Global Approaches to Reduce Light Pollution from Media Architecture and Non-Static, Self-Luminous LED Displays for Mixed-Use Urban Developments

Abstract

Urban environments have become significantly brighter and more illuminated, and cities now consider media architecture and non-static, self-luminous LED displays an essential element of their strategy to attract residents, visitors, and tourists in the hours after dark. Unfortunately, most often, they are not designed with care, consideration, and awareness, nor do they support the visual wellbeing and circadian rhythms of humans. They also increase light pollution which has an adverse effect on the environment. The aim of this study was to estimate the scale of the negative impact of 28 non-static, self-luminous LED shop window displays within a real-life city context along the main shopping street Banhofstrasse in Zurich, Switzerland. An experimental field measurement survey investigation was performed to identify visual luminance with commonly available tools such as a luminance meter and a digital reflex camera for luminance photography. Moreover, the most important global approaches to reduce light pollution were evaluated in the form of existing guidelines, technical standards, and laws, all of which should be considered when specifying illuminated digital advertisements. A literature review and survey results both confirmed the extent of the problem and highlighted, too, the need to better measure, apply, and manage this new technology. The authors' proposal for improvements involve practical recommendations for the design and implementation of future projects which can positively guide and direct this growing trend.

Full text

sustainability
Article
Global Approaches to Reduce Light Pollution from
Media Architecture and Non-Static, Self-Luminous
LED Displays for Mixed-Use Urban Developments
Karolina M. Zielinska-Dabkowska 1, * and Kyra Xavia 2
1GUT Light Lab, Faculty of Architecture, Gdansk University of Technology (GUT), 80-233 Gdansk, Poland
2International Dark-Sky Association, Tucson, AZ 85719, USA; kyra.xavia@darksky.org
*Correspondence: k.zielinska-dabkowska@pg.edu.pl; Tel.: +48-583-472-315
Received: 1 April 2019; Accepted: 18 June 2019; Published: 22 June 2019


Abstract:
Urban environments have become significantly brighter and more illuminated, and cities
now consider media architecture and non-static, self-luminous LED displays an essential element
of their strategy to attract residents, visitors, and tourists in the hours after dark. Unfortunately,
most often, they are not designed with care, consideration, and awareness, nor do they support
the visual wellbeing and circadian rhythms of humans. They also increase light pollution which
has an adverse effect on the environment. The aim of this study was to estimate the scale of the
negative impact of 28 non-static, self-luminous LED shop window displays within a real-life city
context along the main shopping street Banhofstrasse in Zurich, Switzerland. An experimental field
measurement survey investigation was performed to identify visual luminance with commonly
available tools such as a luminance meter and a digital reflex camera for luminance photography.
Moreover, the most important global approaches to reduce light pollution were evaluated in the
form of existing guidelines, technical standards, and laws, all of which should be considered when
specifying illuminated digital advertisements. A literature review and survey results both confirmed
the extent of the problem and highlighted, too, the need to better measure, apply, and manage
this new technology. The authors’ proposal for improvements involve practical recommendations
for the design and implementation of future projects which can positively guide and direct this
growing trend.
Keywords:
light pollution; media architecture; media facades; non-static LED displays; LED screens;
illuminated digital advertisement; video displays; self-luminous surfaces
1. Introduction
In recent decades, urban environments have become significantly brighter and more illuminated
(Figure 1), and cities now consider lighting an essential element of their strategy to attract residents,
visitors, and tourists in the hours after dark [
1
,
2
]. Additionally, urban planners have realized that
dividing a city into separate districts for specific purposes, such as residential, commercial, cultural,
institutional or environmental land use, no longer works from a functional perspective for city
inhabitants. After business hours, one can observe that in commercial and institutional quarters,
these parts of a city can become dark and unwelcoming places with an absence of people in the
streets. To overcome this problem and inject more life into certain city areas, a new trend has emerged.
Mixed-use development integrates retail (i.e., shops and restaurants) enterprises which are often
located on the ground floor, with commercial and residential properties on the floors above. While
this change increases economic prosperity and socializing in the night hours to create livable cities [
3
],
increased light pollution can negatively impact the area and reduce the quality of life for residents [
4
,
5
].
Sustainability 2019,11, 3446; doi:10.3390/su11123446 www.mdpi.com/journal/sustainability

Sustainability 2019,11, 3446 2 of 33
Sustainability 2019, 11, x FOR PEER REVIEW 2 of 34
Figure 1. Guangzhou, China: cities now consider creative lighting an essential element of their
strategy to attract residents, visitors, and tourists in the hours after dark. Source: Signify’s figure.
In 2009, an approved European 2020 Strategy for climate change and energy recommended the
following: minimizing greenhouse gas emissions to 20% lower than 1990 levels, the use of 20% of
energy coming from renewable sources, and a 20% increase in energy efficiency that involves the
employment of effective technologies such as LEDs [6].
As LED lighting is considered more energy efficient, adaptable, and cheaper to operate than
older light sources, it is already in use in street lighting retrofit projects [7–9], historical urban settings
[10], facade illumination [11,12], landscape lighting [13], in trials for a smart city [14], and as animated
LED video advertisement displays in different forms applied to buildings [15]. According to market
estimates and forecasts, the future trend of global LED video display technology will grow around
35% over the next decade, reaching approximately $73 billion by 2025 [16]. Certainly, when applied
and controlled properly with suitable relevance to the building’s architecture and/or the urban realm
in which they are introduced, media architecture and non-static, self-luminous LED displays can
positively add to the nighttime image of a city by creating a visually stimulating atmosphere [17]. But
adequate guidance is necessary and one should acknowledge not all cities and towns need visual
clutter. Times Square, Piccadilly Circus, and Shinjuku each have their own historical relationship
with bold advertisements that create a one-of-a-kind place of identity that attracts tourists, but it is
worth noting that these areas do not contain residential dwellings (city accommodations should
provide adequate darkness at night for the health and wellbeing of its inhabitants).
Researchers and practitioners within the field have provided some insights into the body of
knowledge of these new urban elements, from technology and prototyping [18], policy and design
issues [19,20], social interaction [21], displayed context [22], to design challenges [23], aesthetics [24],
and more. Alas, there is still very little research on the environmental and health impacts of outdoor
media architecture [25]. Therefore, while research exists to assist our understanding of this trend and
its numerous applications, more studies are required to help better apply and manage the use of this
recently developed lighting technology.
This is pertinent because the majority of non-static, self-luminous LED displays today are
excessively bright and without any controls in place [26,27]. This diminishes the nighttime landscape
here on Earth, whilst also substantially adding to the sky glow above cities. Light pollution, also
known as obstructive light, prevents astronomical observations and disconnects humanity from the
night sky as well [28]. In particular, LEDs emit excessive luminance and generate unwanted glare
[29]. Also, their high-intensity light restricts the pupil in the human eye, thus dark adaptation is
prevented, making it impossible to detect all but the brightest stars in the sky (while the sky may
appear almost black, the fine detail of the night sky becomes invisible) [30,31].
Figure 1.
Guangzhou, China: cities now consider creative lighting an essential element of their strategy
to attract residents, visitors, and tourists in the hours after dark. Source: Signify’s figure.
In 2009, an approved European 2020 Strategy for climate change and energy recommended the
following: minimizing greenhouse gas emissions to 20% lower than 1990 levels, the use of 20% of
energy coming from renewable sources, and a 20% increase in energy efficiency that involves the
employment of effective technologies such as LEDs [6].
As LED lighting is considered more energy efficient, adaptable, and cheaper to operate than older
light sources, it is already in use in street lighting retrofit projects [
7
–
9
], historical urban settings [
10
],
facade illumination [
11
,
12
], landscape lighting [
13
], in trials for a smart city [
14
], and as animated
LED video advertisement displays in different forms applied to buildings [
15
]. According to market
estimates and forecasts, the future trend of global LED video display technology will grow around
35% over the next decade, reaching approximately $73 billion by 2025 [
16
]. Certainly, when applied
and controlled properly with suitable relevance to the building’s architecture and/or the urban realm
in which they are introduced, media architecture and non-static, self-luminous LED displays can
positively add to the nighttime image of a city by creating a visually stimulating atmosphere [
17
].
But adequate guidance is necessary and one should acknowledge not all cities and towns need visual
clutter. Times Square, Piccadilly Circus, and Shinjuku each have their own historical relationship with
bold advertisements that create a one-of-a-kind place of identity that attracts tourists, but it is worth
noting that these areas do not contain residential dwellings (city accommodations should provide
adequate darkness at night for the health and wellbeing of its inhabitants).
Researchers and practitioners within the field have provided some insights into the body of
knowledge of these new urban elements, from technology and prototyping [
18
], policy and design
issues [
19
,
20
], social interaction [
21
], displayed context [
22
], to design challenges [
23
], aesthetics [
24
],
and more. Alas, there is still very little research on the environmental and health impacts of outdoor
media architecture [
25
]. Therefore, while research exists to assist our understanding of this trend and
its numerous applications, more studies are required to help better apply and manage the use of this
recently developed lighting technology.
This is pertinent because the majority of non-static, self-luminous LED displays today are
excessively bright and without any controls in place [
26
,
27
]. This diminishes the nighttime landscape
here on Earth, whilst also substantially adding to the sky glow above cities. Light pollution, also
known as obstructive light, prevents astronomical observations and disconnects humanity from the
night sky as well [
28
]. In particular, LEDs emit excessive luminance and generate unwanted glare [
29
].
Also, their high-intensity light restricts the pupil in the human eye, thus dark adaptation is prevented,
making it impossible to detect all but the brightest stars in the sky (while the sky may appear almost
black, the fine detail of the night sky becomes invisible) [30,31].

Sustainability 2019,11, 3446 3 of 33
When such displays are visually too bright compared to the surroundings, they also negatively
impact the movement of pedestrians and drivers [
32
]. Additionally, light trespass may enter the
interior of residential properties at night, causing distress and insomnia [33].
As there are no worldwide established standards and recommendations regarding how to correctly
design, apply, and verify the impact of media architecture and colorful, non-static, self-luminous LED
displays in an urban context [
34
], research in this field seems to be novel and significant. Furthermore,
immediate action is required by the international authority on light and illumination—the International
Commission on Illumination (CIE)—to provide guidelines to reduce the impact of artificial light at
night (radiating from these lighting features) on all end users (humans, flora, and fauna), and to
encourage respect for the nighttime urban landscape, while at the same time, supporting business and
event advertising, and ensuring easy navigation and wayfinding in cities.
Ideally, there ought to be a balance between these conflicting developments. But how can
improvements be made when the approved research methodology islimited and measuring instruments
to evaluate the luminance (how bright an illuminated surface will appear) of non-static, self-luminous
LED displays are unavailable? Only recently in 2018 did the CIE establish a Technical Committee (4–58:
Obtrusive Light from Colourful and Dynamic Lighting and its Limitation) [
35
] to provide guidelines
for the implementation and usage of colorful and dynamic lighting in outdoor applications. It aims to
limit obtrusive light to allow astronomical observations, support human health, and to protect the
nighttime environment. The CIE is also now looking into the development of metrics and suitable
methods that will help to limit or prevent obtrusive light from such lighting systems.
The first aim of this research study is to raise awareness about global light pollution in mixed-use
developments in large cities from media architecture and non-static LED displays, and to provide an
in-depth account of existing global light pollution laws. With such displays becoming more common
in urban environments, this material is not only relevant and necessary, it will help shape the future
landscape and nightscape of our cities and towns.
Moreover, based on the presented case study of Zurich’s Banhofstrasse shopping street, which
has experienced an unprecedented 43 fold increase in the installation of video LED displays since 2015,
suggestions are proposed on how to improve the existing situation with guidance that contributes new
knowledge to the field. The authors also highlight the possible difficulties involved with measuring
non-static, self-luminous LED displays with commonly approved and available devices such as a
luminance meter and digital reflex camera for luminance photography.
The second aim of this research study is to establish effective design principles that contribute to
the development of environmentally sustainable regulations for the design and application of non-static,
self-luminous LED advertising. It is not only lighting designers and illuminating engineers who will
gain from this research; those involved in the design, planning, and approval process will also benefit.
This includes light artists, architects, urban planners, landscape designers, sustainability consultants,
biologists, ecologists, and planning officers (representatives of local planning authorities). Last but
not least, this research will help improve the enjoyment of cities after dark. This includes improved
walkability, navigation and wayfinding in urban spaces, and most importantly, the facilitation of
conditions that better support quality sleep for residents, tourists, and visitors alike.
This paper is organized into eight sections. Section 1: demonstrates how the research fits within a
larger field of study and highlights why it is important. Section 2: provides definitions and an extensive
background study of global approaches to reduce light pollution. Section 3: defines the research
hypothesis. Section 4: describes traditional methodologies and new methods and protocols to evaluate
the luminance of non-static, self-luminous LED displays. Section 5: provides a precise description
and summary of the experimental results. Section 6: discusses the findings and their implications,
and explains how they can be interpreted via their perspective of the working hypotheses. Section 7:
provides the study’s limitations. Finally, Section 8was added to provide a synthesis of the key points
and recommends new areas for future research, as Sections 7and 8of the study are long and complex.

