whereas other important aspects affecting safety and sustainability are are not considered. Accurate designs can decrease light pollution without constraints against white LEDs. The objective of this work is to provide evidence leading to consider light pollution from a more general perspective in the benefit of humans and the environment.

In recent years, excessive or improper application of artificial lighting has had resulted serious environmental consequences, scientifically known as Light Pollution. The night sky and ocean close to transportation terminals are illuminated by a variety of artificial lights, including high-mast lights, navigation lights, security/emergency lights, crane and equipment lighting, LED floodlights, and dock lighting, in addition to the primary natural light sources of sunlight, moonlight, stars, and bioluminescent light. These high-intensity lights have been shimmering along the coastlines, creating a pathway for light pollution and its effects. Research on optical oceanography and ALAN (Artificial Light at Night) impact is expanding globally. However, there is a great dearth of research regarding light pollution related to seaport terminals in Sri Lanka as ALAN is relatively a new area of analysis. The aim of this narrative review paper is to address the question, “what are the ecological impacts of artificial lighting from seaports on marine life” and to raise policymakers’ awareness on potential threats marine ecology. Scopus, Google Scholar databases and IMO publications were used for the scientific literature search. Terminal lighting is crucial factor in a seaport for safety, security, and efficiency of movement of people and commodities during around-the-clock operations and the vertical and horizontal light in buoys and beacons are crucial for hazard avoidance in ships. Standards of IMO and International Commission on Illumination (CIE), minimum illumination levels, color temperature levels, and Color Rendering Index are maintained at sea ports for safer navigation and operations. Terminal light emissions beyond shorelines, disrupt delicate underwater ecosystems in pelagic zones and coastal areas. According to literature, around 2 million km² of the world's ocean at a depth of 1 m are affected by light pollution. ALAN impacts include changes in predator- prey interaction patterns of fish, coral spawning, zooplankton diel vertical migration (DVM), and seabird / sea turtle navigation. LED lights’ white illumination, adversely affect the recruitment and colonization of marine epifaunal communities like sessile and mobile invertebrate species. Regulations mandate light intensities, luminous intensity, and spectral power distribution units, focusing on human vision, but similar visual metrics should be developed considering the marine and nocturnal animals for more sustainable and environmentally friendly practice. The scientists have developed the Light Pollution Index (LPI) to measure the ALAN impact at night sky. Additionally, strategies like WWF earth hour, green space management and light flow control also used to mitigate the ALAN impacts in infrastructure development. Effective mitigation strategies further include proper placement/direction of vertical beam spread, removing excess lights, reduce uplighting & residual effects, installing timers or dimmers, and using shielded lighting fixtures. Additionally, raise awareness on light pollution, as the DarkSky International, have shown measurable impacts on urban light levels. Inarguably the night sky and marine ecosystems are at threat due to ALAN impact caused by seaports and nearby urban structures. There’s a growing need to include the effects of light pollution analysis in port master plans. This study emphasizes that careful analysis and preventive strategies exist to constrain and to reduce the ALAN impact of seaports while ensuring safe and efficient operation.

Natural variation of the colour and spectrum of the night sky observed at a potential european reference site for dark skies

Contributions of artificial lighting sources on light pollution in Hong Kong measured through a night sky brightness monitoring network

Building footprint (BFP) extraction focuses on the precise pixel-wise segmentation of buildings from aerial photographs such as satellite images. BFP extraction is an essential task in remote sensing and represents the foundation for many higher-level analysis tasks, such as disaster management, monitoring of city development, etc. Building footprint extraction is challenging because buildings can have different sizes, shapes, and appearances both in the same region and in different regions of the world. In addition, effects, such as occlusions, shadows, and bad lighting, have to also be considered and compensated. A rich body of work for BFP extraction has been presented in the literature, and promising research results have been reported on benchmarking datasets. Despite the comprehensive work performed, it is still unclear how robust and generalizable state-of-the-art methods are to different regions, cities, settlement structures, and densities. The purpose of this study is to close this gap by investigating questions on the practical applicability of BFP extraction. In particular, we evaluate the robustness and generalizability of state-of-the-art methods as well as their transfer learning capabilities. Therefore, we investigate in detail two of the most popular deep learning architectures for BFP extraction (i.e., SegNet, an encoder–decoder-based architecture and Mask R-CNN, an object detection architecture) and evaluate them with respect to different aspects on a proprietary high-resolution satellite image dataset as well as on publicly available datasets. Results show that both networks generalize well to new data, new cities, and across cities from different continents. They both benefit from increased training data, especially when this data is from the same distribution (data source) or of comparable resolution. Transfer learning from a data source with different recording parameters is not always beneficial.

The light-emitting-diode (LED) revolution has drastically decreased the quality of the United States’ night sky. LEDs are brighter than the sodium doublet lighting fixtures they are replacing, causing an increase in light pollution. Emerging technology promises to replace high-color-temperature LED lighting with lower-color-temperature lighting that reduces light pollution. High-color-temperature, or “cool-lighting” causes unnecessary amounts of light pollution that decreases humanity's connection with the cosmos through stargazing. Policy implementations can increase public awareness of how LEDs affect light pollution through research grants and tax incentive structures. The federal government can directly decrease the United States’ luminous footprint by funding research on warm-light LED development , regulating LED lighting on federal projects to only use low-color-temperature LED fixtures and offering incentives to communities to reduce their light pollution through the tax code.

The view of the night sky from most of the populated regions of Earth is now seriously compromised by light pollution. An entire generation of citizens is now growing up without ever having the opportunity to gaze upon the magnificent night sky from a dark location. Much of modern astronomy involves study of faint objects, often with brightnesses similar to or fainter than the night sky. Astronomers are therefore extremely vulnerable to increases in sky brightness from light pollution. Despite their remote locations, the dark night skies over the major optical observatories are increasingly threatened by growth of artificial light at night.

Light pollution is recognized as a global issue that, like other forms of anthropogenic pollution, has a significant impact on ecosystems and adverse effects on living organisms. Plentiful evidence suggests that it has been increasing at an unprecedented rate at all spatial scales. Chile—which, thanks to its unique environmental conditions, has become one of the most prominent astronomical hubs of the world—seems to be no exception. In this paper we present the results of the first observing campaign aimed at quantifying the effects of artificial lights at night on the brightness and colors of the Chilean sky. Through the analysis of photometrically calibrated all-sky images captured at four representative sites with an increasing degree of anthropization, and the comparison with state-of-the-art numerical models, we show that significant levels of light pollution have already altered the appearance of the natural sky even in remote areas. Our observations reveal that the light pollution level recorded in a small town of the Coquimbo Region is comparable with that of Flagstaff, Arizona, a ten times larger Dark Sky city, and that a mid-size urban area that is a gateway to the Atacama Desert displays photometric indicators of night sky quality that are typical of the most densely populated regions of Europe. Our results suggest that there is still much to be done in Chile to keep light pollution under control and thus preserve the darkness of its night sky—a natural and cultural heritage that it is our responsibility to protect.