ArticlePDF Available

Life Cycle Analysis of Green Roof Implemented in a Global South Low-Income Country


Abstract and Figures

Environmental protection becomes a global challenge currently. Green roof is one of the innovative concepts to face this battle. An increase in its use is noticed in urban areas worldwide. But a question arises: what are the environmental consequences of the green roofs’ life cycle? In this paper, the environmental performance of two complete systems of lighter and heavier green roofs implemented in a global south low-income country are analyzed and compared in order to determine the potential impacts of both types of green roof systems. For proposing solutions aiming at reducing environmental loads of green roofs, Life-Cycle Assessment (LCA) approach was used in the present study. For this purpose, the approach consists of the following phases: definition of the objective, life cycle inventory, characterization of impacts, and interpretation of results. LCA calculations were done with the help of OpenLCA software. Results show that, non treated materials and / or imported ones are more environmentally impactful. Hence, it is profitable to reduce the use of cement, gravel, virgin plastics, and soil as well as imported materials whose transport is done by plane. In addition, use of natural fertilizer for amending the growth substrate and water from well for watering the green roof, is also recommended.
Content may be subject to copyright.
*Corresponding author: E-mail:;
British Journal of Environment & Climate Change
7(1): 43-55, 2017; Article no.BJECC.2017.004
ISSN: 2231–4784
SCIENCEDOMAIN international
Life Cycle Analysis of Green Roof Implemented in a
Global South Low-income Country
Dominique Morau
, Tsiorimalala N. Rabarison
and Hery T. Rakotondramiarana
Research Unit Piment, University of La Reunion, 117 Rue du Général Ailleret 97430, Le Tampon,
Reunion, France.
Institute for the Management of Energy (IME), University of Antananarivo, P.O.Box 566,
Antananarivo 101, Madagascar.
Authors’ contributions
This work was carried out in collaboration between all authors. All authors read and approved the final
Article Information
DOI: 10.9734/BJECC/2017/30796
Received 1
December 2016
Accepted 8
March 2017
Published 30
March 2017
Environmental protection becomes a global challenge currently. Green roof is one of the innovative
concepts to face this battle. An increase in its use is noticed in urban areas worldwide. But a
question arises: what are the environmental consequences of the green roofs’ life cycle? In this
paper, the environmental performance of two complete systems of lighter and heavier green roofs
implemented in a global south low-income country are analyzed and compared in order to
determine the potential impacts of both types of green roof systems. For proposing solutions
aiming at reducing environmental loads of green roofs, Life-Cycle Assessment (LCA) approach
was used in the present study. For this purpose, the approach consists of the following phases:
definition of the objective, life cycle inventory, characterization of impacts, and interpretation of
results. LCA calculations were done with the help of OpenLCA software. Results show that, non
treated materials and / or imported ones are more environmentally impactful. Hence, it is profitable
to reduce the use of cement, gravel, virgin plastics, and soil as well as imported materials whose
transport is done by plane. In addition, use of natural fertilizer for amending the growth substrate
and water from well for watering the green roof, is also recommended.
Keywords: Green roof; impact; climate change; Life-Cycle Assessment; OpenLCA.
Original Research Article
Morau et al.; BJECC, 7(1): 43-55, 2017; Article no.BJECC.2017.004
A green roof is a roof supporting a layer of soil in
which grow vegetations. It is a green solution in
urban areas [1]. Existing for centuries before
Christ, this concept is used in many countries
such as Canada, China, United States of
America and some European countries. It has
evolved and brings a lot of benefits: allowing
energy savings for building heating in winter and
decreasing the indoor temperature in summer [2,
3], protecting and extending the life of the roof
membrane against extreme temperatures and
their fluctuations [4]. Its use also improves sound
insulation [5]; a 12 cm thick canopy layer reduces
noises by about 40 to 50dB. Moreover, green
roofs reduce the urban heat island effect as well.
Works of [6] show a mitigating urban heat island
by green roofs compared to roofs that are made
of metal, asphalt or brick. The use of green roofs
significantly contributes to the retention and
purification of rainwater [7,8]. It also allows a
capture of carbon dioxide and an improved air
quality. Besides, a sharp increase of human
activities on the exploitation of natural resources,
manufacturing materials, transportation and
urban construction, can be noticed. The amount
of newly discovered resources continues to
decline due to their limited and non-renewable
characters [9]. Urban buildings are increasing
and creating adverse effects on the environment
[10]. Green roofs can be adopted to overcome
these problems. Particularly regarding
Madagascar, this big island is in a critical
situation from an environmental perspective. The
aforementioned benefits of green roof can
contribute to reducing pollution problems in
urban areas of Madagascar. However, it is
essential to know the consequences of its
implementation and usage.
Life-Cycle Assessment (LCA) increasingly
becomes indispensable for having more
environmentally friendly design of buildings as
reported by review papers [11,12]. Several
studies on the LCA of green roofs are currently
available in the literature. The first two works
implementing LCA methods were conducted by
Saiz et al. [13] and by Kosareo and Ries [14] for
showing the environmental benefits provided by
green roofs in comparison with that related to
conventional roofs. The former, who totally
neglected the disposal phase of green roofs,
found that cumulative annual energy savings
caused by replacing the conventional flat roof
with a green roof, allows reducing environmental
impacts by between 1.0 and 5.3%. On the other
hand, the latter issued that though energy
savings due to green roof’s lower thermal
conductivity are relatively modest with respect to
the overall building energy use, it is significant for
environmental impact over the life cycle of the
building. Peri et al. [15], while applying LCA to
extensive green roof, focused their attention on
the disposal of substrate and on the impacts of
fertilizers used during the operational phase,
which seem to play an important role in the
whole LCA balance. Besides, Tselekis [16]
highlighted the potential energy savings and
environmental benefits due to the use of green
roofs by comparing construction costs and taking
as references the conventional insulated and
non-insulated roofing systems. Hong et al. [17]
applied 16 improvement scenarios based on
green roof systems in combination with energy-
saving measures for various weather conditions
in South Korea; some of these scenarios were
proven to be cost-effective. Blackhurst et al. [18]
used LCA to assess the widespread installation
of green roofs in a typical urban mixed-use
neighborhood by taking into account the market
prices of materials, construction, energy
conservation, storm-water management, and
greenhouse gas (GHG) emission reductions;
results reveal green roofs are currently not cost
effective on a private cost basis, but multifamily
and commercial building green roofs are
competitive when social benefits are included.
