Vol.:(0123456789)
1 3
https://doi.org/10.1007/s11252-022-01235-6
Quantifying potential contributions ofgreen facades toenvironmental
justice: acase study ofaquarter inBerlin
EstherS.Felgentreff1 · DavidCochius1· ThomasNehls2· Jan‑HinrichW.Quandt1· EmilJ.Roesch1
Accepted: 12 April 2022
© The Author(s) 2022
Abstract
The potential of green facades (GFs) to enhance environmental justice (EJ) has not been quantified so far. EJ in Berlin,
Germany is assessed by the core indicators (1) noise pollution, (2) air pollution, (3) bioclimatic stress, (4) provision of green
space and (5) social status. Most of the inner city is rated “poorly” in one or multiple indicators. Based on literature and
spatial data, status quo and target values are determined for indicators (1)-(4) for an exemplary, highly burdened quarter in
Berlin. It is assessed if and how much GFs could potentially improve current EJ levels. The improvements due to GFs to reach
target values are assessed in % for day/night and indoor/outdoor settings. It can be shown that installing GFs would improve
statuses of the four indicators to different extents, with the biggest enhancement found regarding indicator (3) for indoors
at daytime: 52%. Determining factors for the EJ improvement potential of GFs need to be further assessed. This feasible
method for increasing the amount of urban green can be helpful for improving life in highly burdened quarters. Therefore,
from the point of view of EJ, large-scale implementation of GFs in urban areas is recommended.
Keywords Environmental justice· Green facades· Noise pollution· Air pollution· Heat stress· Urban greenspace
Introduction
Anthropogenic activities are altering ecosystems on earth to
an unprecedented extent (Foley 2005; Steffen etal. 2015),
generating environmental burdens that are unequally dis-
tributed across society and especially counteracting the
well-being of vulnerable groups (MEA 2005; UNDP 2014;
UNEP 2019).
Developing as a grassroot movement in the USA in the
1980ies (Bullard and Johnson 2000), the concept of envi-
ronmental justice (EJ) now serves as a framework for under-
standing and addressing the issue of unequally distributed
environmental burdens. The US’ Environmental Protection
Agency (EPA 1998, p. 2) defines it as “[t]he fair treatment
and meaningful involvement of all people regardless of race,
color, national origin, or income with respect to the develop-
ment, implementation, and enforcement of environmental
laws, regulations, and policies. Fair treatment means that no
group of people […] should bear a disproportionate share
of the negative environmental consequences resulting from
[human activities]”. Especially in urban areas, people with
low income and a low social status index experience dis-
proportionate exposures to environmental stressors by often
being constrained in the choice of their living environment,
leading to adverse health effects and lower quality of life
(Corburn 2017; Allen etal. 2019).
This topic is also gaining recognition in Germany (UBA
2009), where in recent years the state of Berlin developed
an approach to map EJ by assessing the following five core
indicators, categorizing the status of each indicator as low,
medium, or high: (1) noise pollution, (2) air pollution, (3)
bioclimatic stress, (4) provision of green space and (5) social
status (SenStadtUm 2015a). Acknowledging that it is also
possible to assess EJ differently than through these indica-
tors, we adopted Berlin’s concept for this paper. It is not the
aim of this paper to question, discuss and improve this EJ
concept.
An approach to assess patterns of EJ more differentiated
than the three classes used by Berlin’s senate is proposed
by Lakes etal. (2013), who use the example of Berlin to
develop an index to quantify the relative degree of EJ of
* Esther S. Felgentreff
esther.felgentreff@posteo.de
1 Institute ofEcology, Technische Universität Berlin, Berlin,
Germany
2 Institute ofEcology, Chair forEcohydrology andLandscape
Evaluation, Technische Universität Berlin, Berlin, Germany
/ Published online: 4 May 2022
Urban Ecosystems (2022) 25:1417–1430
1 3
residential areas on the level of planning units. We however
decided to use the official calculations of the Berlin Senate
as a baseline here.
In line with this, the World Health Organization (WHO)
(2011, 2018b) outlines environmental noise, and in par-
ticular road traffic noise, as one of the top environmental
risks to health, linking it to sleep disturbance, cognitive
impairment, or cardiovascular disease. In Germany, over
20% of the inhabitants within urban areas are exposed to
noise levels harmful to health (EEA 2020). Further, air
pollution is estimated to be related to 4.2 million prema-
ture deaths worldwide in 2016, even though the emitted
amount has been declining for about two decades (WHO
2018b). In this regard, particulate matter ≤ 2.5µm (PM2.5)
and nitrogen dioxide (NO2) emitted by energy production,
traffic, or industry are two of the main health threaten-
ing substances, being associated with increased bronchi-
tis symptoms, reduced lung function, cardiovascular and
respiratory diseases, or different kinds of cancer (WHO
2018b). The third indicator, bioclimatic stress, comprises
the sum of all climatic factors that influence the thermo-
physiological condition of humans, including air tem-
perature, wind velocity, air humidity, and the incoming
solar radiation, referring to a state of thermal discomfort.
This can lead to so-called “heat stress” or “cold stress”
(Matzarakis and Mayer 1996; Matzarakis and Amelung
2008; Mayer etal. 2008; SenStadtUm 2011, 2015a),
whereby here and in the following, only heat stress will
be considered. Due to the urban heat island effect, this is
a problem especially in urban areas (Dimoudi etal. 2013).
Heat stress has several adverse health effects and causes
numerous deaths (Matzarakis and Mayer 1996; Robine
etal. 2008; Gabriel and Endlicher 2011). Particularly the
lack of nightly indoor cooling leading to partial sleep dis-
order is thought to play a major role (Nicholls etal. 2008;
Kenny etal. 2019). Additionally, the provision of green
space comes into focus as green urban spaces are highly
valued for their recreational purposes, allowing a certain
compensation of the environmental burdens experienced
in densely built areas or serving for environmental educa-
tion. Today, in the context of urbanization and climate
and demographic change, there is even more pressure
on greenspaces within cities to fulfil multiple purposes
with as little cost as possible (Garske 2011). While ver-
tical green spaces are obviously different to horizontal
green spaces, it can be expected that vertical ones pro-
vide important ecosystem services especially in densely
populated areas with deficient green space provision. As
in these quarters, new parks are unlikely to be built, it
is worthwhile to assess the potential of green facades
(GFs) as an implementable option to improve the living
conditions.
Eventually, the fifth indicator social status is not a
direct environmental burden and cannot be thought to be
improved by a change in nearby green space. However,
it demonstrates high vulnerability when coming together
with one or more of the other four indicators and puts them
in the context of EJ.
In the assessment of EJ in Berlin, most of the inner
city is rated “poorly” in one or multiple of the indica-
tors, emphasizing the need for structural improvement
measures. Research suggests that vertical greenery sys-
tems (VGSs) can positively influence indicators (1)-(4)
– whereby indicator (4) needs to be discussed in further
detail (Ottelé etal. 2010; Wong etal. 2010a; Hoelscher
etal. 2016; Radić etal. 2019) –but not the indicator (5),
social status.
This study aims at quantifying the maximum potential
of green facades as one type of VGSs to enhance EJ as this
has not been done so far. Contrary to living walls (LWs)
which consist of vertical panels or geotextile felts with a
growing medium for low growing plants which typically
develop on a horizontal base, GFs usually apply climber
plants planted at the base of a building, using its facade or
trellises or ropes as growing support (Pérez etal. 2011;
Perini etal. 2013). There exist different nomenclatures
for facade greening techniques, but this study follows
the nomenclature where “VGS” is the generic term for
all types, and “GFs” and “LWs” are the two subtypes as
described by Radić etal. (2019).
LWs, however, require considerably higher installation
and maintenance costs than GFs, making their large-scale
implementation in low-income areas infeasible (Perini and
Rosasco 2013). Regarding the intention of improving EJ,
this study focuses on GFs, due to their easier implemen-
tation, higher data availability and lower structural com-
plexity, which allows for better comparability between the
investigated factors. Fear of facade damage due to VGS,
which accounts especially for GFs, is a misconception, as
plants growing and rooting directly at a facade only pose
a risk if walls are already damaged (Ottelé 2011).
No matter which greening system is used, it should be
noted that greening the whole facade area is not realistic.
This is not only due to architectonic features such as win-
dows, balconies, etc. but also because of sustainability
concerns such as limited water availability (Pearlmutter
etal. 2021).
In this study, based on literature and spatial data, status
quo and target values to reach EJ are determined for the
indicators (1)-(4) for a highly burdened exemplary quar-
ter in Berlin. We purposely exclude indicator (5), social
status, from the calculations, as installing a GF will obvi-
ously not affect the social status. However, we choose an
exemplary quarter with a low social status index, as it is
1418 Urban Ecosystems (2022) 25:1417–1430
1 3
the limited adaptability capacities of these communities
that require discussions of EJ but also proactive reductions
of environmental burdens.