Sustainability 2019,11, 3446 4 of 33
2. Background Research
An extensive background study was undertaken for a period of six months. This involved
investigating the global approaches to reduce light pollution from media architecture and animated
LED displays. Our research consisted of a thorough review of published lighting standards, guidance
and policies, books, scientific research papers, reports, and realized case studies, and also involved
personal interviews with tram drivers and passersby within in the area researched.
2.1. The Importance of Correct Definitions
When a new field emerges, as in the case of media architecture [
36
], and when no clear
interchangeable definitions are established by professionals that can be commonly adopted by
the general public, one ends up with different interpretations and meanings [
37
]. A definition permits
mutual understanding of a topic when a particular subject is discussed and debated. In the context of
this paper, in order to fully absorb and understand the content, definitions for the following four terms
have been provided: (1) media architecture; (2) non-static LED advertising; (3) visual light clutter; and
lastly, (4) light pollution (Table 1).
As more research and knowledge relating to the field of lighting have become available, the
definition of media architecture [38] requires an update.
Table 1. An overview of new definitions. Source: authors’ elaboration.
Definition Proposed Description
Media Architecture
Media architecture is a new emerging field within exterior illumination, where
dynamic graphics, text, images, and spatial movement are displayed on elements of
the built environment, properly integrated within architectural structures and/or
buildings within public spaces. Modern digital technologies allow for adaptation
and interaction with users. The main function of media architecture is to
“communicate specific information” in an active, dynamic, and interactive form via
high-quality visual and artistic content. Media facades and digital outdoor media
displays that emit light are a vital component of media architecture and the
digitalization of cities, forming part of the original and intellectual enrichment of
the urban environment with cultural, social, and economic implications for the
immediate surroundings. Such installations are usually permanent in nature, but
can have variable, temporary content. Well-designed media architecture should not
only enhance the environment, it should also be biologically and ecologically
responsible, minimizing its impact on the nighttime landscape, and the health and
well-being of human residents, wildlife, and/or flora and fauna.
Non-Static LED
Advertising
Non-static LED advertising can be defined as a means of promoting just about
anything in a publicly or privately owned space. It can also be used commercially
for marketing purposes (light art installations). The systems use LEDs and feature
different resolutions, colors, luminous intensities, and lighting controls. They can
be installed on a temporary or permanent basis, and content can be dynamic or
static, in low or high resolution, and in the form of text, images or video sequences.
Due to the technological advancements in the development of the brightness of
LEDs, such display systems can also be used outdoors during daylight hours.
There are different types of digital advertising platforms: signs, logos, lettering,
shop windows, screens or media facades [39].
Visual Light Clutter
Visual light clutter in the urban environment at night (Figure 3) is defined by the
authors as the state in which too many items lead to a degradation of the
performance of a visual task at night. This occurs when the human eye cannot rest,
as it is constantly scanning, moving, and absorbing information from an
environment with an excess of light sources, coupled with sudden changes in
luminance levels and contrast. All of these factors can cause an extreme sense of
chaos and disharmony in the urban realm.
Light Pollution
“. . . every form of artificial light in the wrong place at the wrong time which
creates sky glow, glare, nuisance, and other relevant causes of environmental
degradation including some properties of artificial light which emit
non-environmentally friendly or inappropriate light” [
40
]. Typically, light pollution
consists of four forms: sky glow, glare, over-lighting, and light trespass.

Sustainability 2019,11, 3446 5 of 33
Today, it is also important to differentiate between media architecture and commercial LED video
advertising, which is often inadequately integrated within a building envelope and works as an add-on.
Keep in mind that the location of media architecture is usually decided by the architect of a particular
building and other consultants in order to eliminate any potential safety conflicts in critical traffic
zones, for example, intersections where the increased attention of pedestrians, cyclists, and drivers of
cars, buses, trams, and other vehicles is required. To reduce the negative impact on the environment
and the health and wellbeing of residents, appropriate design and controls are necessary.
Additionally, high-quality visual and artistic content should be provided and applied by
professional designers who also define and set different technical parameters. This may include
the appropriate pace (number of frames per minute) to allow enough time for identification and
absorption of the communicated message. While media architecture can become a well-known
landmark for both tourists and locals alike—it is important to stress that although media architecture
can incorporate elements of digital outdoor advertising, LED outdoor advertising is not media
architecture per se (Figure 2). Both media architecture and non-static LED display advertising can add
to visual light clutter if it is poorly designed (Figure 3).
Interestingly, with time and exposure, some people become “immune” to advertising information
and overload, and as a consequence, barely notice advertisements. This questions the overall impact
and substantial cost of such marketing modes employed in the late hours of the night.
Sustainability 2019, 11, x FOR PEER REVIEW 5 of 34
Today, it is also important to differentiate between media architecture and commercial LED
video advertising, which is often inadequately integrated within a building envelope and works as
an add-on. Keep in mind that the location of media architecture is usually decided by the architect of
a particular building and other consultants in order to eliminate any potential safety conflicts in
critical traffic zones, for example, intersections where the increased attention of pedestrians, cyclists,
and drivers of cars, buses, trams, and other vehicles is required. To reduce the negative impact on the
environment and the health and wellbeing of residents, appropriate design and controls are
necessary.
Additionally, high-quality visual and artistic content should be provided and applied by
professional designers who also define and set different technical parameters. This may include the
appropriate pace (number of frames per minute) to allow enough time for identification and
absorption of the communicated message. While media architecture can become a well-known
landmark for both tourists and locals alike—it is important to stress that although media architecture
can incorporate elements of digital outdoor advertising, LED outdoor advertising is not media
architecture per se (Figure 2). Both media architecture and non-static LED display advertising can
add to visual light clutter if it is poorly designed (Figure 3).
Figure 2. Times Square, New York, US: LED outdoor advertising is not media architecture per se.
Source: Andre Benz/Unsplash’s figure.
Figure 3. Visual light clutter of Shinjuku—one of Tokyo’s business districts at night. Source: Perati
Komson/Shutterstock’s figure
Figure 2.
Times Square, New York, US: LED outdoor advertising is not media architecture per se.
Source: Andre Benz/Unsplash’s figure.
Sustainability 2019, 11, x FOR PEER REVIEW 5 of 34
Today, it is also important to differentiate between media architecture and commercial LED
video advertising, which is often inadequately integrated within a building envelope and works as
an add-on. Keep in mind that the location of media architecture is usually decided by the architect of
a particular building and other consultants in order to eliminate any potential safety conflicts in
critical traffic zones, for example, intersections where the increased attention of pedestrians, cyclists,
and drivers of cars, buses, trams, and other vehicles is required. To reduce the negative impact on the
environment and the health and wellbeing of residents, appropriate design and controls are
necessary.
Additionally, high-quality visual and artistic content should be provided and applied by
professional designers who also define and set different technical parameters. This may include the
appropriate pace (number of frames per minute) to allow enough time for identification and
absorption of the communicated message. While media architecture can become a well-known
landmark for both tourists and locals alike—it is important to stress that although media architecture
can incorporate elements of digital outdoor advertising, LED outdoor advertising is not media
architecture per se (Figure 2). Both media architecture and non-static LED display advertising can
add to visual light clutter if it is poorly designed (Figure 3).
Figure 2. Times Square, New York, US: LED outdoor advertising is not media architecture per se.
Source: Andre Benz/Unsplash’s figure.
Figure 3. Visual light clutter of Shinjuku—one of Tokyo’s business districts at night. Source: Perati
Komson/Shutterstock’s figure
Figure 3.
Visual light clutter of Shinjuku—one of Tokyo’s business districts at night. Source: Perati
Komson/Shutterstock’s figure

Sustainability 2019,11, 3446 6 of 33
2.2. Existing Light Pollution Laws, Related Lighting Standards and Guidlines
Recent years have seen issues pertaining to light pollution being acknowledged in both scientific
studies [
41
] and legal consciousness [
42
]. Even though light pollution presents a major challenge for
international lawmakers due to the diversity of its scope, the United Nations Educational, Scientific, and
Cultural Organization (UNESCO) and the International Astronomical Union (IAU) both introduced
the autonomous right for every human to transboundary dark-sky landscapes and nocturnal areas.
Based on their own legal frameworks, they enforce the responsibility to guarantee that actions do not
cause excessive harm to the nighttime environment [40].
To achieve light pollution control at regional and international levels, it is essential to circulate
information about it and provide good practice principles for responsible external illumination.
The light pollution frameworks that exist in many countries, such as France, Italy, Korea, Slovenia,
Spain, and the US, have emerged from multidisciplinary fields of lighting and varied approaches to
environmental law. Light pollution has possible negative consequences which breach domestic and
international environmental legislation, such as “the right to light pollution control development, the
right to a healthful nocturnal environment, mankind’s right to a common dark-sky heritage, the right
to know the harm caused by light pollution, the duty to carry out light pollution impact assessment,
and the duty to adopt effective domestic light pollution law (duty to enforce)” [40].
In 2007, the Slovenian light pollution law, Decree on Limit Values due to Light Pollution of the
Environment, was one of the first in Europe. It established specific guidelines for advertisement
lighting which limits the electric power of an advertisement surface (W/m
2
) as well as the average
value of the entire illuminated facade surface to 1 cd/m2[43].
In the UK, the Clean Neighbourhoods and Environment Act 2005, makes light nuisance subject to
criminal law. It relates to “artificial light emitted from premises so as to be prejudicial to health or a
nuisance”. This act allows residents to take autonomous action [44].
In the US, both the IDA and the Illuminating Engineering Society of North America (IES) have
developed a Model Lighting Ordinance (MLO) to address the need for consistent and stringent outdoor
lighting regulation [
45
]. The MLO outdoor lighting template is intended to support municipalities in
developing outdoor lighting standards that reduce glare, light trespass, and sky glow, and its dark-sky
protective approach includes the use of five lighting zones to classify land use with appropriate lighting
levels for each of the zones. Also, the US Green Building Council (USGBC) via the Leadership in Energy
and Environmental Design (LEED) introduced a green building rating system. Their Light Pollution
Reduction Credit encourages the reduction of light trespass and sky glow [
46
], but the main objective
of this system is to save energy with lighting installations. For internally illuminated exterior signage,
they limit the luminance range to no more than 200 cd/m
2
during nighttime hours and 2000 cd/m
2
during daytime hours [47].
In France in 2013, the Anti-Light Pollution and Energy Consumption Law was introduced by the
Ministry of Ecology, Sustainable Development, and Energy. According to this regulatory framework,
illuminated advertising signs must be turned offat night, between 01:00 and 06:00, except for at airports
and in urban areas with more than 800,000 inhabitants. Surface luminance, energy consumption, and
anti-glare devices for digital illuminated advertisements were also defined [48].
In 2012, the Korean Ministry of the Environment passed the Act on the Prevention of Light
Pollution Due to Artificial Lighting to reduce severe light pollution brought about by the rapid economic
development of the past few decades. This regulation introduced limits on the average luminance and
maximal vertical plane illuminance of flashing screen videos based on four environmental zones and
the time of application [49].
In Hong Kong, a voluntary initiative established by the Environment Bureau of the Government
of the Hong Kong Special Administrative Region called the Charter on External Lighting was put in
place. This scheme requires participatory businesses to switch offall external lighting for decoration,
promotion or advertising, as well as rooftop signs, from 23:00–07:00. So far, a few thousand companies
have participated in this initiative [
50
]. Sadly, this voluntary scheme only partially reduces light