In addition, a certain number of LCA were carried
out to evaluate the environmental impacts of
various green roof constituent materials. For
instance, while focusing their LCA work on
polymers whose manufacturing process causes
emission of harmful elements such as NO
, SO
and PM10 into air, Bianchini and Hewage [19]
reported that the aforementioned air pollution can
be balanced by the green roof’s pollution removal
capacity in 13-32 years. However, they
recommended that low density polyethylene and
polypropylene have to be replaced in the green
roof component materials as their manufacturing
process has many other negative impacts to the
environment than air pollution. Rivela et al. [20],
while applying LCA methods on different green
roof constituent materials, found that the support
layer which is made of concrete slab is the most
impactful in all impact categories with the
exception of the ozone layer depletion category;
the most important impact contribution being due
to thermal insulation made of concrete tile with
extruded polystyrene and to felt wick irrigation
system. Moreover, it is worth noting the work of
Molineux et al. [21] though the utilized method
Morau et al.; BJECC, 7(1): 43-55, 2017; Article no.BJECC.2017.004
was not exactly LCA, as they environmentally
characterized four recycled materials that have
been manufactured into useful substrates for use
on extensive green roofs. While choosing the
crushed red brick as an industry standard
substrate control, three alternative pellets made
from: clay- sewage sludge - fly ash mixture,
recycled newspapers’ ash, and carbonated
limestone. Results revealed that these alternative
substrates have great potential in the green roof
market as they are as good, if not better, than the
industry standard, both economically and
Additionally, Chenani et al. [22] implemented
LCA to two types of extensive green roof for
determining the potential environmental impacts
of different layers composing these green roofs.
Their results highlighted that the water retention,
drainage and substrate layers contained the
most negative impactful components. Hence,
they recommended the design of simple green
roof systems whenever feasible as well as the
use of recycled and local materials rather than
virgin ones and those requiring long distance
transports; use of compost on green roof is also
recommendable as composting organic wastes
seems better than landfill disposal; anyway, the
use of Rockwool, virgin HIPS (High-Impact
PolyStyrene) and expanded clay should be
avoided. Rincón et al. [23] assessed, the
environmental impact and the benefits of using
recycled rubber crumbs from out use tires as a
drainage layer in extensive green roofs, with the
help of LCA in which performances of green
roofs versus conventional ones were compared
while considering the production, construction,
operational, and disposal phases of roofing
systems. It was concluded that the studied
recycled rubber is environmentally friendly
constructive material that should be
recommended for use in buildings. Gargari et al.
[24] focused their LCA work on the green roof
soil for assessing the relevance of different
growing medium types on the environmental
impact of a green roof. It was concluded that
adopting a proper design of the growing medium
soil by taking into account all maintenance
operations is crucial for a good green roof
design. For that purpose, more complete
information (such as thermal and water retention
properties) about the growing medium available
on the market are desirable.
Lamnatou and Chemisana [25] undertook LCA to
evaluate environmental impact of a Photovoltaic
(PV)-green roof along with other roof
configurations: PV-gravel, green (extensive and
intensive), gravel. While material manufacturing,
material transportation, use/maintenance and
disposal phases being considered in the LCA,
the results revealed that material manufacturing
is the most energy-demand phase for all the
studied roofs and the additional environmental
impact characterizing the PV-green system in
comparison with the PV-gravel one can be
balanced on a long-term basis. Then, Lamnatou
and Chemisana [26] could determine the critical
point after which PV-green roof becomes more
eco-friendly than the other PV roofs by means of
ReCiPe methodologies [27,28].
As LCA software tools, commercial products,
especially SimaPro [29], are the most used for
the aforementioned LCA studies [13,14,19,23,
24]. As for the present work, environmental
impacts of extensive and intensive green roofs
located in a low-income country were assessed
according to ISO 14040 [30] and ISO 14044 [31]
standards. More precisely, special attention was
paid on the impact of material transportation as
the building location is in Antananarivo
Madagascar. For that purpose, Ecoinvent v3.1
database [32] was used as database tool
while OpenLCA [33] which is open source
software freely available online was utilized as
LCA tool.
Hence, this work aims at providing potential
solutions for improving the environmental
features of the green roof design and the
manufacturing of materials used in its various
component layers by using free LCA tools.
That should enable to identify the best
implementation scenario among various possible
It is worth reminding that extensive green roof is
lightweight while intensive one is a heavyweight
version. From the bottom to the top layer, green
roofs whose LCA is carried out in this study are
assumed to be made of: a concrete, metallic or
wooden structure for supporting all the other
layers of the green roof, an impermeable
membrane (synthetic rubber), an anti-root
protection (polyethylene), a layer of draining and
filtering (polyethylene), a growth substrate layer
(soil and fertilizer) and a canopy layer (grass,
sedum, shrub). Though polyethylene is among
materials that should be replaced according to
recommendations formulated by [19], it was used
in the present study as there is no low cost
replacement material available in the market on
the basis of the authors’ knowledge.