Subsequently, the maximum potential contribution of GFs
to achieve the set target values is assessed and quantified for
the examined indicators.
Materials andmethods
An exemplary street in the district Berlin-Gesundbrunnen
was chosen as the case study site. In the Environmental Jus-
tice Atlas, this site is classified as highly burdened, as it is
categorized as medium burdened by noise pollution, highly
burdened by air pollution and heat stress, has low access to
green space, and a low social status index (SenSW 2015).
In this area, residential buildings from the Wilhelminian
period built in perimeter block type are prevalent. This type
is the most common in Berlin, and roughly a third of Berlin’s
residents live in such buildings (SenS 2011). The area and
these buildings can therefore be considered representative of
a highly environmentally burdened, however typical Berlin
housing situation.
The example buildings presumed for this study are 22m
high, 10m wide and have four storeys. We analyzed a street
canyon with two rows of such buildings with the ratio of
height to width = 1, meaning that the street width is 22m.
A 40m long section of this canyon is looked at, i.e., four
houses as described above on either side of the street.
The ‘status quo’ was investigated by collecting status quo
values for the four indicators based on available information
from the municipality of Berlin. We then assume a poten-
tial ‘greened case’ in which this canyon section is greened
hypothetically. 70% of the street-facing walls of the example
buildings are assumed to be eligible for greening, while the
remaining 30% are windows and doors (Loga etal. 2011).
The area of the greened facades for the two sides of the street
is therefore 40mx22mx0.7 × 2 = 1232 m2. The utilized
plant Parthenocissus tricuspidata (Boston ivy) is commonly
used on facades (Preiss 2013). This study refers to a period
in which the plant bears leaves. It is assumed that no street
trees are present in the section to avoid mixing the effects of
trees and the GF. For each indicator, values for this predicted
‘greened case’ were determined.
Then, ‘target values’ which describe a desirable target
state of these indicators were researched. It is assumed that
if the status quo value equals or exceeds the target value,
EJ would be “achieved”. The differences between status
quo and target values were determined as the "gaps" which
must be closed to “achieve” EJ. The difference between the
status quo value and the predicted greened case contribu-
tion is referred to as the ‘EJ-improving potential of GFs’,
calculated as contribution in % of the full "gap", described
above. Wherever possible, a distinction was made between
day and night as well as between indoor and outdoor.
Noise pollution
The evaluation of the EJ improving potential of GFs regard-
ing the indicator noise pollution is based on a literature
review. Regarding attenuation effects, the focus in this study
lies on urban road traffic noise with relatively low speeds
and a main frequency spectrum at low to middle frequen-
cies around 500–1000hertz (Hz) (Feldmann and Volz 2000;
Nilsson and Forssén 2013), as this is the most dominant
source of urban noise and its associated adverse health
effects (van Kempen and Babisch 2012; EEA 2020). The sta-
tus quo values for the exemplary quarter were derived from
the maps 07.05.1Strategische Lärmkarte LDEN Straßen-
verkehr (SenSW 2017) and 07.05.2 Strategische Lärmkarte
LNight Straßenverkehr (SenSW 2017) of the geodata portal
FIS-Broker. The dominant outdoor sound pressure levels at
the facades are 75 A-weighted decibel (dB(A)) at day and
65dB(A) at night (data for 2017). For indoor sound pres-
sure levels, a default attenuation of -21dB(A) compared to
outdoors was assumed, as described in the Good Practice
Guide on Noise Exposure and Potential Health Effects (EEA
2010). This results in status quo indoor sound pressure val-
ues of 54dB(A) at day and 44dB(A) at night.
These values were compared with target values for envi-
ronmental noise set by the WHO to prevent adverse health
effects, recommending outdoor sound levels not exceeding
55dB(A) at day and 45dB(A) at night. For indoor sound
levels, target values of 35dB(A) at day and 30dB(A) inside
bedrooms at night are provided for continuous background
noise (WHO 1999, 2009, 2018a). For the noise reduction
potential of GFs, existing research on noise attenuation
effects of VGSs was examined to derive precise values in
db(A). These values relate to the attenuation in sound pres-
sure due to installing GFs.
The value for outside noise reduction by GFs found in
literature with best comparability to the depicted exemplary
conditions in this work was modelled for a 400m long street
canyon with 16m width and 20m high fully vegetated build-
ing facades on both sides. The noise immission was deter-
mined at a height of 2m. Outdoor sound pressure levels
are stated to be around 1.5dB(A) lower with this type of
VGS (Feldmann and Volz 2000). The indoor noise attenua-
tion potential of GFs refers to an in-situ measurement of its
acoustic insulation capacity according to the UNE-EN ISO
140-5 standard, conducted at a cubicle of 3m width, length,
and height. A double-skin GF was installed by attaching a
simple wire mesh covered with a 0.2–0.3m thick layer of
vegetation with P. tricuspidata parallel to the wall of the
cubicle in a distance of 0.25m. For the measurements inside
1419Urban Ecosystems (2022) 25:1417–1430
1 3
the cubicle, noise was emitted by a speaker 2.3m in front
of the facade at a height of 1.2m. In this study, an increased
sound insulation of 1dB(A) for traffic noise indoors was
found (Pérez etal. 2016).
Air pollution
Status quo values for the key indicator air pollution were
taken from the FIS-Broker map Umweltgerechtigkeit:
Kernindikator Luftbelastung (Umweltatlas) on EJ (annual
means for 2009) (SenStadtUm 2015b). Therefore, con-
centrations of 32.11µg/m3 NO2 and 23.44µg/m3 PM2.5,
respectively, are used for both day and night. To determine
target values for an ‘environmental just’ status, threshold
values set by the European Union and the WHO were com-
pared to the target values in the EJ monitoring of Berlin
(WHO 2018b; SenUVK 2019; UBA 2019). The lowest
set values found in one of the three previously mentioned
sources were taken as target values for this study. These
are 17.1µg/m3 NO2 from the EJ report and 10µg/m3 for
PM2.5 from the WHO (2018a).
Pugh etal. (2012) calculated specific values for the
reduction of NO2 and PM10 concentrations by green walls
using a model simulation. The simulation took place in
central London, UK which has a similar climate to Berlin
(Pfadenhauer and Klötzli 2014). Reduction potentials as
shown in the graphs are 2.7µg/m3 for NO2 and 3.3µg/m3
for PM2.5. Pugh etal. (2012) do not consider the reduction
of PM2.5, but as other research suggests, it can be expected
to even exceed PM10 reduction (Vardoulakis etal. 2003;
Litschke and Kuttler 2008; Ottelé etal. 2010). We how-
ever assumed that PM2.5 and PM10 do not differ, so that the
calculation of Pugh etal. (2012) could be used. Indoor air
pollution reduction by GFs has hardly been researched so
far, hence no values are calculated for this part of the study.
Heat stress
Buchin etal. (2016) developed an equation to calculate the
indoor temperature at time t + Δt of a building:
Tin(t) = indoor temperature at time t; Tout = outdoor tem-
perature;
λ = solar temperature elevation constant;
I = incoming horizontal radiation; τ = time constant
They adjusted Eq.(1) to be specifically for the sec-
ond floor of a west exposed residential Wilhelminian
building, being partly shaded by other buildings (i.e., not
(1)
T
in(t+Δt)=Tout +𝜆I+(Tin(t)−Tout −𝜆I)exp(
−Δt
𝜏)
free-standing). They modelled the building in the simu-
lation program EnergyPlus, entered climate data, and
simulated indoor temperatures. With these, Eq.(1) was
parameterized and calibrated, yielding values for the two
parameters τ and λ (τ = 4.115*105s, a measure for the
thermal inertia of the building, and λ = .025 m2K/W,
representing the temperature elevation due to solar gains)
(Buchin etal. 2016).
Buchin etal. (2016) shared the weather dataset they
used for their calculations with us, consisting of hourly
measured temperatures in Potsdam from the Deutsche Wet-
terdienst (DWD) and global horizontal short-wave radia-
tion data from a weather station at Technische Universität
Berlin in Berlin-Steglitz (Buchin etal. 2016). Here, data
from summer 2003 was used, which was a record hot sum-
mer in many parts of Europe (Robine etal. 2008) and dur-
ing which Berlin also experienced several consecutive hot
days. Indoor temperatures were calculated using Eq.(1).
The heating period during which the indoor temperatures
are determined by a heating system was set to end April 30
and begin October 1 (Mieterschutzbund Berlin e.V. n.d.).
The observed period was set to May 1–September 30, and it
was assumed that there was no air conditioning or other
cooling measure. Indoor temperatures during the heating
period were assumed to be 22°C during day and 18°C
during night, meaning that at midnight on April30, 18°C
was the present indoor temperature when calculations of
the indoor temperatures began on May 1, 1:00 am. The
temperatures were calculated in hourly resolution. Then,
daily and nightly mean values were calculated for each
day from hourly data, from 6 am to 9pm and 10pm to 5
am, respectively. The temperature profiles are visualized
in graphs. The highest of these mean values was taken as
the status quo value.