Sustainability 2019,11, 3446 7 of 33
pollution and it will not be effective if the authorities cannot issue warnings or penalties for those who
breach the requirements.
The existing European standard EN12464-2:2014, called Light and Lighting—Lighting of Work
Places, Part 2: Outdoor Work Places, published by the CIE [
51
], created requirements to protect
the nighttime environment and control the obstructive light from exterior lighting installations on
flora, fauna, and humans. Unfortunately, it does not differentiate between screen and sign luminance
requirements based on their size (Table 2). This means misinterpretation of the allowed values can
occur. Also, the small sign allowance of 1000 cd/m
2
for the high district brightness environmental zone
E4 (town/city centers and commercial areas with a high level of nighttime activity) will have less of a
negative impact on light pollution and glare, compared to displays that take up the whole window of a
shop front on the ground floor, etc., or even an entire facade [
51
]. In the past, signage was much smaller
so its luminance could be higher without impacting the surroundings on a large scale. Over time,
however, this changed and there are now large media facades and LED displays that sometimes cover
an entire building, yet the recommended luminance values remained the same, without taking into
consideration the size of the display. There is also no differentiation in the above lighting standard
between static and non-static displays. Additionally, the proposed standard measurement methodology
cannot be applied to non-static, self-luminous LED displays, as the measuring tools cannot simply
record the values (see Section 4.1.1 for a detailed explanation).
Table 2. Maximum obstructive light permitted for exterior lighting installations. Source: [51].
Environmental
Zone
Light on Properties Luminaire Intensity
Upward
Light
Ratio
Luminance
Ev
(lx)
I
(cd)
RUL
(%)
Lb
(cd/m2)
Ls
(cd/m2)
Pre-Curfew Post-Curfew Pre-Curfew Post-Curfew Building Facade Sign
E1 2 0 2500 0 0 0 50
E2 5 1 7500 500 5 5 400
E3 10 2 10,000 1000 15 10 800
E4 25 5 25,000 2500 25 25 1000
E1 represents intrinsically dark areas, such as national parks or protected sites; E2 represents low district brightness
areas, such as industrial or residential rural areas; E3 represents medium district brightness areas, such as industrial
or residential suburbs; E4 represents high district brightness areas, such as town centres and commercial areas;
Ev is the maximum value of vertical illuminance on properties in lx; I is the light intensity of each source in the
potentially obtrusive direction in cd; RUL is the proportion of the flux of the luminaire(s) that is emitted above the
horizontal, when the luminaire(s) is (are) mounted in its (their) installed position and attitude, and given in %; Lb is
the maximum average luminance of the facade of a building in cd/m
2
; Ls is the maximum average luminance of
signs in cd/m2.
Another attempt to limit the negative effects of light pollution involved the CIE 150: 2017, the
updated document titled the Guide on the Limitation of the Effects of Obstructive Light from Outdoor
Lighting Installations [
52
]. It defines the basis for well-designed external illumination and introduces
five different environmental zones (E0–E4) based on their use and location, and different aspects of
lighting. The guidance establishes acceptable levels of sky glow, light trespass into windows from
a facade, and the permissible maximum average luminance of a facade. It also recommends that
facade lighting be switched offcompletely after 23:00 and remain offuntil 06:00. Unfortunately, the
problems mentioned in the European standard EN12464-2:2014 were not addressed and resolved in
this document either.
Also, the Institution of Lighting Professionals (ILP) from the UK created a Professional Lighting
Guide PLG 05, called the Brightness of Illuminated Advertisement [
53
], which provides clear guidance
on the maximum recommended luminance level of a sign. For the first time, the luminance of an
advertisement display has been introduced in relation to its size (up to 10 and over 10 m
2
) for five specific
environmental zones. The suggested luminance levels are higher compared to the ANSI/IES RP-39-19
and IDA Guidance recommendations. Also, the proposed standard measurement methodology cannot

Sustainability 2019,11, 3446 8 of 33
be applied to non-static, self-luminous LED displays, as the measuring tools cannot simply record the
values (see Section 4.1.1 for a detailed explanation).
The recently published IES standard ANSI/IES RP-39-19, Recommended Practice: Off-Roadway
Sign Luminance [
54
], contains restrictions on maximum sign luminance to limit the negative impacts
of glare, light trespass, sky glow, animal attraction as well as driver distraction. These requirements are
only for the lighting of signs that are not regulated by a federal, state, provincial, or local jurisdiction,
and includes on-premise and off-premise, internally and externally illuminated, and electronic signs.
For the first time, luminance differentiation has been introduced for daytime and nighttime (Table 3).
The sign luminance levels are between 2 to 10 times lower for all environmental zones than the
recommended values by CIE. This is an American National standard, thus, it is only applicable in the US.
Still, in spite of any progress made, there is an issue with the measurement methodology as it
requires that: “All measurements shall be taken of the sign surface at its maximum level of illuminance”.
Although subsequent guidance instructs that: “The field of view of the meter used, shall be fully
covered by the white or lightest-colored surface of the sign”, this is impractical as it might be difficult
to achieve these criteria as the available measuring tools cannot record the values (see Section 4.1.1 for
a detailed explanation).
Table 3. Maximum sign luminance by lighting zone (cd/m2). Source: [54].
Lighting Zone Nighttime Daytime
LZ0 0 0
LZ1 20 3500
LZ2 40 3500
LZ3 80 3500
LZ4 160 3500
Also, the International Dark-Sky Association (IDA), a globally recognized leading authority that
combats light pollution, has played a vital role in protecting the nighttime environment as well as
preserving our heritage of dark skies via the promotion of best lighting practices and environmentally
responsible outdoor lighting. One of the latest additions to its work is the IDA’s Guidance for Electronic
Message Centers (EMCs) [55].
This document does not distinguish between on-premise signs and off-premise signs as do the IES
standards, nor between signs for advertising versus other uses. It provides minimum requirements and
a set of best management practices such as: monitoring, sensitive area setback, distraction limitations,
gradual brightness reductions, etc., in order to further decrease the negative impact and reduce the
environmental risks of illuminated signage. The recommended luminance levels for night are the same
as in ANSI/IES RP-39-19.
Although previous or existing national and international frameworks provide some general
guidelines on light pollution control from static advertisement signs, light pollution from media
architecture and LED non-static, self-luminous displays has only been partially addressed. This is an
important point because they differ substantially, see Table 4. There are a number of reasons for this:
•
The rapid development of solid-state lighting: LEDs and lighting control technology has meant
this field has just recently emerged, and although it has increased to an unprecedented scale, scant
research on its impact has been undertaken and made available;
•
While research is being undertaken in chronobiology and other related fields, wider awareness
is needed about the non-visual effects of artificial light on the circadian cycle and its negative
consequences on humans, flora, and fauna [
56
]. This crucial study needs to be acknowledged and
its outcomes integrated into lighting norms and regulations;
•
The mixed use of urban development sets a great challenge due to the conflicting interests of
businesses and residents;

Sustainability 2019,11, 3446 9 of 33
•
The changing light levels of existing LED video installations make it very difficult to accurately
measure their luminance output, and the equipment needed to do this effectively does not exist.
•Lastly, these standards and guidelines are not free of charge.
Table 4.
An overview of existing luminance requirements based on current lighting standards and
guidelines for mixed-use urban zones. Source: authors’ elaboration.
Lighting Standard/
Guidelines
Year
Published
Environmental
Zone Luminance at Night (cd/m2)Curfew
Times
EN12464-2:2014 called Light and
Lighting—Lighting of Work Places,
Part 2: Outdoor Work Places
2014 E4 25
(Building facade)
1000
(sign) no
CIE 150: 2017, the Guide on the
Limitation of the Effects of
Obstructive Light from Outdoor
Lighting Installations
2017 E4 25
(Building facade)
1000
(sign) yes
ILP’s Professional Lighting Guide
(PLG 05):
The Brightness of Illuminated
Advertisement
2014 E4
600
(up to 10 m2
illuminated area)
300
(over 10 m2
illuminated area)
no
ANSI/IES RP-39-19, Recommended
Practice: Off-Roadway Sign
Luminance
2019 LZ2 40 no
IDA’s Guidance for Electronic
Message Centers (EMCs) 2019 LZ2 40 yes
The lack of unified guidelines makes it extremely difficult for local authorities to make educated
decisions when it comes to dealing with applications for building permits of this kind. Additionally, in
2016, the document Features of and the Evaluation Criteria for LED Outdoor Advertising, was created
in Europe. It was designed to help facilitate application procedures and can be used when submitting
written applications to gain permission to install an LED outdoor advertising system [39].
A more accessible global framework should lead to more awareness about the numerous problems
caused by light pollution. Where there are threats of serious or irreversible light pollution from
media architecture and LED displays, the lack of full scientific certainty should not be used as a
reason for postponing such precautionary or preventive approaches. Restrictions on lighting practices
must be established whilst creating a sustainable environment for effective energy-related products,
environmentally friendly lighting practices, and night environment protection.
2.3. Future Trends in Display Technology
Although LED video displays are still expensive, there has been a notable decrease in price in
recent years. Estimates by IHS Markit indicate they will be even more affordable in the near future [
57
].
This technology already offers intense brightness of screens (greater than the 3000 cd/m
2
suitable for
outdoor daytime environments). Their form and size can be custom-made, and the display can have a
smooth surface without any frames/bezels to provide an undisturbed image. Lastly, with a narrow,
less than 2 mm pixel pitch (NPP), they can provide brighter high-resolution videos. All of the above
means we should expect more of this technology in our cities, which, unless properly controlled,
will significantly increase light pollution.
3. Research Hypotheses
In order to accomplish the research goals and examine how modern non-static, self-luminous LED
displays are significantly increasing problematic light pollution, this study developed the following
operational hypothesis:

Sustainability 2019,11, 3446 10 of 33
Hypothesis 1 (H1).
Media architecture and non-static, self-luminous LED displays are increasing urban light
pollution due to the uncontrolled levels of excessive vertical luminance, an absence of tools to adequately record
and verify the measured data, and a lack of unified lighting design standards that can help to minimize and
mitigate the issues.
4. Materials and Methods
This scientific study involved a mixed-methods research approach to simultaneously collect,
analyze, and interpret both quantitative and qualitative data (Table 5), including a Field Measurement
Survey (Step 1) and a Photographic Survey (Step 2).
Table 5.
An overview of hypotheses and respective qualitative and quantitative methods used for the
analysis, based on observed measured phenomena. Source: authors’ elaboration.
Hypothesis Subject Studied Method
Hypothesis
Urban light pollution
Site-wide photographic survey (to identify over-lighting, light
trespass, and discomfort glare impacting visual wellbeing)
A field measurement survey of nighttime visual luminance (Lv)
to verify recommended levels
Comparison and evaluation of achieved results in relation to
literature examples
Appropriate
measuring tools
A field measurement survey of nighttime visual luminance (Lv)
with a standard luminance meter
Design standards
and guidelines
Literature review (comparative and critical analysis of current
research papers, standards, and technical legislation)
4.1. Field Measurement Survey (Step 1)
This research method was applied to help identify and evaluate the possible exceeded vertical
luminance levels of LED displays/illuminated advertisements in the windows on the main shopping
street of Banhofstrasse in Zurich, Switzerland (Figure 4). This area was chosen for the following two
reasons: (1) in 2004, the City of Zurich established the Plan Lumiere (an urban lighting masterplan) [
58
]
to provide lighting guidelines on an urban scale, but recommendations regarding the illumination of
shop windows and advertising are lacking; (2) since 2015, there has been an unprecedented increase in
the installation of animated LED displays.
Bahnhofstrasse is one of the world’s most expensive shopping streets and it is considered a fine
example of an exclusive shopping avenue by other cities in Europe and overseas. In 2018, a study
by Cushman and Wakefield [
59
] named it the fourth most expensive street for retail property in
Europe, and the ninth most expensive worldwide. The street is approximately 1.4 km long with
shops, banks, coffee houses, restaurants, and hotels located on both sides. It begins with Station
Square (Bahnhofplatz) in front of the main Railway Station Building (Zurich Hauptbanhof), passes
Paradeplatz, and ends at Lake Zurich with Burkliplatz Paradeplatz adjacent to the street, which is
one of the most famous squares in the city, with the main headquarters of two of the largest Swiss
banks: Credit Suisse Group and UBS. As this renown street sets a precedent, if rules are established for
LED animated advertising, it is very likely the rest of the world will consider them important. Field
measurements were conducted in 27 locations.