Morau et al.; BJECC, 7(1): 43-55, 2017; Article no.BJECC.2017.004
LCA is a systemic multi-criteria environmental
approach. It only handles environmental impact
of a product and ignores financial, political or
other aspects. It consists of the following steps:
1) definition of the aim and scope of the study, 2)
life cycle inventory, 3) characterization of
impacts, and 4) interpretation of results [30]. It is
based on the inventory of inputs (for example,
raw materials, transport, process of energy
conversion for the manufacturing and production
of the studied product) and outputs (for example,
emission of substances in soil, in water and in
air). Hence, the potential impacts of each
constituent layer of both aforementioned green
roof types are evaluated and compared using
this approach.
2.1 Aim and Scope of the Conducted LCA
The objective of the conducted LCA is to identify
adverse effects of various constituent layers of a
unit surface of green roof that is located in
Antananarivo Madagascar, to the environment,
human health and resource use. Then, solutions
and remedies are especially proposed for
mitigating these adverse impacts.
The functional unit adopted in this study is "the
construction, the transmission and the use of 1
of green roof for a period of one year, five
years and ten years". A priori we have two types
of green roof having a large difference of
properties in terms of the amount of used
products; the study of both cases allows a
comparison and provides insights that help us
either to improve green roof implementation or at
least to have information for finding which kind of
green roof is more convenient.
With respect to the system boundary, while
mounting and end-of-life phases of the green
roof being excluded, the following ones are
included in the present study: manufacture and
transport of various layers as well as the use of
green roofs. In background, we have: the
extraction of raw materials, energy conversion
and supply, and waste production during the
manufacture of various green roof layers. These
data are already included in our database. Fig. 1
depicts the lifecycle process of green roofs and
the system boundary.
The characterization methodology of impacts we
have used in the simulation is the CML Baseline
method, which is developed by the Institute of
Environmental Sciences (CML) of the University
of Leiden in Netherland, in the OpenLCA
software [33]. This modeling method
corresponds to the first order effects: quantifiable
and relatively straightforward, thus with small
uncertainty but little talking [34].
Fig. 1. Lifecycle process of green roofs and the system boundary
Morau et al.; BJECC, 7(1): 43-55, 2017; Article no.BJECC.2017.004
2.2 Life Cycle Inventory
As being mentioned previously, OpenLCA
software [33] was used to achieve all simulation
steps. All used data are identified from different
companies and experts while referring to the
green roof design guidelines that are proposed
by Peck and Kuhn [35] which shows the amount
of materials used in the design of green roofs.
Ecoinvent (version 3.1) database [32] from which
resources come is adjoined into this software.
For carrying simulations, green roof was
assumed to be constituted by some layers as
illustrated in Fig. 2. For the characteristics of
these different layers in the scenarios, we used
data from [36].
Fig. 2. Various layers constituting a green
2.2.1 Extensive green roof scenario Canopy layer
The canopy layer is the most essential part of the
green roof. While the adopted support being
lighter as can be seen in further subsection, the
selected vegetation for this kind of roof is
herbaceous, more precisely grass, as it is very
variable in quantity and grows over time. For
this study, a unit area of the canopy layer is
made of about 1 kg of grass having a thickness
of 0.02 m. Growth substrate layer
The growth substrate layer is also essential for
the green roof as it serves the nutrition of
vegetation and plays an important role in
managing storm water. For this first type of green
roof, the substrate is made of soil that is mixed
with compost in the ratio of 100 kg and 25 kg
respectively, while having a thickness of 0.15 m. Protection layer
The protection layer is composed of two plastic
materials. The first one is anti root barrier made
of high density polyethylene: 0.76 kg of weight
and 0.0008 m of thickness. This layer is needed
to prevent root penetration into the support. The
other one is a layer of drainage and filtration
consisting of virgin polystyrene: 0.68 kg of weight
and 0.008 m of thickness. The filter is used to
filter fine particles from the substrate while the
drainage layer which looks like an egg box allows
the free flow of water. Support layer
Pine wood was selected as material of the
support layer which is vital as it supports all the
above mentioned different layers of the green
roof; it weighs 25 kg (per unit surface) and is
0.15 m thick. Table 1 lists the transport of
materials for extensive green roof.
Maintenance items on the functional unit during
the roof-use are watering and addition of
substrate on the canopy and soil layers. In terms
of resources, 20 kg of fertilizer and 96 kg of
water per unit area of the green roof should be
added. With the help of database, the following
process was considered "Tap water production
underground water without treatment - Rest-of-
the-World (RoW)" and "Field application of
compost-RoW". The quantities of required inputs
are calculated according to the use period of the
considered product.
Table 1. Transport of extensive green roof materials
Layer Transport, freight,
lorry 3.5-7.5
metric ton,
Transport, freight,
lorry 3.5-7.5 metric
ton, EURO3-RoW*
Transport, freight,
light commercial
freight, sea,
Canopy - - 30 km -
Substrate - - 20 km -
Protection 225 km 365 km 20 km 8938 km
Support - 168 km 20 km -
*Abbreviations being region codes used by ecoinvent for indicating the geography such that:
Global (GLO), Europe (RER), the Rest-of-the-world (RoW)
Morau et al.; BJECC, 7(1): 43-55, 2017; Article no.BJECC.2017.004
2.2.2 Intensive green roof scenario
The component materials of intensive green roof
are listed in Table 2. It was assumed that only
support and protection layers change during
For the support layer, cement undergoes two
types of transport: one by truck and another one
by commercial car, over distances of 190 km and
20 km respectively. Additionally, we made the
assumption that steel comes from South Africa,
by 4 types of transportation means: rail, sea,
truck and commercial car over distances of 210,
2617.92, 365 and 20 km respectively. Gravels
are transported by road on a commercial
transport route over 20 km.
With respect to the protection layer, after a
commercial car transport of about 20 km to the
airport, it is conveyed by aerial transport from
Europe to Antananarivo of 5655 km of distance,
and then it is again transported by commercial
car over a distance of 50 km.