For daytime, the WHO’s Guidelines on Healthy Living
recommend 25°C maximum in temperate regions (WHO
2018c). Different approaches to setting a target value
for night-time temperature exist. Here, it is set to 24°C
(CIBSE 2006 as cited in Kenny etal. 2019).
No effect of the GF on the outdoor temperatures is
assumed (Hoelscher etal. 2016). Hoelscher etal. (2016)
found over 80% of the cooling effect on a building to be
caused by shading, especially during hot summer days.
As the evapotranspiration cooling effect mainly depends
on water supply, only shading is considered. It should be
noted that the actual effect can be assumed to be even
higher than calculated here. This shading effect of the
plants is approximated by lowering the incoming solar
radiation I by an additional factor β (2).
(2)
T
in(t+Δt)=Tout +𝛽𝜆I+(Tin(t)−Tout −𝛽𝜆I)exp(
−Δt
𝜏)
1420 Urban Ecosystems (2022) 25:1417–1430
1 3
Tin(t) = indoor temperature at time t; Tout = outdoor tem-
perature;
ß = additional factor to account for facade greening;
λ = solar temperature elevation constant;
I = incoming horizontal radiation; τ = time constant
Through the 30% of the facade which is uncovered, the
solar radiation arrives unfiltered, while on the remaining 70%
it is reduced by the plants. Transmissivity of P. tricuspidata
was calculated to be 0.386 based on Monsi (2004) and own
measurements forleaf area index (leaf surface per wall surfa-
cae, LAI) (1.9) and the attenuation coefficientk (0.5). For that,
photos of the facade greening were taken in front of a reference
plate mounted between the plants and the wall. Leaves were
cut and its areas determined using a xerox and image analysis.
The leaf areas were divided by the reference plate area to cal-
culate vertical LAIs. The attenuation coefficients were derived
from analyses of images regarding the leaf orientations.
The radiation still arriving at the facade is described with
the factor β:
With this, the indoor temperatures for the greened case
were calculated. The EJ-improving potential of GFs was
determined as described in 2.1. As the objective was to
study the full potential of GFs, the maximum improve-
ment was used.
Provision ofgreenspace
The data on greenspace and population density in the
exemplary quarter was downloaded from the Berlin geo-
data portal FIS-Broker. It includes the maps Grünan-
lagenbestand Berlin (einschließlich der öffentlichen
Spielplätze) (SenSW 2020) and Einwohnerdichte 2018
(Umweltatlas) (SenSW 2019) as well as the encoded
attribute data on the area extent of greenspaces, popula-
tion density in each block.
A guideline for sufficient greenspace supply and a defi-
nition of the desired proximity of greenspace to people’s
homes is provided by the Senate Administration for Urban
development and housing of Berlin. It was published in 1995
as Versorgung mit öffentlichen, wohnungsnahen Grünan-
lagen and still acts as a measure of greenspace supply in
Berlin, e.g. for its targets for EJ (SenStadtUm 2015a) and
provides the values for Table1. It should be noted that the
guideline differentiates between two types of accessibility,
smaller greenspaces close to residents’ homes and larger
greenspaces within the area. Vertical greenspaces are not
explicitly excluded in this guideline. The different functions
fulfilled by horizontal versus vertical green spaces are com-
pared in the discussion.
(3)
𝛽=0.3 ∗1+0.7 ∗0.368 =0.5702
The data was downloaded and processed using the
software QGIS (v.3.12.2-București). As preparation
for analysis, an exemplary block was chosen and a line
shapefile created, representing the modelled GF. Then,
buffers of 500m and 1000m were created to delineate
the catchment areas as described in Table1. The mini-
mum size requirements for the area of greenspaces to
be counted were not applied, as except for one big park,
they would have concluded that there was no greenspace
in the study area and made it impossible to measure
anything. As the GF covers an area smaller than the pro-
posed minimum values and as in this study, small-scale
effects are investigated, these minimum values were
neglected.
Consequently, the number of inhabitants and the area
of greenspace within 500m and 1000m were calculated
from the aforementioned attribute data. Equations(4)–(6)
were applied to calculate EJ-improving potential of GFs.
G = Area of greenspace within a 500m radius; I = Number
of inhabitants within a 500m radius;
S = Status quo greenspace per capita ratio in m
2
person
G = Area of greenspace within a 500m radius; F = Area
of GF in greened case; I = Number of inhabitants within
a 500m radius;
R = Greenspace per capita ratio in m
2
person
in greened case
R = Greenspace per capita ratio in m
2
person
in greened case;
S = Status quo greenspace per capita ratio in m
2
person
;
T = Target value in m
2
person
; EJIP = EJ-improving potential
of GFs
(4)
G
I
=S
(5)
G+F
I
=
P
(6)
R−S
T−S
=
EJIP
Table 1 Provision of green space rate per capita for open spaces in
the catchment areas, a planning basis according to the Senate Admin-
istration for Urban development and housing of Berlin
Greenspace close
to home Greenspace close
to residential area
Minimum size 0.5ha 10ha
Reference value 6m
2
resident
7m
2
resident
Maximum distance 500m 1000m
1421Urban Ecosystems (2022) 25:1417–1430
1 3
Results
Noise pollution
We found an EJ-improving potential by GFs of 1dB(A)
or 5.3% during day and 1dB(A) or 7.1% during night for
indoors. For outdoors, we calculated an EJ-improving
potential by GFs of 1.5dB(A) or 7.5% during day and night
(Table2).
Air pollution
The pollutant concentration reduction corresponds to an EJ-
improving potential of GFs of 18.2% NO2 and 24.4% PM2.5,
respectively (Table2). Hence, the mean improvement for
indicator air pollution can be stated to be 21.3% for a com-
bination of both pollutants. Since the status quo values are
annual means, the same air quality improvement is assumed
for day and night. As specified in 2.2, no values for indoor
pollutant reduction could be calculated.
Heat stress
Temperature values over the summer period of 2003 are
shown in Figs.1 and 2. Note that these are mean values,
and higher peaks during the afternoon are attenuated. Three
hotter periods during early June, mid-July and beginning to
mid-August are visible. In early May, daily indoor tempera-
tures (long dashed lines) were approximately average out-
door temperatures, but after a few days the building heats up
and the indoor temperatures of the building with the blank
facade (status quo values) remain slightly higher than the
outdoor temperatures. Generally, indoor temperature values
are subject to less fluctuation than outdoor temperatures.
Predicted indoor temperatures in the greened case (solid
lines) are visibly lower than those behind the blank facades.
While both temperature profiles begin with the same start
value on May 1 after the end of the heating period, they
separate soon and the blank building heats up more and
quicker. Generally, both curves run quite parallel. The
difference between the indoor temperatures of the blank
and the greened building increases with higher outdoor
temperatures.
With 31.2°C, the highest daily indoor mean temperature
during summer 2003 in Berlin occurred on August 13. As
the daytime indoor target value is 25°C, there is a differ-
ence of 6.2°C. The maximal difference between indoor tem-
peratures with and without GF during daytime was 3.2°C,
occurring on both June 13 and 14. The EJ-improving poten-
tial of GFs to close the gap between status quo and target
Table 2 Status quo and target values of the four examined indicators of Environmental Justice and contribution of Green Facades (GF) at differ-
ent daytimes, indoor and outdoor
Indicator Location Time Status quo value Target value Difference between
status quo and target
value
EJ-improving potential
by GFs
Noise Pollution Indoor Day 54dB(A) 35dB(A) 19dB(A) 1dB(A) 5.3%
Night 44dB(A) 30dB(A) 14dB(A) 1dB(A) 7.1%
Outdoor Day 75dB(A) 55dB(A) 20dB(A) 1.5dB(A) 7.5%
Night 65dB(A) 45dB(A) 20dB(A) 1.5dB(A) 7.5%
Air Pollution Indoor Day/PM2.5 - - - - -
Night/PM2.5 - - - - -
Day/NO2- - - - -
Night/ NO2- - - - -
Outdoor Day/PM2.5 23.4µg/m310µg/m313.4µg/m33.3µg/m324.4%
Night/PM2.5 23.4µg/m310µg/m313.4µg/m33.3µg/m324.4%
Day/NO232.1µg/m317.1µg/m315µg/m32.7µg/m318.2%
Night/ NO232.1µg/m317.1µg/m315µg/m32.7µg/m318.2%
Heat Stress Indoor Day 31.2°C 25°C 6.2°C 3.2°C 51.6%
Night 31°C 24°C 7°C 3.1°C 44.3%
Outdoor Day - - - - -
Night - - - - -
Provision of green space Indoor Day - - - - -
Night - - - - -
Outdoor Day 3.8 m2/ person 6 m2/ person 2.2 m2/ person 0.016 m2/ person 1.6%
Night 3.8 m2/ person 6 m2/ person 2.2 m2/ person 0.016 m2/ person 1.6%
1422 Urban Ecosystems (2022) 25:1417–1430
1 3
value at daytime can therefore be quantified with up to a
maximum of 51.6% at the hottest period of the day (Table2).