Sustainability 2019,11, 3446 11 of 33
Sustainability 2019, 11, x FOR PEER REVIEW 11 of 34
(Bahnhofplatz) in front of the main Railway Station Building (Zurich Hauptbanhof), passes
Paradeplatz, and ends at Lake Zurich with Burkliplatz Paradeplatz adjacent to the street, which is
one of the most famous squares in the city, with the main headquarters of two of the largest Swiss
banks: Credit Suisse Group and UBS. As this renown street sets a precedent, if rules are established
for LED animated advertising, it is very likely the rest of the world will consider them important.
Field measurements were conducted in 27 locations.
Figure 4. Banhofstrasse, Zurich, Switzerland: an overview of existing locations of LED displays in
2019. Data was estimated from a site-wide survey. Source: authors’ figure.
4.1.1. Procedure
A photometric measurement of vertical luminance (Lv) on site was performed in March 2019, in
the evening between 20:30 and 22:00 during dry, cloudless weather conditions with the following
commonly available tools: (1) a luminance meter, (2) a digital reflex camera for luminance
photography, and (3) a new video luminance meter mobile phone application (Figure 5). The
measurements were taken as viewed from the point of emission with the measuring cell of the video
luminance meter mobile phone application positioned parallel to the display surface.
Figure 4.
Banhofstrasse, Zurich, Switzerland: an overview of existing locations of LED displays in
2019. Data was estimated from a site-wide survey. Source: authors’ figure.
4.1.1. Procedure
A photometric measurement of vertical luminance (L
v
) on site was performed in March 2019,
in the evening between 20:30 and 22:00 during dry, cloudless weather conditions with the following
commonly available tools: (1) a luminance meter, (2) a digital reflex camera for luminance photography,
and (3) a new video luminance meter mobile phone application (Figure 5). The measurements were
taken as viewed from the point of emission with the measuring cell of the video luminance meter
mobile phone application positioned parallel to the display surface.

Sustainability 2019,11, 3446 12 of 33
Sustainability 2019, 11, x FOR PEER REVIEW 12 of 34
Figure 5. An example of the results from a typical outdoor luminance measurement in cd/m
2
taken
by a video luminance meter mobile phone application with a false color image function for easy
evaluation. False color assigns different colors to areas of different luminance exposure in the image.
Source: Opticalight’s figure.
The measuring device encompassed the whole of the display including parts of its surroundings,
and when required, took into account the field of view based on color discrimination perceived by
the human eye (Figure 6). Precaution was taken when recording data to ensure no shadow from the
person measuring the light produced by the LED display under investigation interfered with the
captured data, as this would result in inaccurate results. We first tried to obtain data using standard
tools such as a luminance meter (1) and a digital reflex camera for luminance photography (2), but,
unfortunately, due to the constant movement of the LED display in both instances, the luminance
meter sensor could not focus, and in the case of the digital reflex camera, the obtained frame/picture
was significantly delayed so it was not possible to obtain any correct values for L
v
. Due to the above
reasons, we were unable to use traditional, established, and standardised methods for recording
measurements of luminance levels using measurement point grids [60].
Figure 5.
An example of the results from a typical outdoor luminance measurement in cd/m
2
taken by a
video luminance meter mobile phone application with a false color image function for easy evaluation.
False color assigns different colors to areas of different luminance exposure in the image. Source:
Opticalight’s figure.
The measuring device encompassed the whole of the display including parts of its surroundings,
and when required, took into account the field of view based on color discrimination perceived by the
human eye (Figure 6). Precaution was taken when recording data to ensure no shadow from the person
measuring the light produced by the LED display under investigation interfered with the captured data,
as this would result in inaccurate results. We first tried to obtain data using standard tools such as a
luminance meter (1) and a digital reflex camera for luminance photography (2), but, unfortunately, due
to the constant movement of the LED display in both instances, the luminance meter sensor could not
focus, and in the case of the digital reflex camera, the obtained frame/picture was significantly delayed
so it was not possible to obtain any correct values for L
v
. Due to the above reasons, we were unable
to use traditional, established, and standardised methods for recording measurements of luminance
levels using measurement point grids [60].

Sustainability 2019,11, 3446 13 of 33
Sustainability 2019, 11, x FOR PEER REVIEW 13 of 34
Figure 6. The setup for luminance measurements of non-static LED displays taking into account the
vertical and horizontal field of view of color discrimination by the human eye. Source: authors’ figure
based on Reference [61].
While searching for a solution to our problem, we came across the mobile phone application
Candela App which allowed us to obtain false color video recordings with a calibrated candela per
square meter spectrum. After a review of the whole recording, we could identify the vertical
luminance (Lv) values by stopping the frame Additionally, we could obtain an image as shown in this
research. All still images were taken from videos.
The Candela App should be used only as a first step to evaluate if the luminance levels are over
the recommended values, based on the CIE EN12464-2:2014 (Table 2) building facade luminance
requirements. This helps avoid the unnecessary inconvenience involved with contacting the shop,
restaurant or business owner/s and needing to then change the lighting setting just to take
measurements as recommended in the ANSI/IES RP-39-19, Recommended Practice: Off-Roadway
Sign Luminance document.
Figure 6.
The setup for luminance measurements of non-static LED displays taking into account the
vertical and horizontal field of view of color discrimination by the human eye. Source: authors’ figure
based on Reference [61].
While searching for a solution to our problem, we came across the mobile phone application
Candela App which allowed us to obtain false color video recordings with a calibrated candela per
square meter spectrum. After a review of the whole recording, we could identify the vertical luminance
(L
v
) values by stopping the frame Additionally, we could obtain an image as shown in this research.
All still images were taken from videos.
The Candela App should be used only as a first step to evaluate if the luminance levels
are over the recommended values, based on the CIE EN12464-2:2014 (Table 2) building facade
luminance requirements. This helps avoid the unnecessary inconvenience involved with contacting
the shop, restaurant or business owner/s and needing to then change the lighting setting just to take
measurements as recommended in the ANSI/IES RP-39-19, Recommended Practice: Off-Roadway Sign
Luminance document.

Sustainability 2019,11, 3446 14 of 33
4.1.2. Analysis and Hypothesis Testing
Our experimental measurement campaign needed validation by data error analysis (e.g., the
calculation of mean, standard deviation, relative percentage error).
Additionally, a scatter plot was used to validate two-dimensional data with dots to represent
two different variables—one plotted along the x-axis (number of installations) and the other plotted
along the y-axis (luminance values obtained from the outdoor luminance measurements in cd/m
2
).
This provides a visual reference that reveals how much luminance levels have increased over the
permitted amount.
The set up for luminance measurement of non-static LED displays (Figure 5) relates to the visual
field geometry of the human eye, which involves a viewer’s cone of vision and related viewing
angles. When standing, the normal line of sight is approximately 10 degrees below the horizontal [
61
].
Depending on the particular color, the color starts to disappear between 30 degrees and 60 degrees of
line of sight.
4.2. Photographic Survey (Step 2)
A photographic survey was performed which involved taking a nighttime photograph of each
LED display to document and record the installation measurements, as well as to evaluate the numerous
visual and physical characteristics of the installations.
Procedure
After recording luminance measurements, an image of each display was taken by a digital camera
mounted on a tripod and positioned in the plane perpendicular to the line of sight towards the middle
of the LED display that encompassed the whole image.
4.3. Technical Equipment
The following professional equipment was used to perform the lighting research (Table 6).
Table 6.
Overview of technical equipment used to measure visual luminance (L
V
). Source:
authors’ elaboration.
Category Company Model No. of Items
Luminance Meter Konica Minolta LS-100 1
Camera Photometer (Digital
Reflex Camera for
Luminance Photography)
Techno Team LMK Mobile air 1
LMK LabSoft software Techno Team NA 1
Mobile Phone Apple Apple iPhone 5S
Operating system iOS 1
Video Luminance Meter
Mobile Phone Application
(Figure 5)
Opticalight Candela Smartphone App
Version 4.2.1 1
Photo Camera Canon
Camera reflex Model
CANON EOS D100D—DC
18-55 Manual settings
(Aperture f/5.6, Shutter
Speed 1/25s, ISO 400)
1
5. Results: Hypothesis Testing
In the presented research study, a field measurement survey was carried out to determine the
extent of light pollution and the amount of obstructive light produced by non-static, self-luminous LED

Sustainability 2019,11, 3446 15 of 33
displays located in the Zurich city center on the main shopping street, with some commercial activities
at night. The results are shown in Table 7. They consist of a nighttime photograph of the LED display
related to its specific location, and the maximum and minimum values of vertical visual luminance
(cd/m
2
) of each display. Additionally, the minimum and maximum sizes and display resolutions, and
any lighting control observed, were included in the results of the photographic survey evaluation.
5.1. Results: An Overview
Out of 28 measured locations (Table 7), four of the LED displays were broken (location No.: 1, 5,
7, 16), so values of vertical luminance could not be measured. No pre-curfew times were observed,
nor were there strict requirements of luminance levels applied to control obstructive light. Also, only
one LED display (location No.: 6a) employed a daylight sensor which adjusts the luminance levels to
outdoor lighting conditions (luminance increases by day and decreases by night).
Table 7.
Banhofstrasse, Zurich, Switzerland: a detailed overview of the results of non-static,
self-luminous LED advertisement displays in regard to their location, ownership, the display’s
nighttime photograph and size, any lighting control used, and its maximum and minimum luminance
values. Source: authors’ data.
Location
on Plan
Business
Type/Name
Nighttime
Photograph Display Size Lighting
Control
Maximum/Minimum
Vertical Luminance
Values 1(cd/m2)
1 Tobacco Shop Broken Display Broken Display NA Broken Display
2Dosenbach
Shoe Store
Sustainability 2019, 11, x FOR PEER REVIEW 15 of 34
In the presented research study, a field measurement survey was carried out to determine the
extent of light pollution and the amount of obstructive light produced by non-static, self-luminous
LED displays located in the Zurich city center on the main shopping street, with some commercial
activities at night. The results are shown in Table 7. They consist of a nighttime photograph of the
LED display related to its specific location, and the maximum and minimum values of vertical visual
luminance (cd/m2) of each display. Additionally, the minimum and maximum sizes and display
resolutions, and any lighting control observed, were included in the results of the photographic
survey evaluation.
5.1. Results: An Overview
Out of 28 measured locations (Table 7), four of the LED displays were broken (location no.: 1, 5,
7, 16), so values of vertical luminance could not be measured. No pre-curfew times were observed,
nor were there strict requirements of luminance levels applied to control obstructive light. Also, only
one LED display (location no.: 6a) employed a daylight sensor which adjusts the luminance levels to
outdoor lighting conditions (luminance increases by day and decreases by night).
Table 7. Banhofstrasse, Zurich, Switzerland: a detailed overview of the results of non-static, self-
luminous LED advertisement displays in regard to their location, ownership, the display’s nighttime
photograph and size, any lighting control used, and its maximum and minimum luminance values.
Source: authors’ data.
Location
on Plan Business Type/Name Nighttime
Photograph Display Size Lighting
Control
Maximum/
Minimum Vertical
Luminance Values 1
(cd/m2)
1 Tobacco Shop Broken Display
Broken
Display NA Broken Display
2 Dosenbach
Shoe Store
160 cm × 300
cm no
375/15
160 cm × 300
cm no
3 Yooji’s
Restaurant
90 cm × 160
cm no 30/2
4 Salt
Mobile Device Store
60 cm × 100
cm no
548/31
60 cm × 100
cm no
5 H&M
Clothes Store Broken Display 200 cm × 250
cm NA Broken Display
160 cm ×300 cm no 375/15
160 cm ×300 cm no
3Yooji’s
Restaurant
Sustainability 2019, 11, x FOR PEER REVIEW 15 of 34
In the presented research study, a field measurement survey was carried out to determine the
extent of light pollution and the amount of obstructive light produced by non-static, self-luminous
LED displays located in the Zurich city center on the main shopping street, with some commercial
activities at night. The results are shown in Table 7. They consist of a nighttime photograph of the
LED display related to its specific location, and the maximum and minimum values of vertical visual
luminance (cd/m2) of each display. Additionally, the minimum and maximum sizes and display
resolutions, and any lighting control observed, were included in the results of the photographic
survey evaluation.
5.1. Results: An Overview
Out of 28 measured locations (Table 7), four of the LED displays were broken (location no.: 1, 5,
7, 16), so values of vertical luminance could not be measured. No pre-curfew times were observed,
nor were there strict requirements of luminance levels applied to control obstructive light. Also, only
one LED display (location no.: 6a) employed a daylight sensor which adjusts the luminance levels to
outdoor lighting conditions (luminance increases by day and decreases by night).
Table 7. Banhofstrasse, Zurich, Switzerland: a detailed overview of the results of non-static, self-
luminous LED advertisement displays in regard to their location, ownership, the display’s nighttime
photograph and size, any lighting control used, and its maximum and minimum luminance values.
Source: authors’ data.
Location
on Plan Business Type/Name Nighttime
Photograph Display Size Lighting
Control
Maximum/
Minimum Vertical
Luminance Values 1
(cd/m2)
1 Tobacco Shop Broken Display
Broken
Display NA Broken Display
2 Dosenbach
Shoe Store
160 cm × 300
cm no
375/15
160 cm × 300
cm no
3 Yooji’s
Restaurant
90 cm × 160
cm no 30/2
4 Salt
Mobile Device Store
60 cm × 100
cm no
548/31
60 cm × 100
cm no
5 H&M
Clothes Store Broken Display 200 cm × 250
cm NA Broken Display
90 cm ×160 cm no 30/2
4Salt
Mobile Device
Store
Sustainability 2019, 11, x FOR PEER REVIEW 15 of 34
In the presented research study, a field measurement survey was carried out to determine the
extent of light pollution and the amount of obstructive light produced by non-static, self-luminous
LED displays located in the Zurich city center on the main shopping street, with some commercial
activities at night. The results are shown in Table 7. They consist of a nighttime photograph of the
LED display related to its specific location, and the maximum and minimum values of vertical visual
luminance (cd/m2) of each display. Additionally, the minimum and maximum sizes and display
resolutions, and any lighting control observed, were included in the results of the photographic
survey evaluation.
5.1. Results: An Overview
Out of 28 measured locations (Table 7), four of the LED displays were broken (location no.: 1, 5,
7, 16), so values of vertical luminance could not be measured. No pre-curfew times were observed,
nor were there strict requirements of luminance levels applied to control obstructive light. Also, only
one LED display (location no.: 6a) employed a daylight sensor which adjusts the luminance levels to
outdoor lighting conditions (luminance increases by day and decreases by night).
Table 7. Banhofstrasse, Zurich, Switzerland: a detailed overview of the results of non-static, self-
luminous LED advertisement displays in regard to their location, ownership, the display’s nighttime
photograph and size, any lighting control used, and its maximum and minimum luminance values.
Source: authors’ data.
Location
on Plan Business Type/Name Nighttime
Photograph Display Size Lighting
Control
Maximum/
Minimum Vertical
Luminance Values 1
(cd/m2)
1 Tobacco Shop Broken Display
Broken
Display NA Broken Display
2 Dosenbach
Shoe Store
160 cm × 300
cm no
375/15
160 cm × 300
cm no
3 Yooji’s
Restaurant
90 cm × 160
cm no 30/2
4 Salt
Mobile Device Store
60 cm × 100
cm no
548/31
60 cm × 100
cm no
5 H&M
Clothes Store Broken Display 200 cm × 250
cm NA Broken Display
60 cm ×100 cm no 548/31
60 cm ×100 cm no
5H&M
Clothes Store Broken Display 200 cm ×250 cm NA Broken Display