In addition, 150 kg of fertilizer and 730 L of water
are added to the green roof annually. The
process data that are taken into account in the
present study are related to the production of
cement, steel, gravel, polyethylene, polystyrene,
wool, cracked tile, fertilizer, and bush.
2.3 Impact Assessment
This step converts inventory data in indicators
that characterize the potential effects on human
health and on the environment of the considered
product during its life cycle [28]. We used the
latest version of CML Baseline method. It
presents ten categories of environmental
impacts, but we only present 3 that are of interest
and relevant to the case of Madagascar as
shown by Table 3.
Table 2. Component materials of intensive green roof
Layer Product Material Weight
) Thickness
Support Concrete
Anti-root barrier
Recycled LDPE (Low
Density PolyEthylene) 0.175 0.0002
Drainage and
filtration Recycled HIPS (High-
Impact PolyStyrene) 1.252 0.05
Water reserve Hydrophilic mineral wool 6 (dry)
46 (saturated) 0.0275
Substrate Mixture of recycled
soil and organic
Crushed tile
Poultry manure 200
50 0.40
Canopy Vegetation Low growth bushes 10 1
Table 3. Descriptions of selected impact categories
Category of impact Indicator Unit Description
Climate change
GWP100 (Global
Warming Potential) Kg CO
eq. The product’s impact on
global warming over 100
Depletion of abiotic
Fossil fuels MJ Characterization of
emissions of greenhouse
gases in the air.
Human toxicity HTP inf. (Human
toxicity Potential) Kg 1.4-
The potential effect on
humans of toxic
substances emitted into
the air, water and soil.
Morau et al.; BJECC, 7(1): 43-55, 2017; Article no.BJECC.2017.004
We chose the Global Warming Potential (GWP)
with a 100 year time horizon as it is the most
widely used indicator. It represents the duration
of human life and was selected in the Kyoto
Protocol Article 5-3. We also need a long time
span to see the change caused by global
warming (for example: increase of sea levels).
3.1 Phase 1: Production of Various Green
Roof Constituent Layers
Simulation results obtained from OpenLCA [33]
are presented in Table 4 which compares
production impacts of various constituent layers
of both considered green roof types.
Compared to wood use, cement production
impacts 53 kg CO
equivalent more while steel
manufacturing causes only 5.3 kg CO
equivalent of additional impacts. In terms of
resource consumption, cement production
consumes 15 times more compared to steel
fabrication. On human toxicity, cement
production is always the most impacting with a
value of 5.288 kg 1.4-dichlorobenzene
equivalent. Generally, impacting substances are
those that are released during various stages of
production or transport rather than those
contained in the product unless they are toxic
ones. Cement is produced by combustion of
limestone and other additives at very high
temperatures. Such combustion rejects flying
ashes and fine mineral particles which can be
carcinogenic to humans [37].
Table 4. Comparison of production impacts of both green roof types’ layers
Layer Category of impact* Climate
change -
(Kg CO
of abiotic
Human toxicity -
HTP inf.**
(Kg 1.4-
dichlorobenzene eq.)
Support Woodwool production-RoW* -15.861 11.087 0.368
Gravel production, crushed-RoW 0.657 8.026 0.631
Cement production, pozzolana
and fly ash 11-35%, non-US** 89.148 318.375 7.931
Steel production, low-alloyed, hot
rolled-RoW* 2.905 36.949 2.777
Substrate Field Application of compost-
RoW* 19.982 260.66 10.479
Land already in use, arable land-
GLO* 40.625 84.084 10.372
Field application of poultry
manure –RoW* 4.136 257.329 13.172
Concrete roof tile production-
RoW 59.7 357.748 17.224
Polyethylene production, linear
high density, granulate-RER* 1.494 50.589 0.064
Polyethylene production, low
density, granulate-RER* 0.333 10.303 0.018
Polystyrene foam slab
production, 100% recycled-RER* 0.461 6.477 0.142
Polystyrene, high impact –RER* 2.307 51.446 0.215
Woodwool production-RER* -3.45 5.929 0.266
Canopy Grass production, permanent
grassland, organic, extensive-
-2.746 1.081 1.081
Grass production, organic,
intensive –RoW* -6.277 2.471 0.029
*Geographical codes used by ecoinvent [32]: GLO (Global), RER (Europe), RoW (Rest-of-the-world);
** GWP100 (Global Warming Potential), HTP inf. (Human Toxicity Potential), US (United States)
Morau et al.; BJECC, 7(1): 43-55, 2017; Article no.BJECC.2017.004
For the protection layer: materials that are used
for extensive green roof are more impacting
compared to those related to intensive green
roof. Indeed, high density materials which require
more resources are employed for extensive
green roof. These materials are more impacting
due to their impurities which contain noxious and
polluting substances. The use of recycled
materials and low density has less impact. For
example, polystyrene which comes from
benzene hydrocarbon is toxic if inhaled.
However, the recycled polystyrene is less toxic
as more than 60% of the aforementioned
pollutants are already eliminated in the recycling
With regard to the substrate layer: the choice of
substrate components is an important part in the
implementation of a green roof. It can be noted in
the inventory that the substrate amount of
intensive green roof is twice that of the extensive
green roof. Then in the climate change section,
the use of crushed tile is beneficial as this
material is recycled; it enables to halve the
amount of the required substrate, for example.
Nonetheless, the use of soil is more
advantageous in terms of resource consumption.