The highest nightly indoor mean temperature during
summer 2003 in Berlin occurred as well on August 13 at
31.0°C. As the night-time target value is 24°C, there is
a difference of 7°C. A comparison of Fig.1 and 2 clearly
shows how the outdoor temperatures cool down during the
nights, whereas the indoor temperatures drop little or not at
all, visualizing the trapped heat within buildings and the lack
of night-time cooling.
The maximal difference between indoor tempera-
tures with and without GF during night-time was 3.1°C,
occurring in the nights of June 9, 10, 13 and 14. The EJ-
improving potential of GFs at night-time can therefore be
quantified with up to 44.3% (Table2).
Provision ofgreenspace
Figure3 shows the catchment area, the position of the GF
and the buffer areas. For the 500m catchment area, the
potential improvement was 1.6%. The 1000m catchment
area was already above the target value, so no improvement
could be simulated.
Fig. 1 Daytime (6 am-9 pm)
mean outdoor (short dashed
line) and calculated indoor
temperatures of a blank facade
(status quo; long dashed line,
data is taken from Buchin etal.
2016) and a greened facade
(greened case; solid line) of a
typical Berlin residential build-
ing between May 1 and Sep-
tember 30, 2003. The values for
each day are calculated as the
mean of hourly data between 6
am and 9pm. No effect of green
facades on the outdoor tempera-
ture is assumed
Fig. 2 Nighttime (10 pm-5 am)
mean outdoor (short dashed
line) and calculated indoor
temperatures of a blank facade
(status quo; long dashed line,
data is taken from Buchin etal.
(2016) and a greened facade
(greened case; solid line) of a
typical Berlin residential build-
ing between May 1 and Sep-
tember 30, 2003. The values for
each night are calculated as the
mean of hourly data between
10pm and 5 am. No effect of
green facades on the outdoor
temperature is assumed
1423Urban Ecosystems (2022) 25:1417–1430
1 3
Discussion
The results regarding the noise pollution attenuation poten-
tial of GFs show that vegetated street canyons reduce the
propagation of road traffic noise, although their contribu-
tion is rather limited and does not exceed 1.5dB(A) (see
Table2). This is partly explained by the aboveground veg-
etation components such as leaves and stems that absorb and
scatter sound mainly at high frequencies (Wong etal. 2010b;
Yang etal. 2013; Pérez etal. 2016). The acoustic effective-
ness of GFs is therefore relatively small in the low frequency
spectrum of road traffic noise (Forssén etal. 2014). Further-
more, noise reduction levels of up to 8dB(A) or more that
are attributed solely to plant materials in literature, usually
assume vegetation belts of a few meters depth that are rela-
tively rich in biomass (Cook and van Haverbeke 1975; Van
Renterghem etal. 2012). These values are unrealistic to be
achieved in the limited space of urban street canyons.
Nevertheless, even the stated values should be treated
with care as real conditions foster complexity and many
factors influence the acoustic performance of GFs. Accord-
ingly, not only characteristics of the environment and the
noise itself impact the acoustic performance of VGSs but
also plant-related factors. For example a larger amount of
foliage, leaf area density, or dominant angle of leaf orienta-
tion results in an improved noise reduction capacity (Wong
etal. 2010b; Horoshenkov etal. 2013; Nilsson and Forssén
2013). Although this study focussed on GFs, we would like
to add that also the presence of substrate as part of a LW can
substantially enhance the acoustic performance of VGSs in
lower frequencies, as shown by Azkorra etal. (2015), Pérez
etal. (2016), Wong etal. (2010b). The latter measured noise
reductions of around 5–10dB for different types of VGSs.
However, a consistent conclusion cannot be drawn as
studies regarding the noise attenuation effects of vegetation
incorporated in buildings usually refer to green roofs and the
consideration of VGSs is scarce (Azkorra etal. 2015; Pérez
etal. 2016). In addition, due to the wide range of different
VGSs and their varying acoustic behavior, the studied types
of VGSs as well as the methodologies and outcomes differ
considerably, hence hindering generalization (Azkorra etal.
2015). It should be emphasized that also the experimen-
tal set-up of the consulted studies partly differed from the
assumptions of this work, so that for example the increased
street width of 6m assumed in this study potentially results
in a decreased noise reduction potential of VGSs in street
canyons (Feldmann and Volz 2000; Forssén etal. 2014).
Finally, Van Renterghem etal. (2013) also highlight the
dependence of the measured noise attenuation effects of a
VGS from the assumption of the material characteristics in
the reference case. Consequently, the noise reduction effects
of GFs presented in this study should be understood as
approximate values revealing the relatively low potential of
GFs to contribute to noise attenuation. In this regard, future
research should rather focus on noise abatement effects by
LWs as their acoustic performance seems to be more promis-
ing according to the mentioned studies.
The EJ-improving potential of GFs in mitigating air pol-
lution is comparatively high (see Table2), even though there
are numerous determining factors that need to be further
Fig. 3 Modelled green facades
(GF) in Berlin-Gesundbrunnen
with 500m and 1000m param-
eters and the according housing
blocks as well as greenspaces;
Created in QGIS (v.3.12.2-
București), using data from FIS-
Broker (SenSW 2018, 2020)
1424 Urban Ecosystems (2022) 25:1417–1430
1 3
analyzed. Some plants emit biogenic volatile organic com-
pounds (bVOCs) that can add to ozone formation under
urban conditions where nitrogen oxide concentrations are
high (Matsunaga etal. 2017; Fitzky etal. 2019). Leung etal.
(2011) and Benjamin and Winer (1998) stated the emission
of bVOCs to be especially high when plants are facing water
stress, high temperatures and high solar radiation intensi-
ties. Most research on this subject focuses on emissions
from trees and shrubs. Further investigation of climbing
species’ emissions is necessary. This also applies to plant
pollen emissions, which are another possible health impact
of VGSs due to possible allergic reactions. Bergmann etal.
(2012) classified urban plants in Berlin in terms of pollen
emissions and left out climbing plants completely from his
study. Also, particle resuspension, which means removal of
particles via wind or rain, is a field that needs to be further
investigated (Reznik and Schmidt 2009; Ottelé etal. 2010).
Since P. tricuspidata is not evergreen, its EJ improvement
potential is hardly applicable for winter. Concurrently, an
improvement of air quality is especially important in winter:
The urban boundary layer is lower than in summer, leading
to a near-surface pollutant accumulation (DWD 2017). Addi-
tionally, there are higher emissions in winter due to heating.
The fact that there are no values for the indoor pollutant
reduction by GFs is due to lacking research. Nevertheless,
there exists a strong correlation between indoor and out-
door pollutant concentrations (Diapouli etal. 2007; Ji and
Zhao 2015; Leung 2015): less pollutants in street canyons
will lead to lower concentrations indoors. That, however,
depends on indoor ventilation: Opening windows leads to
higher air exchange rates which lead to similar pollutant
rates indoors and outdoors.
Also, no separate values for day and night can be deter-
mined since the observed values are long term means. Any-
way, it can be presumed that reductions by day will be higher
since there are more pollutants present in street canyons
because of higher traffic emissions and higher small-scale
turbulences during daytime.
The specific number of captured particles and gaseous
pollutants also strongly depends on the street canyon ratio
and the LAI, rising with higher values for these factors
(Pugh etal. 2012; Abhijith etal. 2017). The uptake of other
substances is not considered in this study since the Berlin
EJ assessment considers only NO2 and PM2.5. Nevertheless,
these pollutants are not the only ones being taken up by
or settle on GFs. Jayasooriya etal. (2017) also detected an
uptake of SO2, CO and O3.
GFs can considerably ameliorate the state of indoor heat
stress in urban areas. The potential of GFs to mitigate heat
stress as determined here is the highest of the four indicators
(see Table2). This is in line with numerous studies about the
effect of VGS on the temperature of a building (Wong etal.
2010a; Cameron etal. 2014; Hoelscher etal. 2016; Šuklje
etal. 2016). As the heat stress risk will rise in the future due
to climate change, an increase of extreme weather events
(IPCC 2014), accelerating urbanization and urban densifi-
cation, thus more intense UHI (UN DESA 2019), and the
demographic change (Dugord etal. 2014), the heat stress
aspect of EJ will get more and more relevant. The remark-
ably high reduction of the indoor heat stress by a simple GF
underlines its high potential to be applied as climate change
adaptation measure.