Sustainability 2019,11, 3446 16 of 33
Table 7. Cont.
Location
on Plan
Business
Type/Name
Nighttime
Photograph Display Size Lighting
Control
Maximum/Minimum
Vertical Luminance
Values 1(cd/m2)
6a
PKZ Women
Clothes Store
Sustainability 2019, 11, x FOR PEER REVIEW 16 of 34
6a
PKZ Women
Clothes Store
720 cm × 720
cm
yes/no
581/2
6b
100 cm × 160
cm 218/8
7 Tally Weijl
Clothes Store Broken Display 150 cm × 160
cm NA Broken Display
8 UBS Bank Branch
80 cm × 160
cm
no 465/20
80 cm × 160
cm
80 cm × 160
cm
9 PKZ Men
Clothes Store
100 cm × 170
cm
no 480/45
100 cm × 170
cm
10 Grieder
Clothes Store
110 cm × 180
cm no 369/15
11 Bachmann Bakery
200 cm × 300
cm no 347/3
12 Sunrise
Mobile Device Store
100 cm × 50
cm
no 262/1
100 cm × 50
cm
100 cm × 50
cm
100 cm × 50
cm
13 Beldona Lingerie and
Sleepwear Store
170 cm × 80
cm no 1353/20
720 cm ×720 cm
yes/no
581/2
6b
Sustainability 2019, 11, x FOR PEER REVIEW 16 of 34
6a
PKZ Women
Clothes Store
720 cm × 720
cm
yes/no
581/2
6b
100 cm × 160
cm 218/8
7 Tally Weijl
Clothes Store Broken Display 150 cm × 160
cm NA Broken Display
8 UBS Bank Branch
80 cm × 160
cm
no 465/20
80 cm × 160
cm
80 cm × 160
cm
9 PKZ Men
Clothes Store
100 cm × 170
cm
no 480/45
100 cm × 170
cm
10 Grieder
Clothes Store
110 cm × 180
cm no 369/15
11 Bachmann Bakery
200 cm × 300
cm no 347/3
12 Sunrise
Mobile Device Store
100 cm × 50
cm
no 262/1
100 cm × 50
cm
100 cm × 50
cm
100 cm × 50
cm
13 Beldona Lingerie and
Sleepwear Store
170 cm × 80
cm no 1353/20
100 cm ×160 cm 218/8
7Tally Weijl
Clothes Store Broken Display 150 cm ×160 cm NA Broken Display
8UBS Bank
Branch
Sustainability 2019, 11, x FOR PEER REVIEW 16 of 34
6a
PKZ Women
Clothes Store
720 cm × 720
cm
yes/no
581/2
6b
100 cm × 160
cm 218/8
7 Tally Weijl
Clothes Store Broken Display 150 cm × 160
cm NA Broken Display
8 UBS Bank Branch
80 cm × 160
cm
no 465/20
80 cm × 160
cm
80 cm × 160
cm
9 PKZ Men
Clothes Store
100 cm × 170
cm
no 480/45
100 cm × 170
cm
10 Grieder
Clothes Store
110 cm × 180
cm no 369/15
11 Bachmann Bakery
200 cm × 300
cm no 347/3
12 Sunrise
Mobile Device Store
100 cm × 50
cm
no 262/1
100 cm × 50
cm
100 cm × 50
cm
100 cm × 50
cm
13 Beldona Lingerie and
Sleepwear Store
170 cm × 80
cm no 1353/20
80 cm ×160 cm
no 465/20
80 cm ×160 cm
80 cm ×160 cm
9PKZ Men
Clothes Store
Sustainability 2019, 11, x FOR PEER REVIEW 16 of 34
6a
PKZ Women
Clothes Store
720 cm × 720
cm
yes/no
581/2
6b
100 cm × 160
cm 218/8
7 Tally Weijl
Clothes Store Broken Display 150 cm × 160
cm NA Broken Display
8 UBS Bank Branch
80 cm × 160
cm
no 465/20
80 cm × 160
cm
80 cm × 160
cm
9 PKZ Men
Clothes Store
100 cm × 170
cm
no 480/45
100 cm × 170
cm
10 Grieder
Clothes Store
110 cm × 180
cm no 369/15
11 Bachmann Bakery
200 cm × 300
cm no 347/3
12 Sunrise
Mobile Device Store
100 cm × 50
cm
no 262/1
100 cm × 50
cm
100 cm × 50
cm
100 cm × 50
cm
13 Beldona Lingerie and
Sleepwear Store
170 cm × 80
cm no 1353/20
100 cm ×170 cm no 480/45
100 cm ×170 cm
10 Grieder
Clothes Store
Sustainability 2019, 11, x FOR PEER REVIEW 16 of 34
6a
PKZ Women
Clothes Store
720 cm × 720
cm
yes/no
581/2
6b
100 cm × 160
cm 218/8
7 Tally Weijl
Clothes Store Broken Display 150 cm × 160
cm NA Broken Display
8 UBS Bank Branch
80 cm × 160
cm
no 465/20
80 cm × 160
cm
80 cm × 160
cm
9 PKZ Men
Clothes Store
100 cm × 170
cm
no 480/45
100 cm × 170
cm
10 Grieder
Clothes Store
110 cm × 180
cm no 369/15
11 Bachmann Bakery
200 cm × 300
cm no 347/3
12 Sunrise
Mobile Device Store
100 cm × 50
cm
no 262/1
100 cm × 50
cm
100 cm × 50
cm
100 cm × 50
cm
13 Beldona Lingerie and
Sleepwear Store
170 cm × 80
cm no 1353/20
110 cm ×180 cm no 369/15
11 Bachmann
Bakery
Sustainability 2019, 11, x FOR PEER REVIEW 16 of 34
6a
PKZ Women
Clothes Store
720 cm × 720
cm
yes/no
581/2
6b
100 cm × 160
cm 218/8
7 Tally Weijl
Clothes Store Broken Display 150 cm × 160
cm NA Broken Display
8 UBS Bank Branch
80 cm × 160
cm
no 465/20
80 cm × 160
cm
80 cm × 160
cm
9 PKZ Men
Clothes Store
100 cm × 170
cm
no 480/45
100 cm × 170
cm
10 Grieder
Clothes Store
110 cm × 180
cm no 369/15
11 Bachmann Bakery
200 cm × 300
cm no 347/3
12 Sunrise
Mobile Device Store
100 cm × 50
cm
no 262/1
100 cm × 50
cm
100 cm × 50
cm
100 cm × 50
cm
13 Beldona Lingerie and
Sleepwear Store
170 cm × 80
cm no 1353/20
200 cm ×300 cm no 347/3
12
Sunrise
Mobile Device
Store
Sustainability 2019, 11, x FOR PEER REVIEW 16 of 34
6a
PKZ Women
Clothes Store
720 cm × 720
cm
yes/no
581/2
6b
100 cm × 160
cm 218/8
7 Tally Weijl
Clothes Store Broken Display 150 cm × 160
cm NA Broken Display
8 UBS Bank Branch
80 cm × 160
cm
no 465/20
80 cm × 160
cm
80 cm × 160
cm
9 PKZ Men
Clothes Store
100 cm × 170
cm
no 480/45
100 cm × 170
cm
10 Grieder
Clothes Store
110 cm × 180
cm no 369/15
11 Bachmann Bakery
200 cm × 300
cm no 347/3
12 Sunrise
Mobile Device Store
100 cm × 50
cm
no 262/1
100 cm × 50
cm
100 cm × 50
cm
100 cm × 50
cm
13 Beldona Lingerie and
Sleepwear Store
170 cm × 80
cm no 1353/20
100 cm ×50 cm
no 262/1
100 cm ×50 cm
100 cm ×50 cm
100 cm ×50 cm