This is due to energy consumption related to the
tile crushing. For the choice of fertilizers, here the
use of the material for intensive green roof is
twice that for extensive green roof. However, the
global warming category result shows that the
use of compost is 5 times more impacting than
the use of manure from poultry. For resource
depletion, compost consumes twice more
resource for identical amounts of material
contained in both kinds of manures. All this
comes from the production, transportation and
spreading of compost which requires the use of
mechanical and motorized vehicles which are
major consumers of resources and are sources
of pollutant emissions (carbon dioxide and fine
particles) in large quantities. Compost is not
intended for use on green roofs initially, but it
enables to avoid landfill disposal [22]. Thus, it is
better to use natural products requiring no
treatment as fertilizer.
With respect to canopy layer: for all impact
categories, we can see from these results that
the environmental impacts are proportional to the
amount of used vegetation for the roof type.
Therefore, the intensive green roof presents
more impacts than the extensive one. Inversely,
this latter has negative effects on climate
change, which are advantages.
3.2 Phase 2: Transportation of Materials
to the Building Site
Fig. 3 presents the comparison of material
transportation impacts for both green roof types.
Fig. 3. Comparison of material transportation impacts for both green roof types
Morau et al.; BJECC, 7(1): 43-55, 2017; Article no.BJECC.2017.004
For all categories of impact, transportation of the
intensive green roof support layer causes 8 times
greater impact than that related to the extensive
green roof one. For intensive green roof,
transportation of various materials is done by 3
types of transport: aerial, maritime and terrestrial,
which not only involve very high value of climate
change through emission of greenhouse gases
but also consume fossil resources and release
environmental pollutants. Indeed, these
transportations emit into the atmosphere
substances such as nitrogen oxide (NO) and
sulfur dioxide (SO
) with different emission rates.
The impact of transportation is here dominated
by maritime transport. To transport the protection
layer, that related to intensive green roof is more
impacting as aerial transport is used.
Emissions from the abovementioned
transportations contribute to increasing the
concentration of greenhouse gases in the
atmosphere. They are responsible for the
retention of heat as well as the diffraction of
radiation contributing to climate change. On
resource depletion, fuel consumption is more or
less proportional to the traveled distance. With
regard to human toxicity, the aircraft causes
higher emissions compared to other types of
transport means. Indeed, today's aircraft release
high amounts of CO in the troposphere and
stratosphere, which is hazardous to human
The travelled distances for the transportation of
the respective substrate layers of both green roof
types are identical but the amounts of
transported materials are different, as
transportation of the substrate layer for the
intensive green roof is twice more impacting, that
is, the impact is double for each impact category,
than that related to the extensive one.
The transportation of the canopy layer is done by
trucks. The impact is dependent on the load and
the distance; the heavier is the load, the more
pollutant is the transportation.
3.3 Phase 3: Use Phase
While the previous subsection results show that
the use of intensive green roof is environmentally
more impactful than the extensive green roof
because of the difference of used materials and
their amounts, the present subsection aims at
scrutinizing the resource consumption according
to the use patterns of both roof types in order to
choose materials that allow saving resource.
As can be seen once more from Fig. 4, for every
category of impact, intensive green roof is
environmentally more impactful than the
extensive green roof for all considered use phase
lifetime span. Besides, impact magnitude on
climate change of intensive green roof for
5-year use phase is almost equivalent to that
related to 10-year use phase of extensive green
As being outlined previously, maintenance
process mainly consists of adding fertilizer and
watering periodically. The use of fertilizer from
poultry is more advantageous over the compost
use as fertilizer made of chicken droppings is
produced on site without biological treatment
which can lead to high energy consumption.
Moreover, it also is convenient to water the green
roof canopy with well water which can be
pumped, for example, by photovoltaic devices.
3.4 Suggestion of Some Solutions
In this subsection, some improvement solutions
for mitigating potential impacts are suggested.
Some information allowing the choice of
materials and means of transport to be used are
presented as well.
To have a much lighter structure, a steel
structure whose impact has already been studied
by Olmez et al. [38] can be used instead of a
concrete structure. However, it is better to
choose wood for its ability to store CO
[39]. The
fact of using less plastic materials reduces the
impact of the protection layer. It is beneficial to
use manually crushed tile mixed with chicken
droppings for the substrate layer. Whatever the
vegetation types, the canopy layer is always of
interest through its capacity of CO
storage and
dust collection.
Several means of transport were presented
during the inventory. Air transport is dominant
overall impact categories as it emits GHG and
pollutants up to 8 times greater than maritime
transport for the same quantity of carried loads.
Besides, the amount of GHG emission related to
intensive green roof protection layer is here 8
times greater than that of extensive green roof
one. Although transportation has been included
in previous studies (Kosareo and Ries [14]), its
total environmental impact has not been
quantified explicitly. In the present study, it has a
very important part of impacts. As optimization
solution, production in situ of materials is
Morau et al.; BJECC, 7(1): 43-55, 2017; Article no.BJECC.2017.004
Fig. 4. Comparison of impacts during use phases of both green roof types
Adding the growth substrate and watering are
always crucial when using green roofs.
Therefore, their impacts are also to be
considered. According to the above presented
results, the impact of the use phase of intensive
green roof is more important than that of the
extensive green roof. Additionally, the poultry
manure remains the best fertilizer as the quantity
of added elements in intensive green roof is
more than those related to the extensive green
roof. One can assert that the impact of each
material depends on its amount, its transport and
especially of its characteristics. According to
Fertilizers Europe and UNIFA (Union des
industries de la fertilisation), finding an
alternative to traditional fertilizer is important as
composting waste products would be profitable.
Hence, there is a sensitization for the use of the
ammonitrate (an ammonium nitrate-based
mineral fertilizer) that could reduce the carbon
footprint by up to 25% [40]. And finally, the use of
well water rather than tap water is advantageous
for saving resource and energy.
The environmental performance of both
lightweight and heavyweight green roof systems
was analyzed to determine their potential
environmental impacts. For that purpose, the
respective impacts of different materials,
transport and use of layers constituting the green
roofs were calculated using free LCA tools.