To investigate heat stress, it is advisable to consider
indoor rather than outdoor temperatures. This is because
urban vulnerable groups spend 80–90% of their time
indoors (Brasche and Bischof 2005; Buchin etal. 2016;
Kenny etal. 2019), so they are exposed to indoor heat stress
considerably more than to outdoor conditions. Climatic and
temperature patterns differ between outdoors and indoors,
meaning that conclusions drawn from analyses done out-
doors are not transferable to indoor conditions. The com-
parison between Fig.1 and 2 visualizes that there is a less
considerable effect of night-time cooling indoors than
occurring outdoors.
To predict indoor temperatures, we chose a physically
based, rather conservative approach by considering only the
shading impact of GFs. Simulations on such scale are usu-
ally subject to uncertainties. However, we chose the most
appropriate approach according to Buchin etal. (2016) and
only reduced the incoming radiation by adding factor β. Val-
idation of the model was however out of scope for this study.
Despite that, the EJ-enhancing potential of GFs was found to
be considerably high here. Future studies should furthermore
include the other cooling effects of plants, namely insulation
and evapotranspiration, which will likely result in a greater
cooling potential by GFs than predicted here.
The assumption that GFs have no effects on the outdoor
climate in the street canyon should also be tested again, as
existing studies came to different results. While Hoelscher
etal. (2016) and Šuklje etal. (2016) could not detect cool-
ing effect of GFs on the street canyon, Djedjig etal. (2013,
2015a, b, 2016) measured in a reduced-scale experiment mar-
ginally cooler temperature in greened canyons. Alexandri and
Jones (2008) simulated up to 2.5°C lower temperatures in
a street canyon during the afternoon in temperate climates
using their micro-scale model. If such a cooling effect of
GFs can be proved and quantified, the real indoor cooling
potential of a GF could be higher than assessed here.
Even more than GFs, LW systems can be assumed to have
a greater cooling effect on the building due to the increased
insulation by a thicker layer and additional evapotranspi-
ration by the substrate. On the other hand, the additional
insulation could hinder cooling of the building (Pérez etal.
2011). Indoor temperature is not the only component of
thermal comfort, but is a sufficient predictor for heat stress
(Urban and Kyselý 2014; Buchin etal. 2016). It is therefore
1425Urban Ecosystems (2022) 25:1417–1430
1 3
advised to consider mainly the indoor temperature in evalu-
ations and calculations regarding heat stress, and it is recom-
mended to consider indoor rather than outdoor conditions in
Berlin’s EJ assessment (SenUVK 2019).
Provision of green space stands out from the formerly
discussed indicators for EJ, as it does not revolve around
adverse health effects. Instead, it can be seen as a valuable
resource that can, among other benefits, promote a healthy
lifestyle and reduce stress of urban inhabitants (Haluza etal.
2014).
The minimum area sizes for greenspaces (Table1) to be
counted in the analysis were omitted, because the change
caused by greening a street canyon would not have been
possible to show, as the area of the assumed GF would not
exceed the area necessary for it to be included. However, the
values also seem relatively high, considering that benefits
from GFs are expected (Radić etal. 2019) long before reach-
ing an area this big (0.5 and 10ha). Therefore, this study
argues for a more open approach to urban greening, and a
point was made to count all urban green, no matter the size,
from the data set.
The radius used for assessing greenspace close to peo-
ples’ dwellings was 500m (and 1000m close to residential
areas, respectively), however as Grunewald etal. (2017)
pointed out, they should be in actual walking distance
instead of linear distance to not give a wrong impression of
how far people will go for short range recreation. In their
study, they propose a 300m radius instead. For this work, it
was decided to stick to the radius as chosen by the senate of
Berlin (Table1), however this could have led to a misjudge-
ment of how far people walk to urban greenspace.
The Berlin target value of 6 m2 greenspace per person
within 500m of their home (SenStadtUm 2015a), as used
in this study, seems like a good starting point. It provides a
data base to quantify the lack of urban greenspace in cer-
tain areas and helps to communicate the need for action.
On the other hand, this value seems arbitrarily small, espe-
cially when compared to status quo values in other cities in
Germany which have a median of 8.1 m2. While the actual
values differ considerably throughout the country, from 2.5
m2 in Schwerin to 36 m2 in Bergisch Gladbach (Wüstemann
etal. 2016), we think target values should generally be set
higher, considering the fundamental role of urban greens-
paces for public health, the (micro-)climate and biodiversity.
Russo and Cirella (2018), in accordance with the WHO,
recommend a minimum target value of 9 m2/capita and ide-
ally 50 m2/capita, while recognizing individual solutions for
climatic and structural differences. This again indicates how
much room there is for improving access to and the overall
area of urban greenspace to benefit the public. However, any
value should be viewed with a grain of salt as it acts only as
a tool to identify insufficient provision of green space, and
therefore potential environmental injustice, but should not
be seen as a definite answer, as there is still no consensus on
how much is needed or even recommended.
In the analysis, the area extent of GF is compared to hori-
zontal urban green spaces like parks without a distinction.
There are obvious differences to GFs though, in contrast
to the enterable and tangible nature of a park. In addition,
there are more limitations to the types of plants that can be
established to grow on or in front of a facade.
Yet, GFs are green spaces. They may not be perceived
as green spaces, not because they are of low quality, but
because they do not fulfill the corresponding requirements
in the guideline (SenStadtUm 2015a). This guideline, how-
ever, is insufficient, as it neglects multiple important effects
of green spaces such as social benefits (e.g., community
gardening), visual and educational effects (e.g., observing
wildlife) or habitat provision for wildlife – services that can
be provided by vertical green spaces, too (see Radić etal.
2019). Studies by Haluza etal. (2014), Jonker etal. (2014),
Reid etal. (2017), Astell-Burt and Feng (2019), andTost
etal. (2019) all showed positive health effects of urban green,
especially stress relief. Even though the evidence is not yet
highly conclusive on the causal effects, it is feasible that they
can be transferred to a certain degree to GFs. Accordingly,
Pérez-Urrestarazu etal. (2017) demonstrated positive effects
of VGSs on the mental health of hospital patients.
Regarding accessibility issues and greening the direct
residential surroundings of inhabitants in densely built
quarters, GFs have the advantage to be equally accessible
for all – including for those who cannot leave their homes
–, being visible from the street and from adjacent buildings.
We therefore suggest that a future indicator for assessing
provision of green space incorporates these functions.
In reversing the question, not asking how much improve-
ment to green space targets a GF can contribute, but how
many facades would need to be greened to reach target val-
ues, the extent of the lack of greenspace in the area was
demonstrated. Within the 500m radius of the modelled GF,
2.6km of street canyons would need to be greened to reach
the target value. This GF coverage is difficult to achieve, so it
shows the need for action in urban greening. Even with this
GF coverage, due to the different properties of horizontal
greenspaces and GFs, it is difficult to say if sufficient provi-
sion of green space would have been achieved. GFs are a
viable, but complementary type of urban green and should
not replace greenspaces like parks.
Combinations of multiple stressors can result in inter-
actions, which in turn increase the adverse effects. For
example, Golmohammadi and Darvishi (2019) found that
the combination of noise pollution, air pollution und heat
stress can lead to “hearing loss, hypertension, cardiovascular
effects, psychological effects, and sleep disorder”. Interac-
tions by multiple stressors should thus be subject of further
investigation.
1426 Urban Ecosystems (2022) 25:1417–1430
1 3
When talking about the properties of GFs, note that the
plant species proposed for this study is P. tricuspidata, a
deciduous plant that loses most of its beneficial properties
for the winter months. This plant was chosen as it is one of
the most common plants used for GFs in Germany and is
often considered in research (Preiss 2013), however, ever-
green and similarly common plants like Hedera helix should
also be considered for a real GF.
There are however some points to discuss. A question
coming up is whether justice can even be measured and dis-
cussed as something that can be reached partially. Justice is
a complex social and philosophical concept but a discussion
on its nature goes beyond the scope of this study. Instead,
we stuck to the existing definition of EJ (see Introduction).
Integration of affected groups in society rather than exclud-
ing them from decision-making processes should however
be a prerequisite when talking about justice. Further studies
dealing with this topic are welcome to critically discuss the
approach of quantifying EJ.
Compared to other approaches like green roofs, expen-
sive air filtering technology and cooling systems, GFs are
relatively inexpensive and can be installed in many urban
settings (Preiss 2013). A potential challenge is the feasibil-
ity due to monument protection, as many buildings in Berlin
are classical Wilhelminian and permits could complicate the
process of GF installation.
As already stated in former parts of this section, LWs
might have an even higher potential on mitigation of EJ.
They are supposed to reduce noise pollution (Wong etal.