Sustainability 2019,11, 3446 17 of 33
Table 7. Cont.
Location
on Plan
Business
Type/Name
Nighttime
Photograph Display Size Lighting
Control
Maximum/Minimum
Vertical Luminance
Values 1(cd/m2)
13
Beldona
Lingerie and
Sleepwear
Store
Sustainability 2019, 11, x FOR PEER REVIEW 16 of 34
6a
PKZ Women
Clothes Store
720 cm × 720
cm
yes/no
581/2
6b
100 cm × 160
cm 218/8
7 Tally Weijl
Clothes Store Broken Display 150 cm × 160
cm NA Broken Display
8 UBS Bank Branch
80 cm × 160
cm
no 465/20
80 cm × 160
cm
80 cm × 160
cm
9 PKZ Men
Clothes Store
100 cm × 170
cm
no 480/45
100 cm × 170
cm
10 Grieder
Clothes Store
110 cm × 180
cm no 369/15
11 Bachmann Bakery
200 cm × 300
cm no 347/3
12 Sunrise
Mobile Device Store
100 cm × 50
cm
no 262/1
100 cm × 50
cm
100 cm × 50
cm
100 cm × 50
cm
13 Beldona Lingerie and
Sleepwear Store
170 cm × 80
cm no 1353/20
170 cm ×80 cm no 1353/20
14 Fielmann
Eyewear Shop
Sustainability 2019, 11, x FOR PEER REVIEW 17 of 34
14 Fielmann
Eyewear Shop
70 cm × 120
cm no 2151/12
15 Ochsner Sport
Sporting Goods Store
100 cm × 170
cm no 195/15
16 Manor Department
Store Broken Display 90 cm × 50
cm NA Broken Display
17 Sunrise
Mobile Device Store
60 cm × 30
cm
no 190/2
60 cm × 30
cm
60 cm × 30
cm
60 cm × 30
cm
18 Visilab Zurich
Eyewear Shop
60 cm × 100
cm no 443/14
19 UBS Bank Branch
80 cm × 160
cm no 465/20
20 Hugo Boss Clothes
Store
40 cm × 70
cm
no 112/3
40 cm × 70
cm
40 cm × 70
cm
21 Montblanc Boutique
Store
60 cm × 110
cm
no 73/2
60 cm × 110
cm
22
Beyer
Clock and Watch
Museum
50 cm × 35
cm no 334/115
70 cm ×120 cm no 2151/12
15
Ochsner Sport
Sporting Goods
Store
Sustainability 2019, 11, x FOR PEER REVIEW 17 of 34
14 Fielmann
Eyewear Shop
70 cm × 120
cm no 2151/12
15 Ochsner Sport
Sporting Goods Store
100 cm × 170
cm no 195/15
16 Manor Department
Store Broken Display 90 cm × 50
cm NA Broken Display
17 Sunrise
Mobile Device Store
60 cm × 30
cm
no 190/2
60 cm × 30
cm
60 cm × 30
cm
60 cm × 30
cm
18 Visilab Zurich
Eyewear Shop
60 cm × 100
cm no 443/14
19 UBS Bank Branch
80 cm × 160
cm no 465/20
20 Hugo Boss Clothes
Store
40 cm × 70
cm
no 112/3
40 cm × 70
cm
40 cm × 70
cm
21 Montblanc Boutique
Store
60 cm × 110
cm
no 73/2
60 cm × 110
cm
22
Beyer
Clock and Watch
Museum
50 cm × 35
cm no 334/115
100 cm ×170 cm no 195/15
16
Manor
Department
Store
Broken Display 90 cm ×50 cm NA Broken Display
17
Sunrise
Mobile Device
Store
Sustainability 2019, 11, x FOR PEER REVIEW 17 of 34
14 Fielmann
Eyewear Shop
70 cm × 120
cm no 2151/12
15 Ochsner Sport
Sporting Goods Store
100 cm × 170
cm no 195/15
16 Manor Department
Store Broken Display 90 cm × 50
cm NA Broken Display
17 Sunrise
Mobile Device Store
60 cm × 30
cm
no 190/2
60 cm × 30
cm
60 cm × 30
cm
60 cm × 30
cm
18 Visilab Zurich
Eyewear Shop
60 cm × 100
cm no 443/14
19 UBS Bank Branch
80 cm × 160
cm no 465/20
20 Hugo Boss Clothes
Store
40 cm × 70
cm
no 112/3
40 cm × 70
cm
40 cm × 70
cm
21 Montblanc Boutique
Store
60 cm × 110
cm
no 73/2
60 cm × 110
cm
22
Beyer
Clock and Watch
Museum
50 cm × 35
cm no 334/115
60 cm ×30 cm
no 190/2
60 cm ×30 cm
60 cm ×30 cm
60 cm ×30 cm
18 Visilab Zurich
Eyewear Shop
Sustainability 2019, 11, x FOR PEER REVIEW 17 of 34
14 Fielmann
Eyewear Shop
70 cm × 120
cm no 2151/12
15 Ochsner Sport
Sporting Goods Store
100 cm × 170
cm no 195/15
16 Manor Department
Store Broken Display 90 cm × 50
cm NA Broken Display
17 Sunrise
Mobile Device Store
60 cm × 30
cm
no 190/2
60 cm × 30
cm
60 cm × 30
cm
60 cm × 30
cm
18 Visilab Zurich
Eyewear Shop
60 cm × 100
cm no 443/14
19 UBS Bank Branch
80 cm × 160
cm no 465/20
20 Hugo Boss Clothes
Store
40 cm × 70
cm
no 112/3
40 cm × 70
cm
40 cm × 70
cm
21 Montblanc Boutique
Store
60 cm × 110
cm
no 73/2
60 cm × 110
cm
22
Beyer
Clock and Watch
Museum
50 cm × 35
cm no 334/115
60 cm ×100 cm no 443/14
19 UBS Bank
Branch
Sustainability 2019, 11, x FOR PEER REVIEW 17 of 34
14 Fielmann
Eyewear Shop
70 cm × 120
cm no 2151/12
15 Ochsner Sport
Sporting Goods Store
100 cm × 170
cm no 195/15
16 Manor Department
Store Broken Display 90 cm × 50
cm NA Broken Display
17 Sunrise
Mobile Device Store
60 cm × 30
cm
no 190/2
60 cm × 30
cm
60 cm × 30
cm
60 cm × 30
cm
18 Visilab Zurich
Eyewear Shop
60 cm × 100
cm no 443/14
19 UBS Bank Branch
80 cm × 160
cm no 465/20
20 Hugo Boss Clothes
Store
40 cm × 70
cm
no 112/3
40 cm × 70
cm
40 cm × 70
cm
21 Montblanc Boutique
Store
60 cm × 110
cm
no 73/2
60 cm × 110
cm
22
Beyer
Clock and Watch
Museum
50 cm × 35
cm no 334/115
80 cm ×160 cm no 465/20
20 Hugo Boss
Clothes Store
Sustainability 2019, 11, x FOR PEER REVIEW 17 of 34
14 Fielmann
Eyewear Shop
70 cm × 120
cm no 2151/12
15 Ochsner Sport
Sporting Goods Store
100 cm × 170
cm no 195/15
16 Manor Department
Store Broken Display 90 cm × 50
cm NA Broken Display
17 Sunrise
Mobile Device Store
60 cm × 30
cm
no 190/2
60 cm × 30
cm
60 cm × 30
cm
60 cm × 30
cm
18 Visilab Zurich
Eyewear Shop
60 cm × 100
cm no 443/14
19 UBS Bank Branch
80 cm × 160
cm no 465/20
20 Hugo Boss Clothes
Store
40 cm × 70
cm
no 112/3
40 cm × 70
cm
40 cm × 70
cm
21 Montblanc Boutique
Store
60 cm × 110
cm
no 73/2
60 cm × 110
cm
22
Beyer
Clock and Watch
Museum
50 cm × 35
cm no 334/115
40 cm ×70 cm
no 112/3
40 cm ×70 cm
40 cm ×70 cm

Sustainability 2019,11, 3446 18 of 33
Table 7. Cont.
Location
on Plan
Business
Type/Name
Nighttime
Photograph Display Size Lighting
Control
Maximum/Minimum
Vertical Luminance
Values 1(cd/m2)
21 Montblanc
Boutique Store
Sustainability 2019, 11, x FOR PEER REVIEW 17 of 34
14 Fielmann
Eyewear Shop
70 cm × 120
cm no 2151/12
15 Ochsner Sport
Sporting Goods Store
100 cm × 170
cm no 195/15
16 Manor Department
Store Broken Display 90 cm × 50
cm NA Broken Display
17 Sunrise
Mobile Device Store
60 cm × 30
cm
no 190/2
60 cm × 30
cm
60 cm × 30
cm
60 cm × 30
cm
18 Visilab Zurich
Eyewear Shop
60 cm × 100
cm no 443/14
19 UBS Bank Branch
80 cm × 160
cm no 465/20
20 Hugo Boss Clothes
Store
40 cm × 70
cm
no 112/3
40 cm × 70
cm
40 cm × 70
cm
21 Montblanc Boutique
Store
60 cm × 110
cm
no 73/2
60 cm × 110
cm
22
Beyer
Clock and Watch
Museum
50 cm × 35
cm no 334/115
60 cm ×110 cm no 73/2
60 cm ×110 cm
22
Beyer
Clock and
Watch Museum
Sustainability 2019, 11, x FOR PEER REVIEW 17 of 34
14 Fielmann
Eyewear Shop
70 cm × 120
cm no 2151/12
15 Ochsner Sport
Sporting Goods Store
100 cm × 170
cm no 195/15
16 Manor Department
Store Broken Display 90 cm × 50
cm NA Broken Display
17 Sunrise
Mobile Device Store
60 cm × 30
cm
no 190/2
60 cm × 30
cm
60 cm × 30
cm
60 cm × 30
cm
18 Visilab Zurich
Eyewear Shop
60 cm × 100
cm no 443/14
19 UBS Bank Branch
80 cm × 160
cm no 465/20
20 Hugo Boss Clothes
Store
40 cm × 70
cm
no 112/3
40 cm × 70
cm
40 cm × 70
cm
21 Montblanc Boutique
Store
60 cm × 110
cm
no 73/2
60 cm × 110
cm
22
Beyer
Clock and Watch
Museum
50 cm × 35
cm no 334/115
50 cm ×35 cm no 334/115
23
Credit Suisse
Bank
Headquarter
Sustainability 2019, 11, x FOR PEER REVIEW 18 of 34
23 Credit Suisse Bank
Headquarter
200 cm × 270
cm
no 308/4
200 cm × 270
cm
200 cm × 270
cm
200 cm × 270
cm
200 cm × 270
cm
200 cm × 270
cm
200 cm × 270
cm
200 cm × 270
cm
200 cm × 270
cm
24 USB Bank
Headquarter
160 cm × 80
cm
no 221/8
160 cm × 80
cm
160 cm × 80
cm
160 cm × 80
cm
160 cm × 80
cm
160 cm × 80
cm
25 Kochoptic
Eyewear Shop
70 cm × 120
cm
no 60/3
70 cm × 120
cm
26
Zuricher
Kantonalbank
Headquarter
90 cm × 150
cm
no 593/21
90 cm × 150
cm
27 Buro Zuri
Co-Working Space
90 cm × 150
cm
no 592/21
90 cm × 150
cm
1 The maximum and minimum vertical luminance values were obtained from the video recording
made with the help of the Candela app.
5.2. Hypothesis 1 (H1)
200 cm ×270 cm
no 308/4
200 cm ×270 cm
200 cm ×270 cm
200 cm ×270 cm
200 cm ×270 cm
200 cm ×270 cm
200 cm ×270 cm
200 cm ×270 cm
200 cm ×270 cm
24 USB Bank
Headquarter
Sustainability 2019, 11, x FOR PEER REVIEW 18 of 34
23 Credit Suisse Bank
Headquarter
200 cm × 270
cm
no 308/4
200 cm × 270
cm
200 cm × 270
cm
200 cm × 270
cm
200 cm × 270
cm
200 cm × 270
cm
200 cm × 270
cm
200 cm × 270
cm
200 cm × 270
cm
24 USB Bank
Headquarter
160 cm × 80
cm
no 221/8
160 cm × 80
cm
160 cm × 80
cm
160 cm × 80
cm
160 cm × 80
cm
160 cm × 80
cm
25 Kochoptic
Eyewear Shop
70 cm × 120
cm
no 60/3
70 cm × 120
cm
26
Zuricher
Kantonalbank
Headquarter
90 cm × 150
cm
no 593/21
90 cm × 150
cm
27 Buro Zuri
Co-Working Space
90 cm × 150
cm
no 592/21
90 cm × 150
cm
1 The maximum and minimum vertical luminance values were obtained from the video recording
made with the help of the Candela app.
5.2. Hypothesis 1 (H1)
160 cm ×80 cm
no 221/8
160 cm ×80 cm
160 cm ×80 cm
160 cm ×80 cm
160 cm ×80 cm
160 cm ×80 cm
25 Kochoptic
Eyewear Shop
Sustainability 2019, 11, x FOR PEER REVIEW 18 of 34
23 Credit Suisse Bank
Headquarter
200 cm × 270
cm
no 308/4
200 cm × 270
cm
200 cm × 270
cm
200 cm × 270
cm
200 cm × 270
cm
200 cm × 270
cm
200 cm × 270
cm
200 cm × 270
cm
200 cm × 270
cm
24 USB Bank
Headquarter
160 cm × 80
cm
no 221/8
160 cm × 80
cm
160 cm × 80
cm
160 cm × 80
cm
160 cm × 80
cm
160 cm × 80
cm
25 Kochoptic
Eyewear Shop
70 cm × 120
cm
no 60/3
70 cm × 120
cm
26
Zuricher
Kantonalbank
Headquarter
90 cm × 150
cm
no 593/21
90 cm × 150
cm
27 Buro Zuri
Co-Working Space
90 cm × 150
cm
no 592/21
90 cm × 150
cm
1 The maximum and minimum vertical luminance values were obtained from the video recording
made with the help of the Candela app.
5.2. Hypothesis 1 (H1)
70 cm ×120 cm no 60/3
70 cm ×120 cm
26 Zuricher
Kantonalbank
Headquarter
Sustainability 2019, 11, x FOR PEER REVIEW 18 of 34
23 Credit Suisse Bank
Headquarter
200 cm × 270
cm
no 308/4
200 cm × 270
cm
200 cm × 270
cm
200 cm × 270
cm
200 cm × 270
cm
200 cm × 270
cm
200 cm × 270
cm
200 cm × 270
cm
200 cm × 270
cm
24 USB Bank
Headquarter
160 cm × 80
cm
no 221/8
160 cm × 80
cm
160 cm × 80
cm
160 cm × 80
cm
160 cm × 80
cm
160 cm × 80
cm
25 Kochoptic
Eyewear Shop
70 cm × 120
cm
no 60/3
70 cm × 120
cm
26
Zuricher
Kantonalbank
Headquarter
90 cm × 150
cm
no 593/21
90 cm × 150
cm
27 Buro Zuri
Co-Working Space
90 cm × 150
cm
no 592/21
90 cm × 150
cm
1 The maximum and minimum vertical luminance values were obtained from the video recording
made with the help of the Candela app.
5.2. Hypothesis 1 (H1)
90 cm ×150 cm no 593/21
90 cm ×150 cm
27 Buro Zuri
Co-Working
Space
Sustainability 2019, 11, x FOR PEER REVIEW 18 of 34
23 Credit Suisse Bank
Headquarter
200 cm × 270
cm
no 308/4
200 cm × 270
cm
200 cm × 270
cm
200 cm × 270
cm
200 cm × 270
cm
200 cm × 270
cm
200 cm × 270
cm
200 cm × 270
cm
200 cm × 270
cm
24 USB Bank
Headquarter
160 cm × 80
cm
no 221/8
160 cm × 80
cm
160 cm × 80
cm
160 cm × 80
cm
160 cm × 80
cm
160 cm × 80
cm
25 Kochoptic
Eyewear Shop
70 cm × 120
cm
no 60/3
70 cm × 120
cm
26
Zuricher
Kantonalbank
Headquarter
90 cm × 150
cm
no 593/21
90 cm × 150
cm
27 Buro Zuri
Co-Working Space
90 cm × 150
cm
no 592/21
90 cm × 150
cm
1 The maximum and minimum vertical luminance values were obtained from the video recording
made with the help of the Candela app.
5.2. Hypothesis 1 (H1)
90 cm ×150 cm no 592/21
90 cm ×150 cm
1
The maximum and minimum vertical luminance values were obtained from the video recording made with the
help of the Candela app.
5.2. Hypothesis 1 (H1)
It is often challenging to address the impact of artificial light at night produced by media
architecture and non-static, self-luminous LED displays, as their orientation can make it impractical to
shield them. Since traditional approaches are unsuitable, innovative solutions are needed.