Based on the obtained results, it is possible to
develop simple green roof systems using as
less artificial materials as possible. Under the
adopted assumptions in the present study,
recycled products should be used instead of
natural ones.
With respect to materials, it is better to choose
lightweight materials from the support layer to the
canopy layer. Improvements of the most
impactful materials such as those used for the
protection stratum and the substrate layer should
be considered.
As far as transportation is concerned, it is
reasonable to make maximum use of local
products in order to avoid the high environmental
impacts of international transport.
With regard to energy and resource consumption
during the use phase of green roof: it can be
asserted from the obtained comparison results
that there is a huge difference between using
compost and chicken manure as fertilizer in the
substrate layer; it is more beneficial to utilize
chicken manure. Moreover, the use of well water
is also recommended for watering.
Morau et al.; BJECC, 7(1): 43-55, 2017; Article no.BJECC.2017.004
The authors of this work are grateful to
Bienvenue Raheliarilalao for her assistance on
the use of LCA tools.
Authors have declared that no competing
interests exist.
1. Catalano C, Marcenò C, Laudicina VA,
Guarino R. Thirty years unmanaged green
roofs: Ecological research and design
implications. Landscape Urban Plan.
DOI: 10.1016/j.landurbplan.2016.01.003
2. Gao T, Shen L, Shen M, Chen F, Liu L,
Gao L. Analysis on differences of carbon
dioxide emission from cement production
and their major determinants. J Clean
Prod. 2015;103:16070.
DOI: 10.1016/j.jclepro.2014.11.026
3. Coma J, Pérez G, So C, Castell A,
Cabeza LF. Thermal assessment of
extensive green roofs as passive tool for
energy savings in buildings. Renew Energ.
DOI: 10.1016/j.renene.2015.07.074
4. Rakotondramiarana HT, Ranaivoarisoa TF,
Morau D. Dynamic simulation of the green
roofs impact on building energy
performance, case study of Antananarivo,
Madagascar. Buildings. 2015;5(2):497-20.
DOI: 10.3390/buildings5020497
5. Anonymous. Etude pour lafinition d’une
démarche de développement des toitures
végétalisées. Ernst & Young. Nice Côte
d'Azur, France; 2009.
(Accessed 15 May 2016)
6. Razzaghmanesh M, Beecham S, Salemi T.
The role of green roofs in mitigating Urban
Heat Island effects in the metropolitan area
of Adelaide, South Australia. Urban For
Urban Gree. 2016;15:89102.
DOI: 10.1016/j.ufug.2015.11.013
7. Zhang Q, Miao L, Wang X, Liu D, Zhu L,
Zhou B, Sun J, Liu J. The capacity of
greening roof to reduce stormwater runoff
and pollution. Landscape Urban Plan.
DOI: 10.1016/j.landurbplan.2015.08.017
8. Hashemi SSG, Mahmud HB, Ashraf MA.
Performance of green roofs with respect to
water quality and reduction of energy
consumption in tropics: A review. Renew
Sustain Energy Rev. 2015;52:66979.
DOI: 10.1016/j.rser.2015.07.163
9. Bentley RW. Global oil & gas depletion:
An overview. Energ Policy. 2002;30(3):
DOI: 10.1016/S0301-4215(01)00144-6
10. Yang X, Li Y. The impact of building
density and building height heterogeneity
on average urban albedo and street
surface temperature. Build Environ.
DOI: 10.1016/j.buildenv.2015.03.037
11. Khasreen MM, Banfill PFG, Menzies GF.
Life-cycle assessment and the
environmental impact of buildings: A
review. Sustainability. 2009;1:674–701.
DOI: 10.3390/SU1030674
12. Cabeza LF, Rincón L, Vilariño V, Pérez G,
Castell A. Life Cycle Assessment (LCA)
and life cycle energy analysis (LCEA) of
buildings and the building sector: A review.
Renew Sustain Energy Rev. 2014;29:394–
13. Saiz S, Kennedy C, Bass B, Snail K.
Comparative Life Cycle Assessment of
standard and green roofs. Environ Sci
Technol. 2006;40:4312-6.
DOI: 10.1021/es0517522
14. Kosareo L, Ries R. Comparative
environmental Life Cycle Assessment of
green roofs. Build Environ. 2007;42:2606-
DOI: 10.1016/j.buildenv.2006.06.019
15. Peri G, Traverso M, Finkbeiner M, Rizzo
G. Embedding “substrate” in environmental
assessment of green roofs life cycle:
evidences from an application to the whole
chain in a Mediterranean site. J Clean
Prod. 2012;35:274-87.
DOI: 10.1016/j.jclepro.2012.05.038
16. Tselekis K. Literature review of the
potential energy savings and retention
water from green roofs in comparison with
conventional one. Environ Clim Technol.
17. Hong TH, Kim JM, Koo CW. LCC and
LCCO2 analysis of green roofs in
elementary schools with energy saving
measures. Energy Build. 2012;45:229-239.
DOI: 10.1016/j.enbuild.2011.11.006
Morau et al.; BJECC, 7(1): 43-55, 2017; Article no.BJECC.2017.004
18. Blackhurst M, Hendrickson C, Matthews H.
Cost-effectiveness of green roofs. J Archit
Eng. ASCE. 2010;136-143.
19. Bianchini F, Hewage K. How "green" are
the green roofs? Lifecycle analysis of
green roof materials. Build Environ.
DOI: 10.1016/j.buildenv.2011.08.019
20. Rivela B, Cuerda I, Olivieri F, Bedoya C,
Neila J. Life Cycle Assessment for
ecodesign of ecological roof made with
Intemper TF ecological water-tank system
[Análisis de Ciclo de Vida para el
ecodiseño del sistema Intemper TF de
cubierta ecológica aljibe]. Mater
Construcc. 2013;63:131-45.