2010b; Azkorra etal. 2015; Pérez etal. 2016) and heat stress
(Pérez etal. 2011) substantially stronger than GFs. But they
also are more expensive and require more maintenance than
GFs, which prevents them from being economically sustain-
able and attractive in implementation. Even though GFs are
among the cheapest options to implement urban green, and
the resulting recommendation that this is a good measure,
Perini and Rosasco (2013) showed that they could raise the
property value of surrounding neighbourhoods. Due to miss-
ing or inappropriate political regulations of the housing mar-
ket this is potentially on the cost of the people (low income,
low social status) that should benefit from greening efforts
in terms of EJ. Instead, they might be forced to move out
of their former neighbourhood. However, such discussions
should not cynically hinder installation of GFs but rather
demonstrate the need for political regulation. Regarding
vulnerable groups or people with a low social status index,
it should be recognized that their adaptive capacity to the
examined environmental stressors is lower. As stated above,
GFs are an attractive measure since they are low in cost and
required space and thus possible to be implemented on a
larger scale. GFs are neither the solution to environmental
injustices, nor are they completely to be dismissed in aiding
this challenge, but, as shown in this study, are a valuable
addition among other solutions. It should be noted that this
is a rather theoretic study, presenting exact figures, which are
based on other studies and some model case assumptions. It
was our aim to assess the maximum potential impact of GFs
to improve EJ. Having shown that this can be remarkable,
we suggest further empirical investigations.
Conclusion
In this study, the potential of GFs to contribute to EJ in an
exemplary quarter of Berlin was investigated using a novel
approach. This study revealed both the enhancement of
EJ by GFs, and the possibility to quantitatively assess this
improvement.
It was shown that GFs can improve the status of all four
investigated indicators to different extents, whereby the
effect on indoor heat stress at daytime is with up to 51.6%
the largest. The method used in this study proposes a shift
of perspectives from outdoors to indoors when researching
urban heat stress.
GFs should be perceived as green spaces as they pro-
vide numerous ecosystem services. They should therefore
be included in green space provision guidelines. Due to
GF’s comparably low horizontal space requirements, easy
installation, and little costs, GFs can be set in place almost
anywhere in the city, most likely improving the well-being
of adjacent communities. Many different designs of VGSs
with varying properties exist, and these systems can be
adjusted to the requirements of the respective environment
and intended improvements.
Due to the many positive effects and few downsides of
GFs, large-scale installation of GFs in urban areas is recom-
mended especially where the status of the four indicators is
low. The approach to quantify the improvement potential
of GFs aforehand is a starting point for action and further
research can build upon that.
Acknowledgements We thank Oliver Buchin for providing the weather
data set, Karin Hoffmann for critical discussions, and the TU Berlin
for support.We also thank two anonymous reviewers for their very
constructive feedback.
Author contribution All authors contributed to this work in equal parts.
D. C. wrote 2.1 and 3.1 about indicator noise pollution, E. R. wrote
2.2 and 3.2 about indicator air pollution, E. F. wrote 2.3 and 3.3 about
indicator heat stress and J. Q. wrote 2.4 and 3.4 about indicator provi-
sion of green space. All authors contributed to the introduction and
discussion regarding their indicators. D. C. wrote the introduction, E.
F. wrote 2.0 and 2.5., E. R. and J. Q. wrote 4, D. C. and E. F. wrote 5.
T. N. contributed to the concept of the study, discussed its single steps
with the other authors and edited the text.
Funding Open Access funding enabled and organized by Projekt
DEAL. T.N. was funded by the BMBF (German Federal Ministry
1427Urban Ecosystems (2022) 25:1417–1430
1 3
ofEducation and Research) and the JPI (Joint Programming Initiative)
Urban Europe in the projectsVertical Green 2.0(FKZ 01LF1803A)
andBlue-Green Streets(FKZ 033W103G). All other authors declare
that they have no financial interests.
Declarations
Ethics approval Not applicable.
Consent to participate Not applicable.
Consent for publication Not applicable.
Competing interests The authors have no relevant financial or non-
financial interests to disclose.
Open Access This article is licensed under a Creative Commons Attri-
bution 4.0 International License, which permits use, sharing, adapta-
tion, distribution and reproduction in any medium or format, as long
as you give appropriate credit to the original author(s) and the source,
provide a link to the Creative Commons licence, and indicate if changes
were made. The images or other third party material in this article are
included in the article's Creative Commons licence, unless indicated
otherwise in a credit line to the material. If material is not included in
the article's Creative Commons licence and your intended use is not
permitted by statutory regulation or exceeds the permitted use, you will
need to obtain permission directly from the copyright holder. To view a
copy of this licence, visit http:// creat iveco mmons. org/ licen ses/ by/4. 0/.
References
Abhijith KV, Kumar P, Gallagher J etal (2017) Air pollution abatement
performances of green infrastructure in open road and built-up
street canyon environments – a review. Atmos Environ 162:71–
86. https:// doi. org/ 10. 1016/j. atmos env. 2017. 05. 014
Alexandri E, Jones P (2008) Temperature decreases in an urban canyon
due to green walls and green roofs in diverse climates. Build
Environ 43:480–493. https:// doi. org/ 10. 1016/j. build env. 2006.
10. 055
Allen S, Fanucchi MV, McCormick LC, Zierold KM (2019) The search
for environmental justice: the story of North Birmingham. Int
J Environ Res Public Health 16:2117. https:// doi. org/ 10. 3390/
ijerp h1612 2117
Astell-Burt T, Feng X (2019) Association of urban green space with
mental health and general health among adults in Australia. JAMA
Netw Open 2:e198209. https:// doi. org/ 10. 1001/ jaman etwor kopen.
2019. 8209
Azkorra Z, Pérez G, Coma J etal (2015) Evaluation of green walls as
a passive acoustic insulation system for buildings. Appl Acoust
89:46–56. https:// doi. org/ 10. 1016/j. apaco ust. 2014. 09. 010
Benjamin MT, Winer AM (1998) Estimating the ozone-forming poten-
tial of urban trees and shrubs. Atmos Environ 32:53–68. https://
doi. org/ 10. 1016/ S1352- 2310(97) 00176-3
Bergmann K-C, Zuberbier T, Augustin J etal (2012) Klimawandel
und Pollenallergie: Städte und Kommunen sollten bei der Bep-
flanzung des öffentlichen Raums Rücksicht auf Pollenaller-
giker nehmen. Allergo J 21:103–108. https:// doi. org/ 10. 1007/
s15007- 012- 0045-4
Brasche S, Bischof W (2005) Daily time spent indoors in German
homes – Baseline data for the assessment of indoor exposure
of German occupants. Int J Hyg Environ Health 208:247–253.
https:// doi. org/ 10. 1016/j. ijheh. 2005. 03. 003
Buchin O, Jänicke B, Meier F etal (2016) The role of building models
in the evaluation of heat-related risks. Nat Hazards Earth Syst Sci
16:963–976. https:// doi. org/ 10. 5194/ nhess- 16- 963- 2016
Bullard RD, Johnson GS (2000) Environmentalism and public policy:
Environmental justice: Grassroots activism and its impact on
public policy decision making. J Soc Issues 56:555–578. https://
doi. org/ 10. 1111/ 0022- 4537. 00184
Cameron RWF, Taylor JE, Emmett MR (2014) What’s cool in the world
of green façades? How plant choice influences the cooling prop-
erties of green walls. Build Environ 73:38
CIBSE (2006) Guide A, Environmental Design. Chartered Institution
of Building Services Engineers, London
Cook DI, van Haverbeke DF (1975) Suburban noise control with plant
materials and solid barriers. In: U.S. Department of Agriculture,
State University of New York at Syracuse, American Meteorol-
ogy Society (Eds.) The Conference on Metropolitan Physical
Environment. New York, p 234–241
Corburn J (2017) Concepts for studying urban environmental justice.
Curr Environ Health Rep 4:61–67. https:// doi. org/ 10. 1007/
s40572- 017- 0123-6
Diapouli E, Chaloulakou A, Mihalopoulos N, Spyrellis N (2007)
Indoor and outdoor PM mass and number concentrations at
schools in the Athens area. Environ Monit Assess 136:13–20.
https:// doi. org/ 10. 1007/ s10661- 007- 9724-0
Dimoudi A, Kantzioura A, Zoras S etal (2013) Investigation of urban
microclimate parameters in an urban center. Energy Build 64:1–
9. https:// doi. org/ 10. 1016/j. enbui ld. 2013. 04. 014
Djedjig R, Belarbi R, Bozonnet E (2013) Experimental study of a green
wall system effects in urban canyon scene. p 9
Djedjig R, Bozonnet E, Belarbi R (2015a) Experimental study of the
urban microclimate mitigation potential of green roofs and green
walls in street canyons. Int J Low-Carbon Technol 10:34–44.
https:// doi. org/ 10. 1093/ ijlct/ ctt019
Djedjig R, Bozonnet E, Belarbi R (2015b) Analysis of thermal effects
of vegetated envelopes: Integration of a validated model in a
building energy simulation program. Energy Build 86:93–103.
https:// doi. org/ 10. 1016/j. enbui ld. 2014. 09. 057
Djedjig R, Bozonnet E, Belarbi R (2016) Modeling green wall interac-
tions with street canyons for building energy simulation in urban
context. Urban Clim 16:75–85. https:// doi. org/ 10. 1016/j. uclim.