Sustainability 2019,11, 3446 19 of 33
5.2.1. The Number of LED Displays versus Achieved Vertical Luminance
The scatterplot shows a moderately strong, negative, non–linear relationship between the number
of LED displays and their vertical luminance as observed at some outliers (Figure 7). The majority
of businesses displayed one or two LED displays in their shop windows. The highest number of
LED displays in one building was nine (Table 7, LED display location No. 23). There were also
two data points identified (Table 7, LED display location No. 14 and 13) that are unusually far
away from the general pattern. These had the highest vertical luminance values of 2151 cd/m
2
and
1353 cd/m2, respectively.
Sustainability 2019, 11, x FOR PEER REVIEW 19 of 34
It is often challenging to address the impact of artificial light at night produced by media
architecture and non-static, self-luminous LED displays, as their orientation can make it impractical
to shield them. Since traditional approaches are unsuitable, innovative solutions are needed.
5.2.1. The Number of LED Displays versus Achieved Vertical Luminance
The scatterplot shows a moderately strong, negative, non–linear relationship between the
number of LED displays and their vertical luminance as observed at some outliers (Figure 7). The
majority of businesses displayed one or two LED displays in their shop windows. The highest
number of LED displays in one building was nine (Table 7, LED display location no. 23). There were
also two data points identified (Table 7, LED display location no. 14 and 13) that are unusually far
away from the general pattern. These had the highest vertical luminance values of 2151 cd/m
2
and
1353 cd/m
2
, respectively.
Figure 7. A scatterplot showing the relationship between the maximum achieved vertical luminance
and number of LED displays in the year 2019. Source: authors’data.
5.2.2. The Minimum and Maximum Values of Vertical Luminance
The CIE’s current 2017 lighting report document Guide of the Limitation of the Effects of
Obstructive Light from Outdoor Lighting Installations does not differentiate between static and non-
static building facade and sign luminance requirements. Therefore, the maximum permitted values
of the building facade luminance for the environmental zone E4 (high district brightness of city
center) based on the criterion of light pollution prevention of 25 cd/m
2
, was taken as a base for the
evaluation of measured outcomes.
We realized that it was not possible to establish maximum permitted values of average surface
luminance for non-static, self-luminous lighting installations due to the constant changes in
luminance levels with standard measuring tools, so a new measuring tool had to be employed to
achieve levels that could be verified.
The obtained mean of luminance for all 28 measured LED displays was 384.46 (Figure 8), with a
standard deviation (DS) describing the amount of variability of a set of luminance data values of
446.50 and a standard error of the mean (SDM) of 84.38111894. Bearing in mind that 25 cd/m
2
is the
maximum facade luminance limit to minimize urban light pollution, the results indicated that the
values we obtained in our empirical research exceeded the permissible standards between 12 and 18
Figure 7.
A scatterplot showing the relationship between the maximum achieved vertical luminance
and number of LED displays in the year 2019. Source: authors’data.
5.2.2. The Minimum and Maximum Values of Vertical Luminance
The CIE’s current 2017 lighting report document Guide of the Limitation of the Effects of
Obstructive Light from Outdoor Lighting Installations does not differentiate between static and
non-static building facade and sign luminance requirements. Therefore, the maximum permitted
values of the building facade luminance for the environmental zone E4 (high district brightness of city
center) based on the criterion of light pollution prevention of 25 cd/m
2
, was taken as a base for the
evaluation of measured outcomes.
We realized that it was not possible to establish maximum permitted values of average surface
luminance for non-static, self-luminous lighting installations due to the constant changes in luminance
levels with standard measuring tools, so a new measuring tool had to be employed to achieve levels
that could be verified.
The obtained mean of luminance for all 28 measured LED displays was 384.46 (Figure 8), with
a standard deviation (DS) describing the amount of variability of a set of luminance data values of
446.50 and a standard error of the mean (SDM) of 84.38111894. Bearing in mind that 25 cd/m
2
is the
maximum facade luminance limit to minimize urban light pollution, the results indicated that the
values we obtained in our empirical research exceeded the permissible standards between 12 and
18 times, considering the standard error. These results confirmed our hypothesis that self-luminous
LED displays have a substantial impact, increasing urban light pollution due to the uncontrolled levels
of excessive vertical luminance.

Sustainability 2019,11, 3446 20 of 33
Sustainability 2019, 11, x FOR PEER REVIEW 20 of 34
times, considering the standard error. These results confirmed our hypothesis that self-luminous LED
displays have a substantial impact, increasing urban light pollution due to the uncontrolled levels of
excessive vertical luminance.
Figure 8. Mean (average) of luminance for all 28 measured LED displays. Source: authors’ data.
The recorded vertical luminance values of 30 cd/m2 from the LED display (Table 7, location no.
3) seemed to be visually the least disturbing to passive recipients as they walked very close by (Figure
9). This was a 0.2 fold increase of the recommended level by the CIE, and a 1.3 fold increase of that
recommended by the IES. Whereas, the recorded values of 2151 cd/m2 from the animated LED display
(Table 7, location no. 14) appeared to be the most visually disturbing to passive recipients (Figure 10),
as this display showed an 85 fold increase in the level of luminance recommended by the CIE, and a
53 fold increase of that recommended by the IES.
The excessive luminance of LED screens can also create disability glare which temporarily
impairs vision and creates visual discomfort due to the high contrast between the LED screen and
the darker surroundings. It can also damage retinal tissue due to the phototoxic effects of shorter blue
wavelengths of light emitted by LED technology.
384.46
25.00
0.00
50.00
100.00
150.00
200.00
250.00
300.00
350.00
400.00
450.00
Measured luminance Required luminance
Mean (Average)
Figure 8. Mean (average) of luminance for all 28 measured LED displays. Source: authors’ data.
The recorded vertical luminance values of 30 cd/m
2
from the LED display (Table 7, location No. 3)
seemed to be visually the least disturbing to passive recipients as they walked very close by (Figure 9).
This was a 0.2 fold increase of the recommended level by the CIE, and a 1.3 fold increase of that
recommended by the IES. Whereas, the recorded values of 2151 cd/m
2
from the animated LED display
(Table 7, location No. 14) appeared to be the most visually disturbing to passive recipients (Figure 10),
as this display showed an 85 fold increase in the level of luminance recommended by the CIE, and a 53
fold increase of that recommended by the IES.
Sustainability 2019, 11, x FOR PEER REVIEW 21 of 34
Figure 9. Yooji’s Restaurant on Bahnhofstrasse in Zurich, Switzerland, had the lowest luminance
distribution in the field of vision, which provides comfortable eye adaptation. It also had a low level
of brightness relative to its urban surrounding, with a slow pace of changing frames of moving video
images. Source: authors’ figure.
Figure 10. Fielmann Eyewear Shop on Bahnhofstrasse in Zurich, Switzerland, had the highest
luminance distribution in the field of vision, uncomfortable eye adaptation due to its high level of
brightness relative to its urban surrounding, and a fast pace of changing frames of moving video
images. Source: authors’ figure.
5.2.3. The Minimum and Maximum Sizes of the LED Display
The minimum LED display size of 1.75 m2 (location no. 22) was 30 fold smaller than the
maximum size LED display (Table 7, location no.: 6a) which spans a total area of approximately 50
m2 and extends over two building stores. Due to the size and brightness of this LED display no. 6a, it
Figure 9.
Yooji’s Restaurant on Bahnhofstrasse in Zurich, Switzerland, had the lowest luminance
distribution in the field of vision, which provides comfortable eye adaptation. It also had a low level of
brightness relative to its urban surrounding, with a slow pace of changing frames of moving video
images. Source: authors’ figure.

Sustainability 2019,11, 3446 21 of 33
Sustainability 2019, 11, x FOR PEER REVIEW 21 of 34
Figure 9. Yooji’s Restaurant on Bahnhofstrasse in Zurich, Switzerland, had the lowest luminance
distribution in the field of vision, which provides comfortable eye adaptation. It also had a low level
of brightness relative to its urban surrounding, with a slow pace of changing frames of moving video
images. Source: authors’ figure.
Figure 10. Fielmann Eyewear Shop on Bahnhofstrasse in Zurich, Switzerland, had the highest
luminance distribution in the field of vision, uncomfortable eye adaptation due to its high level of
brightness relative to its urban surrounding, and a fast pace of changing frames of moving video
images. Source: authors’ figure.
5.2.3. The Minimum and Maximum Sizes of the LED Display
The minimum LED display size of 1.75 m2 (location no. 22) was 30 fold smaller than the
maximum size LED display (Table 7, location no.: 6a) which spans a total area of approximately 50
m2 and extends over two building stores. Due to the size and brightness of this LED display no. 6a, it
Figure 10.
Fielmann Eyewear Shop on Bahnhofstrasse in Zurich, Switzerland, had the highest luminance
distribution in the field of vision, uncomfortable eye adaptation due to its high level of brightness relative to
its urban surrounding, and a fast pace of changing frames of moving video images. Source: authors’ figure.
The excessive luminance of LED screens can also create disability glare which temporarily impairs
vision and creates visual discomfort due to the high contrast between the LED screen and the darker
surroundings. It can also damage retinal tissue due to the phototoxic effects of shorter blue wavelengths
of light emitted by LED technology.
5.2.3. The Minimum and Maximum Sizes of the LED Display
The minimum LED display size of 1.75 m
2
(location No. 22) was 30 fold smaller than the maximum
size LED display (Table 7, location No.: 6a) which spans a total area of approximately 50 m
2
and extends
over two building stores. Due to the size and brightness of this LED display No. 6a, it generates significant
light trespass into the nearby windows of residential flats and a hotel. Additionally, users of the adjacent
road are constantly exposed to glare (Figure 11). This lighting installation reduces the ability to see
essential information needed to safely navigate the path of travel. Based on the ILP PLG 05 document and
display size, the luminance levels are almost twice the permitted 300 cd/m
2
value. The CIE, IES, and IDA
have no recommendations that limit the luminance levels in regard to the size of an LED display.
Sustainability 2019, 11, x FOR PEER REVIEW 22 of 34
generates significant light trespass into the nearby windows of residential flats and a hotel.
Additionally, users of the adjacent road are constantly exposed to glare (Figure 11). This lighting
installation reduces the ability to see essential information needed to safely navigate the path of
travel. Based on the ILP PLG 05 document and display size, the luminance levels are almost twice the
permitted 300 cd/m2 value. The CIE, IES, and IDA have no recommendations that limit the luminance
levels in regard to the size of an LED display.
Figure 11. The “Walk” LED light art installation integrated into the facade of the PKZ Woman store
on Bahnhofstrasse in Zurich, Switzerland. This was the largest of all the measured LED animated
facade displays, and the disability glare it produces has a definite impact on traffic, negatively
affecting tram drivers. Source: Julia Hartmann’s figure.
5.2.4. The Resolution of LED Displays
The majority of LED displays were high-resolution pixel pitch TV screens, known as video wall
or digital signage, with only one exception (Figure 12) of an LED screen with a low pixel pitch of 30
by 30 mm (Table 7, location no.: 6a).
Figure 12. The “Walk” LED light art installation is integrated into the facade of the PKZ Woman store
on Bahnhofstrasse in Zurich, Switzerland. The LED screen has a low pixel pitch of 30 by 30 mm.
Source: Julia Hartmann’s figure
Figure 11.
The “Walk” LED light art installation integrated into the facade of the PKZ Woman store on
Bahnhofstrasse in Zurich, Switzerland. This was the largest of all the measured LED animated facade
displays, and the disability glare it produces has a definite impact on traffic, negatively affecting tram
drivers. Source: Julia Hartmann’s figure.