21. Molineux CJ, Fentiman CH, Gange AC.
Characterising alternative recycled waste
materials for use as green roof growing
media in the UK. Ecol Eng. 2009;35:1507
DOI: 10.1016/j.ecoleng.2009.06.010
22. Chenani SB, Lehvävirta S, Häkkinen T.
Life Cycle Assessment of layers of green
roofs, J Clean Prod. 2015;90:153-62.
DOI: 10.1016/J.JCLEPRO.2014.11.070
23. Rincón L, Coma J, Pérez G, Castell A,
Boer D, Cabeza LF, Environmental
performance of recycled rubber as
drainage layer in extensive green roofs: A
comparative life cycle assessment. Build
Environ. 2014;74:22–30.
DOI: 10.1016/j.buildenv.2014.01.001
24. Gargari C, Bibbiani C, Fantozzi F,
Campiotti CA. Environmental impact of
Green roofing: The contribute of a green
roof to the sustainable use of natural
resources in a life cycle approach.
Agriculture and Agricultural Science
Procedia. 2016;8:646–56.
DOI: 10.1016/j.aaspro.2016.02.087
25. Lamnatou Chr, Chemisana D,
Photovoltaic-green roofs: A Life Cycle
Assessment approach with emphasis on
warm months of Mediterranean climate. J
Clean Prod. 2014;72:57-75.
DOI: 10.1016/j.jclepro.2014.03.006
26. Lamnatou Chr, Chemisana D. Evaluation
of photovoltaic-green and other roofing
systems by means of ReCiPe and multiple
life cycle-based environmental indicators.
Build Environ. 2015;93:376-84.
DOI: 10.1016/j.buildenv.2015.06.031
27. Goedkoop M, Heijungs R, Huijbregts M,
De Schryver A, Struijs J, Van Zelm R.
ReCiPe 2008, A life cycle impact
assessment method which comprises
harmonised category indicators at the
midpoint and 39 the endpoint level. 1
Report I: Characterisation, Netherlands:
Ministerie van Volkshuisvesting,
Ruimtelijke Ordening en Milieubeheer;
28. ILCD Handbook: Analysing of existing
Environmental Impact Assessment
methodologies for use in Life Cycle
Assessment. 1
ed. Italy: Joint Research
Centre, TP 270 21027 Ispra (VA); 2010.
(Accessed 24 May 2016)
29. Goedkoop M, Oele M. SimaPro 5.1 User
Manual: Introduction into LCA
methodology and practice with SimaPro
5.1. The Netherlands: PRe´Consultants
B.V.; 2002.
(Accessed 16 April 2016)
30. ISO 14040. Environmental management -
Life Cycle Assessment – principles and
framework. Geneva: International
Organization for Standardization; 2006.
31. ISO 14044. Environmental management -
Life Cycle Assessment –requirements
and guidelines. Geneva: International
Organization for Standardization; 2006.
32. Frischknecht R, Jungbluth N, Althaus H-J,
Doka G, Dones R, Heck T, et al. The
ecoinvent database: Overview and
methodological framework (7pp). Int J Life
Cycle Assess. 2005;10(1):3–9.
DOI: 10.1065/lca2004.10.181.1
33. Ciroth A, ICT for environment in life cycle
applications openLCA new open source
software for life cycle assessment. Int J
Life Cycle Assess. 2007;12(4):209–10.
DOI: 10.1065/lca2007.06.337
34. Acero AP, Rodríguez C, Ciroth A. LCIA-
methods: Impact assessment methods in
Life Cycle Assessment and their impact
categories. Green Delta; 2015.
(Accessed 28 June 2016)
Morau et al.; BJECC, 7(1): 43-55, 2017; Article no.BJECC.2017.004
35. Peck S, Kuhn M. Lignes directrices de
conception des toits verts. Ontario
Association of Architects; 2002. French.
(Accessed 15 June 2016)
36. Van Mechelen C, Dutoit T, Hermy M.
Adapting green roof irrigation practices for
a sustainable future: A review. Sustainable
Cities and Society. 2015;19:7490.
DOI: 10.1016/j.scs.2015.07.007
37. García-Pérez J, López-Abente G, Castelló
A, González-Sánchez M, Fernández-
Navarro P. Cancer mortality in towns in the
vicinity of installations for the production of
cement, lime, plaster, and magnesium
oxide. Chemosphere. 2015;128:10310.
DOI: 10.1016/j.chemosphere.2015.01.020
38. Olmez GM, Dilek FB, Karanfil T, Yetis U.
The environmental impacts of iron and
steel industry: A Life Cycle Assessment
study. J Clean Prod. 2016;130:195–201.
DOI: 10.1016/j.jclepro.2015.09.139
39. Guo Y, Zhao C, Chen X, Li C. CO
and sorbent regeneration performances of
some wood ash materials. Appl Energ.
DOI: 10.1016/j.apenergy.2014.09.086
40. Poidevin G. L'ammonitrate plus efficace et
plus respectueux de l'environnement.
Press conference given by the general
delegate of UNIFA. France, 11 April; 2013.
(Accessed 15 September 2016)
© 2017 Morau et al.; This is an Open Access article distributed under the terms of the Creative Commons Attribution License
(, which permits unrestricted use, distribution, and reproduction in any medium,
provided the original work is properly cited.
... Based on the idea of evaluating and transforming the unused parts of existing buildings located in the city center, "functionalizing and transforming the roofs," is a new approach in sustainable urban transformation (Nawaz et al., 2015). As the roof surface can be converted into a useful area, the building becomes economically and functionally more efficient and has a better impact on the city (Morau et al., 2017;Lee et al., 2015). ...
... This is because some of them have been informed about the green roof by reading books and articles. As Morau et al. (2017) pointed in their study, meantime the roof surface converted into a useful area, Zorlu Center became economically and functionally more efficient and had a better impact on the city. ...