2015. 12. 003
Dugord P-A, Lauf S, Schuster C, Kleinschmit B (2014) Land use pat-
terns, temperature distribution, and potential heat stress risk –
the case study Berlin, Germany. Comput Environ Urban Syst
48:86–98. https:// doi. org/ 10. 1016/j. compe nvurb sys. 2014. 07. 005
DWD (2017) Luftqualität unter der Lupe. Messen - Bewerten - Beraten.
Deutscher Wetterdienst
EEA (2020) Environmental noise in Europe - 2020. European Environ-
ment Agency
EEA (2010) Good practice guide on noise exposure and potential
health effects. European Environment Agency, Luxembourg
EPA (1998) Final guidance for incorporating environmental justice
concerns in EPA’s NEPA compliance analyses. Environmental
Protection Agency
Feldmann J, Volz R (2000) Umweltbelastung durch Verkehrsgeräusche
sowie Aspekte der Schallausbreitung und Schallabsorption in
Straßenschluchten
Fitzky AC, Sandén H, Karl T etal (2019) The interplay between ozone
and urban vegetation—BVOC emissions, ozone deposition, and
tree ecophysiology. Front Glob Change 2:50. https:// doi. org/ 10.
3389/ ffgc. 2019. 00050
Foley JA (2005) Global consequences of land use. Science 309:570–
574. https:// doi. org/ 10. 1126/ scien ce. 11117 72
Forssén J, Hornikx M, Defrance J etal (2014) Toolbox from the EC
FP7 HOSANNA project for the reduction of road and rail traf-
fic noise in the outdoor environment. Holistic and Sustainable
1428 Urban Ecosystems (2022) 25:1417–1430
1 3
Abatement of Noise by optimized combinations of Natural and
Artificial means (HOSANNA), Paris, France, p 10
Gabriel KMA, Endlicher WR (2011) Urban and rural mortality rates
during heat waves in Berlin and Brandenburg, Germany. Environ
Pollut 159:2044–2050. https:// doi. org/ 10. 1016/j. envpol. 2011. 01.
016
Garske T (2011) When is a city green? Technische Universität Ber-
lin, Eine GIS-basierte Methode zur Ermittlung der städtischen
Grünflächen-Versorgung für Erholungszwecke
Golmohammadi R, Darvishi E (2019) The combined effects of occu-
pational exposure to noise and other risk factors − a systematic
review. Noise Health 21:125–141. https:// doi. org/ 10. 4103/ nah.
NAH_4_ 18
Grunewald K, Richter B, Meinel G etal (2017) Proposal of indica-
tors regarding the provision and accessibility of green spaces
for assessing the ecosystem service recreation in the city in Ger-
many. Int J Biodivers Sci Ecosyst Serv Manag 13:26–39. https://
doi. org/ 10. 1080/ 21513 732. 2017. 12833 61
Haluza D, Schönbauer R, Cervinka R (2014) Green perspectives for
public health: a narrative review on the physiological effects of
experiencing outdoor nature. Int J Environ Res Public Health
11:5445–5461. https:// doi. org/ 10. 3390/ ijerp h1105 05445
Hoelscher M-T, Nehls T, Jänicke B, Wessolek G (2016) Quantifying
cooling effects of facade greening: Shading, transpiration and
insulation. Energy Build 114:283–290. https:// doi. org/ 10. 1016/j.
enbui ld. 2015. 06. 047
Horoshenkov KV, Khan A, Benkreira H (2013) Acoustic properties of
low growing plants. J Acoust Soc Am 133:2554–2565. https://
doi. org/ 10. 1121/1. 47986 71
IPCC (2014) Climate Change 2014: Synthesis Report. Contribution of
Working Groups I, II and III to the Fifth Assessment Report of
the Intergovernmental Panel on Climate Change. Intergovern-
mental Panel on Climate Change, Geneva, Switzerland
Jayasooriya VM, Ng AWM, Muthukumaran S, Perera BJC (2017)
Green infrastructure practices for improvement of urban air qual-
ity. Urban Urban Green 21:34–47. https:// doi. org/ 10. 1016/j. ufug.
2016. 11. 007
Ji W, Zhao B (2015) Contribution of outdoor-originating particles,
indoor-emitted particles and indoor secondary organic aerosol
(SOA) to residential indoor PM2.5 concentration: a model-based
estimation. Build Environ 90:196–205. https:// doi. org/ 10. 1016/j.
build env. 2015. 04. 006
Jonker MF, van Lenthe FJ, Donkers B etal (2014) The effect of
urban green on small-area (healthy) life expectancy. J Epide-
miol Community Health 68:999–1002. https:// doi. org/ 10. 1136/
jech- 2014- 203847
Kenny GP, Flouris AD, Yagouti A, Notley SR (2019) Towards estab-
lishing evidence-based guidelines on maximum indoor tem-
peratures during hot weather in temperate continental climates.
Temperature 6:11–36. https:// doi. org/ 10. 1080/ 23328 940. 2018.
14562 57
Lakes T, Brückner M, Krämer A (2013) Development of an environ-
mental justice index to determine socio-economic disparities of
noise pollution and green space in residential areas in Berlin. J
Environ Plan Manag 57:21. https:// doi. org/ 10. 1080/ 09640 568.
2012. 755461
Leung DYC (2015) Outdoor-indoor air pollution in urban environment:
challenges and opportunity. Front Environ Sci. https:// doi. org/ 10.
3389/ fenvs. 2014. 00069
Leung DYC, Tsui JKY, Chen F etal (2011) Effects of urban vegetation
on urban air quality. Landsc Res 36:173–188. https:// doi. or g/ 10.
1080/ 01426 397. 2010. 547570
Litschke T, Kuttler W (2008) On the reduction of urban particle con-
centration by vegetation a review. Metz 17:229–240. https:// doi.
org/ 10. 1127/ 0941- 2948/ 2008/ 0284
Loga T, Diefenbach N, Born R (2011) Deutsche Gebäudetypologie.
Beispielhafte Maßnahmen zur Verbesserung der Energieeffizienz
von typischen Wohngebäuden
Matsunaga SN, Shimada K, Masuda T etal (2017) Emission of bio-
genic volatile organic compounds from trees along streets and in
urban parks in Tokyo. Japan Asian J Atmos Environ 11:4
Matzarakis A, Amelung B (2008) Physiological equivalent temperature
as indicator for impacts of climate change on thermal comfort
of humans. In: Thomson MC, Garcia-Herrera R, Beniston M
(eds) Seasonal Forecasts, Climatic Change and Human Health.
Springer, Netherlands, Dordrecht, pp 161–172
Matzarakis A, Mayer H (1996) Another kind of environmental stress:
Thermal stress. 7–10
Mayer H, Holst J, Dostal P etal (2008) Human thermal comfort in sum-
mer within an urban street canyon in Central Europe. Meteorol
Z 17:241–250. https:// doi. org/ 10. 1127/ 0941- 2948/ 2008/ 0285
MEA (2005) Ecosystems and human well-being: Synthesis. Mil-
lenium Ecosystem Assessment, Washington, DC
Mieterschutzbund Berlin e. V., (ed) (n.d.) Heizperiode Beginnt Bald.
https:// www. miete rschu tzbund- berlin. de/ news- lesen/ items/
heizp eriode. html.Accessed 8 Jul 2020
Monsi M (2004) On the factor light in plant communities and its
importance for matter production. Ann Bot 95:549–567.
https:// doi. org/ 10. 1093/ aob/ mci052
Nicholls N, Skinner C, Loughnan M, Tapper N (2008) A simple
heat alert system for Melbourne, Australia. Int J Biometeorol
52:375–384. https:// doi. org/ 10. 1007/ s00484- 007- 0132-5
Nilsson M, Forssén J (2013) Novel solutions for quieter and greener
cities. Holistic and Sustainable Abatement of Noise by optimized
combinations of Natural and Artificial means (HOSANNA)
Ottelé M (2011) The green building envelope: Vertical greening. Doc-
toral Thesis, Technische Universiteit Delft
Ottelé M, van Bohemen HD, Fraaij ALA (2010) Quantifying the depo-
sition of particulate matter on climber vegetation on living walls.
Ecol Eng 36:154–162. https:// doi. org/ 10. 1016/j. ecole ng. 2009.
02. 007
Pearlmutter D, Pucher B, Calheiros CSC etal (2021) Closing water
cycles in the built environment through nature-based solutions:
the contribution of vertical greening systems and green roofs.