Sustainability 2019,11, 3446 22 of 33
5.2.4. The Resolution of LED Displays
The majority of LED displays were high-resolution pixel pitch TV screens, known as video wall or
digital signage, with only one exception (Figure 12) of an LED screen with a low pixel pitch of 30 by
30 mm (Table 7, location No.: 6a).
Sustainability 2019, 11, x FOR PEER REVIEW 22 of 34
generates significant light trespass into the nearby windows of residential flats and a hotel.
Additionally, users of the adjacent road are constantly exposed to glare (Figure 11). This lighting
installation reduces the ability to see essential information needed to safely navigate the path of
travel. Based on the ILP PLG 05 document and display size, the luminance levels are almost twice the
permitted 300 cd/m2 value. The CIE, IES, and IDA have no recommendations that limit the luminance
levels in regard to the size of an LED display.
Figure 11. The “Walk” LED light art installation integrated into the facade of the PKZ Woman store
on Bahnhofstrasse in Zurich, Switzerland. This was the largest of all the measured LED animated
facade displays, and the disability glare it produces has a definite impact on traffic, negatively
affecting tram drivers. Source: Julia Hartmann’s figure.
5.2.4. The Resolution of LED Displays
The majority of LED displays were high-resolution pixel pitch TV screens, known as video wall
or digital signage, with only one exception (Figure 12) of an LED screen with a low pixel pitch of 30
by 30 mm (Table 7, location no.: 6a).
Figure 12. The “Walk” LED light art installation is integrated into the facade of the PKZ Woman store
on Bahnhofstrasse in Zurich, Switzerland. The LED screen has a low pixel pitch of 30 by 30 mm.
Source: Julia Hartmann’s figure
Figure 12.
The “Walk” LED light art installation is integrated into the facade of the PKZ Woman store
on Bahnhofstrasse in Zurich, Switzerland. The LED screen has a low pixel pitch of 30 by 30 mm. Source:
Julia Hartmann’s figure
6. Discussion
The main research goal of this study was to provide an overview of the observed vertical luminance
produced by LED displays from shop windows. An additional aim was to create appropriate and
practical recommendations when applying media architecture and non-static, self-luminous LED
displays in mix-use urban developments.
The results of field measurements and a photographic survey support the hypothesis, and they
highlight why media architecture and non-static, self-luminous LED displays are increasing urban light
pollution due to the uncontrolled levels of excessive vertical luminance. The highest luminance value
recorded was 2151 cd/m
2
which was 86 fold higher than the prescribed building facade luminance
of 25 cd/m
2
. Many other measured on-site LED displays had much higher luminance levels than
permitted. Such displays have a greater impact than a small sign or signage mounted on a building,
as larger-sized LED displays often fill the whole shop window. Therefore, the luminance values should
be much lower and correspond to the display size area. One option could be defining an electric power
allowance for advertising surface (W/m2).
Also, there is an interesting situation observed in Banhofstrasse. Namely, the street seems to be
divided into two visually dissimilar areas at night with cheaper high street retail chains closer to the
railway station, and expensive high-end designer fashion stores towards the lake. The first group of
retailers commonly employ non-static, self-luminous LED displays to attract the attention of younger
viewers/passersby who and are drawn to action and novelty, opposite to the second retailer group,
which target much wealthier, mature consumers who prefer uniqueness and quality. The bold, colorful,
and fast-paced animated displays of the cheaper chain stores do not align with the high-end style of
the street.
Furthermore, banks seem to favor large LED video displays that have consistent brightness and
content. They appear to use a standard factory setting of 500–700 cd/m
2
acceptable for daytime,
but they need be lowered during the night by a considerable degree (existing programmable LED
technology already allows for this.)

Sustainability 2019,11, 3446 23 of 33
This study establishes the relationship between increased light pollution from non-static LED
displays and a lack of proper design standards and guidelines that can help to minimize and mitigate
the issue. The authors propose practical recommendations (Table 8) to help reduce light pollution
and the negative impact of obstructive light on human health and wellbeing, traffic safety, and the
natural environment.
Table 8.
Practical recommendations for LED displays to reduce light pollution and its impact. Source:
authors’elaboration.
Impact On Proposal for Improvement
Human Health and Wellbeing
(Residents/Building Occupiers,
Visitors, Tourists)
•Question the impact of large LED displays in relatively narrow
streets as their viewing will be compromised and the light trespass
they create is likely to be problematic.
•If an LED display on a building facade is located in a residential
area, it should be no brighter than the illuminations on nearby
streets, buildings, and squares that operate during agreed curfew
times. A screen visibility study should be performed.
•The luminance levels of LED displays at night should be lowered
to accommodate mesopic and scotopic vision.
•Allow curfew times. Ideally, all LED displays should be switched
offat the latest by 22:00 in winter and midnight in summer.
Exemptions may be possible for agreed special events, celebrations,
and nominated areas.
•Reduce, or ideally, avoid LED displays that emit blue-rich light
(460–500 nm) and vibrantly colored light at night, as this can have a
profoundly negative effect on the biology of living organisms.
•Place more importance on the colour spectrum or spectral power
distribution (SPD) of a display than its Correlated Color
Temperature (CCT), as this provides important information about
the specific wavelengths of light that are emitted. Choose LEDs
with the most appropriate SPD possible.
•The CCT of light used in LED displays at night should not exceed
2700 K as recommended by the American Medical Association in
Guidance to Reduce Harm from High Intensity Street Lights [62].

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Table 8. Cont.
Impact On Proposal for Improvement
Natural Environment
•
Assess ambient brightness conditions before beginning to work on
any design and its specification, as these are complex issues. The
authors cannot emphasize enough how vital it is to use the services
of professional lighting designers who prioritize nocturnal
placemaking and the reduction of light pollution.
•
Always ensure that an LED display is thoughtfully integrated into
the surrounding architecture and that it fits into and aligns with
the context of its urban setting.
•
Define the environmental zone where each project is located so that
the display does not exceed the permitted level of sky glow, light
intrusion into windows, and building luminance, etc.
•Avoid placing LED displays in residential and recreational areas
near urban parks.
•Follow best practices and guidelines to minimize sky glow, light
trespass, glare, and excess luminance by adhering to the 2019
International Dark-Sky Association Guidance for Electronic
Message Centers (EMCs), as well as the Guide on the Limitation of
the Effects of Obtrusive Light from Outdoor Lighting Installations
from the Commission Internationale de l’Eclairage (CIE) released
in 2017.
•
Limit the excessive luminance of LED displays based on the urban
planning zoning for outdoor lighting control. First, define the
land-use zone where the LED display is located, and based on this
information, assign the appropriate levels.
•Provide lighting scene settings integrated with LED displays
according to the time of the day/night, day of the week, season, and
weather. For instance, rain, mist, fog, and snow will all worsen
glare and increase light pollution.
•Integrate automatic controls to reduce the light output of
installations between daytime and nighttime, and use sensors
and/or time clock facilities.
•Allow curfew times. Ideally, all LED displays should be switched
offat the latest by 22:00 in winter and midnight in summer.
Exemptions may be made for agreed special events, celebrations,
and nominated areas.
•Question the impact of large LED displays in relatively narrow
streets, as their viewing will be compromised and light trespass is
likely to be a problem.
•Apply special louvres and baffles on an LED display to control
light distribution and adjust the angle of light emitted from LED
boards to reduce upward light spill into the atmosphere, prevent
glare from direct view, and minimize light trespass.
•Avoid installing LED displays and digital billboards that generate
electromagnetic interference as this negatively impacts the
performance of cellphones, aviation towers, pacemakers, etc.
•
Limit the specification of large coverage areas/size of LED displays.
•Consider using dark materials for pavement surfaces around the
installation as the light emitted from LED displays can bounce off
the ground back up into the atmosphere to worsen sky glow. Keep
in mind that brighter surfaces will reflect more light.

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Table 8. Cont.
Impact On Proposal for Improvement
Traffic Situation/Transport
System Users (Motorists,
Cyclists, Pedestrians, etc.)
•Avoid placing LED displays near junctions, intersections,
pedestrian crossings, and between pedestrians and vehicles where
increased attention is required. An LED display should not
compete with streetlights or traffic signals/lights.
•Ensure LED displays do not flicker as this can be a source of light
nuisance. It can also produce disturbing stroboscopic effects, such
as trails of lights that can confuse pedestrians, cyclists, and/or
vehicle drivers.
•
Consider the appropriate number of frames per seconds/minutes of
the LED display content to avoid hectic movement of
images/videos. This can disturb pedestrians, compromise their
safety, and distract drivers, resulting in traffic accidents. Flicker
can also trigger migraines and cause disorientation and discomfort.
•Avoid sudden changes in luminance levels of the LED display, as
this can also distract drivers, pedestrians, and cyclists.
As explained in Section 5, it is very difficult to accurately measure and evaluate vertical luminance
from non-static, self-luminous LED displays because of the limitations of commonly used instruments,
so often values are incorrect. For these reasons, a five-step process (Table 9) is proposed until new
approved CIE measuring procedures are introduced. The proposed approach can be applied to any
similar cases and/or conditions.
Table 9.
Overview of the five-step proposed measurement method for non-static LED displays. Source:
authors’ elaboration.
Step Category Description
Step 1 Pre-Analysis with Candela
Application
The authors propose the use of the Candela mobile phone
application, (which operates on iOS devices such as iPhones and
iPads) to help identify and evaluate possible exceeded
luminance levels on site from non-static LED displays [63].
With the application, it is possible to record both surface and
point measurements to determine the luminance outcome in
cd/m2. The app will also display a 2D image in a false color
rendering presentation with value ranges and definable
color gradients.
The app is calibrated for use at 10–1000 cd/m2, 3000 K with
reliable precision. Accuracies of up to 10% are achieved
depending on calibration status. By comparison, the human eye
barely recognizes brightness differences when the light intensity
is doubled. This makes the app a valuable tool for pre-analysis.
It achieves sufficient accuracy as a design aid, but cannot be
used for the verification of legally prescribed measured values.
The application is free of charge and it can be relied on as a
luminance meter on the go, for identifying any potential light
nuisance. At least 5 individual measurements must be made
and they need to be averaged.
Step 2 Data Evaluation After obtaining the luminance data, compare them with the
allowed values. If they exceed them, move to step 3.
Step 3
Gathering Measurements
that Involve Municipality
and Owners/Vendors
Contact your local municipality and request that the
vendor/owner allow proper measurements to be taken of the
non-static LED displays concerned.