Water 13:2165. https:// doi. org/ 10. 3390/ w1316 2165
Pérez G, Coma J, Barreneche C etal (2016) Acoustic insulation capac-
ity of Vertical Greenery Systems for buildings. Appl Acous
110:218–226. https:// doi. org/ 10. 1016/j. apaco ust. 2016. 03. 040
Pérez G, Rincón L, Vila A etal (2011) Green vertical systems for
buildings as passive systems for energy savings. Appl Energy
88:4854–4859. https:// doi. org/ 10. 1016/j. apene rgy. 2011. 06. 032
Pérez-Urrestarazu L, Blasco-Romero A, Fernández-Cañero R (2017)
Media and social impact valuation of a living wall: the case
study of the Sagrado Corazon hospital in Seville (Spain). Urban
Urban Green 24:141–148. https:// doi. org/ 10. 1016/j. ufug. 2017.
04. 002
Perini K, Ottelé M, Haas EM, Raiteri R (2013) Vertical greening sys-
tems, a process tree for green façades and living walls. Urban
Ecosyst 16:265–277. https:// doi. org/ 10. 1007/ s11252- 012- 0262-3
Perini K, Rosasco P (2013) Cost–benefit analysis for green façades and
living wall systems. Build Environ 70:110–121. https:// doi. org/
10. 1016/j. build env. 2013. 08. 012
Pfadenhauer JS, Klötzli FA (2014) Vegetation der Erde. Springer, Ber-
lin Heidelberg, Berlin, Heidelberg
Preiss J (2013) Leitfaden Fassadenbegrünung. ÖkoKauf Wien, AG 25,
Grün- und Freiräume
Pugh TAM, MacKenzie AR, Whyatt JD, Hewitt CN (2012) Effective-
ness of green infrastructure for improvement of air quality in
urban street canyons. Environ Sci Technol 46:7692–7699. https://
doi. org/ 10. 1021/ es300 826w
1429Urban Ecosystems (2022) 25:1417–1430
1 3
Radić M, Brković Dodig M, Auer T (2019) Green facades and living
walls—a review establishing the classification of construction
types and mapping the benefits. Sustainability 11:4579. https://
doi. org/ 10. 3390/ su111 74579
Reid C, Clougherty J, Shmool J, Kubzansky L (2017) Is all urban green
space the same? A comparison of the health benefits of trees and
grass in New York City. Int J Environ Res Public Health 14:1411.
https:// doi. org/ 10. 3390/ ijerp h1411 1411
Reznik G, Schmidt E (2009) Immissionsminderung durch Pflanzen –
Abscheidung und Abwaschung von Feinstaub an Efeu. Gefahrst
- Reinhalt Luft 69:6
Robine J-M, Cheung SLK, Le Roy S etal (2008) Death toll exceeded
70,000 in Europe during the summer of 2003. C R Biol 331:171–
178. https:// doi. org/ 10. 1016/j. crvi. 2007. 12. 001
Russo A, Cirella G (2018) Modern compact cities: How much greenery
do we need? Int J Environ Res Public Health 15:2180. https:// doi.
org/ 10. 3390/ ijerp h1510 2180
SenS (2011) Flächennutzung und Stadtstruktur: Dokumentation der
Kartiereinheiten und Aktualisierung des Datenbestandes 2010.
Senatsverwaltung für Stadtentwicklung Berlin
SenStadtUm (2015a) 09.01 Umweltgerechtigkeit (Ausgabe 2015a).
Senatsverwaltung für Stadtentwicklung und Umwelt Berlin,
Berlin
SenStadtUm (2011) Stadtentwicklungsplan Klima – Urbane Lebens-
qualität im Klimawandel sichern. Senatsverwaltung für Stadtent-
wicklung und Umwelt Berlin 84
SenStadtUm (2015b) Umweltgerechtigkeit: Kernindikator Luftbelas-
tung (Umweltatlas)
SenSW (2015) Umweltatlas Berlin - [Umweltgerechtigkeit: Integrierte
Mehrfachbelastung Umwelt und Soziale Problematik
SenSW (2017) 07.05 Strategische Lärmkarten (Ausgabe 2017)
SenSW (2020) Grünanlagenbestand Berlin (einschließlich der öffen-
tlichen Spielplätze)
SenSW (2019) Einwohnerdichte 2018 (Umweltatlas)
SenSW (2018) Ortsteile von Berlin
SenUVK (2019) Basisbericht Umweltgerechtigkeit. Senatsverwaltung
für Umwelt, Verkehr und Klimaschutz Berlin
Steffen W, Richardson K, Rockstrom J etal (2015) Planetary bounda-
ries: Guiding human development on a changing planet. Science
347:1259855–1259855. https:// doi. org/ 10. 1126 / scien ce. 12598 55
Šuklje T, Medved S, Arkar C (2016) On detailed thermal response
modeling of vertical greenery systems as cooling measure for
buildings and cities in summer conditions. Energy 115:1055–
1068. https:// doi. org/ 10. 1016/j. energy. 2016. 08. 095
Tost H, Reichert M, Braun U etal (2019) Neural correlates of individ-
ual differences in affective benefit of real-life urban green space
exposure. Nat Neurosci 22:1389–1393. https:// doi. org/ 10. 1038/
s41593- 019- 0451-y
UBA (2009) Umwelt, Gesundheit und soziale Lage - Studien zur sozi-
alen Ungleichheit gesundheitsrelevanter Umweltbelastungen in
Deutschland. Umweltbundesamt
UBA (ed) (2019) Luftqualität 2018. Vorläufige Auswertung. 28
UN DESA (2019) The World’s Cities in 2018 - Data Booklet. United
Nations, Department of Economic and Social Affairs, Population
Division, New York
UNDP (2014) Environmental Justice - Comparative experiences in
legal empowerment. United Nations Development Programme,
New York
UNEP (2019) Global Environment Outlook – GEO-6: Summary for
Policymakers. United Nations Environmental Programme
Urban A, Kyselý J (2014) Comparison of UTCI with other thermal indi-
ces in the assessment of heat and cold effects on cardiovascular
mortality in the Czech Republic. Int J Environ Res Public Health
11:952–967. https:// doi. org/ 10. 3390/ ijerp h1101 00952
van Kempen E, Babisch W (2012) The quantitative relationship
between road traffic noise and hypertension: a meta-analysis. J
Hypertens 30:1075–1086. https:// doi. org/ 10. 1097/ HJH. 0b013
e3283 52ac54
Van Renterghem T, Botteldooren D, Verheyen K (2012) Road traffic
noise shielding by vegetation belts of limited depth. J Sound Vib
331:2404–2425. https:// doi. org/ 10. 1016/j. jsv. 2012. 01. 006
Van Renterghem T, Hornikx M, Forssen J, Botteldooren D (2013)
The potential of building envelope greening to achieve quiet-
ness. Build Environ 61:34–44. https:// doi. org/ 10. 1016/j. build
env. 2012. 12. 001
Vardoulakis S, Fisher BEA, Pericleous K, Gonzalez-Flesca N (2003)
Modelling air quality in street canyons: a review. Atmos Environ
37:155–182. https:// doi. org/ 10. 1016/ S1352- 2310(02) 00857-9
WHO (2011) Burden of disease from environmental noise: quantifica-
tion of healthy life years lost in Europe. World Health Organiza-
tion, Regional Office for Europe, Copenhagen
WHO (2018a) Environmental noise guidelines for the European
Region. World Health Organisation Regional Office for Europe,
Copenhagen
WHO (2018b) Ambient (outdoor) air pollution. In: World Health
Organization. https:// www. who. int/ news- room/ fact- sheets/ detail/
ambie nt- (outdo or)- air- quali ty- and- health
WHO (1999) Guidelines for community noise. World Health Organi-
zation, Geneva
WHO (2009) Night noise guidelines for Europe. World Health Organi-
zation Europe, Copenhagen, Denmark
WHO (2018c) WHO housing and health guidelines. World Health
Organization, Geneva
Wong NH, Kwang Tan AY, Chen Y etal (2010a) Thermal evaluation
of vertical greenery systems for building walls. Build Environ
45:663–672. https:// doi. org/ 10. 1016/j. build env. 2009. 08. 005
Wong NH, Kwang Tan AY, Tan PY etal (2010b) Acoustics evaluation
of vertical greenery systems for building walls. Build Environ
45:411–420. https:// doi. org/ 10. 1016/j. build env. 2009. 06. 017
Wüstemann H, Kalisch D, Kolbe J (2016) Towards a national indicator
for urban green space provision and environmental inequalities in
Germany: Method and findings. SFB 649, Humboldt-Universität
zu Berlin
Yang H-S, Kang J, Cheal C (2013) Random-incidence absorption and
scattering coefficients of vegetation. Acta Acust United Acust
99:379–388. https:// doi. org/ 10. 3813/ AAA. 918619
1430 Urban Ecosystems (2022) 25:1417–1430