Full-text available
As a solution to the rapid urbanization problem, green roof applications in urban centers have gained popularity. This study aims to investigate the green roof awareness of the casual users of Zorlu Center located in Besiktas, Istanbul. The social perception of the green roof, which is defined as an urban balcony,-by its architect, located in an intensively used area, has been handled as a case study. Perception enables people to critique, interpret, distinguish, and analyze their environment according to their core values to adapt to the environment. In this study, the perception has been associated with socio-demographic characteristics such as age, education, and attitudes. A field survey, designed to measure the impact of the green roof, was conducted with the 100 users of Zorlu Center. The most significant result of this study is that most of the participants are aware of the need to develop green roofs in Istanbul. This study shows that the commercial environment in the urban area, which has green elements such as the green roof, helps to renew and revitalize the city. It has been found that the green roof application of Zorlu Center attracted the users from the settlements in its close vicinity. The people came to Zorlu Center, especially to this green area, for leisure time activities. The green roof application of Zorlu Center has positively affected the users in terms of physical and mental health. Also, it has been found that green roof applications have a contribution to sustainable urban development, especially in high-density city centers, considering the positive effects on the city silhouette and urban quality of life.
... The choice of materials with minimized environmental implications plays a dominant role in their sustainable profile. Sustainable and local material choices are needed in order to have more environmentally friendly GRs and VGS [103,115,[118][119][120][121][122][123][124]. ...
... Tables S2 and S3 (in Supplementary Material) present lists of GRs and VGS materials whose inputs have been previously calculated, with information on their unit quantities and life cycle phases. These values are taken from previously published LCA studies, dealing respectively with GRs [57,103,[119][120][121]125,126] and VGS [56,[115][116][117][118]122,127]. ...
Full-text available
Water in the city is typically exploited in a linear process, in which most of it is polluted, treated, and discharged; during this process, valuable nutrients are lost in the treatment process instead of being cycled back and used in urban agriculture or green space. The purpose of this paper is to advance a new paradigm to close water cycles in cities via the implementation of nature-based solutions units (NBS_u), with a particular focus on building greening elements, such as green roofs (GRs) and vertical greening systems (VGS). The hypothesis is that such “circular systems” can provide substantial ecosystem services and minimize environmental degradation. Our method is twofold: we first examine these systems from a life-cycle point of view, assessing not only the inputs of conventional and alternative materials, but the ongoing input of water that is required for irrigation. Secondly, the evapotranspiration performance of VGS in Copenhagen, Berlin, Lisbon, Rome, Istanbul, and Tel Aviv, cities with different climatic, architectural, and sociocultural contexts have been simulated using a verticalized ET0 approach, assessing rainwater runoff and greywater as irrigation resources. The water cycling performance of VGS in the mentioned cities would be sufficient at recycling 44% (Lisbon) to 100% (Berlin, Istanbul) of all accruing rainwater roof–runoff, if water shortages in dry months are bridged by greywater. Then, 27–53% of the greywater accruing in a building could be managed on its greened surface. In conclusion, we address the gaps in the current knowledge and policies identified in the different stages of analyses, such as the lack of comprehensive life cycle assessment studies that quantify the complete “water footprint” of building greening systems.
... Another LCA study on GRs by Table 5 Impact categories assessed in GRs studies. (Morau et al., 2017) recommended the use of lightweight and local materials to reduce adverse environmental impacts for longer transportations. Most of the LCA studies (Morau et al., 2017;Vacek et al., 2017) suggested to apply naturals materials for the green roof layer to reduce negative environmental impact as compared to man-made materials. ...
... (Morau et al., 2017) recommended the use of lightweight and local materials to reduce adverse environmental impacts for longer transportations. Most of the LCA studies (Morau et al., 2017;Vacek et al., 2017) suggested to apply naturals materials for the green roof layer to reduce negative environmental impact as compared to man-made materials. ...
Green roofs (GRs) have drawn huge global attention due to their multiple social as well as environmental benefits in the past decade. Recently, in-depth and comprehensive research on the environmental impact assessment of the green roofs is being conducted globally. In this study, the life cycle assessment of green roofs has been reviewed and analyzed. The environmental impact evaluation of GRs was assessed through five stages of life cycle assessment (LCA): material extraction, transportation, construction, operation/maintenance, and disposal phases. The content analysis method was adopted to classify the existing studies based on the research area and scope. The results of this study show that the green roof is a sustainable option over the conventional roof. Besides, GRs provides a number of benefits in the operational phase. However, there are several challenges needed to overcome including comprehensively evaluation of the disposal and transportation phase during LCA analysis. The use of recycled materials for GRs layers could be an optimal choice to reduce environmental impacts. Moreover, a comprehensive environmental and economic assessment needs to be carried out for future research work. In the end, a future research agenda is proposed to enhance the GRs design for its broader application in the building industry. Through this literature study, data can provide useful information for decision-makers to adopt green roof projects.
... Therefore, special attention must be paid to reduce greenhouse gas emissions during composting. Nevertheless, several studies (Li et al., 2010;Morau et al., 2017;Kuronuma et al., 2018) have shown that when compost is used on green roofs, this may lower CO 2 emission in the atmosphere. ...
... The uses of compost are growing as the means of improving its chemical and physical qualities are increased. The combination substrate/compost/earthworms on green roofs can help reduce the risk of flooding in urban areas by increasing rainwater retention (Graceson et al., 2013), and green roofs seem to be a sink for anthropogenic gas emission (Li et al., 2010;Morau et al., 2017). The addition of earthworms may allow improving the distribution of the substrate and compost within the substrate and may also improve soil structure, fertility and microbial activity (Paz-Ferreiro et al., 2015). ...
The aim of this study was to increase the ecosystem services provided by a green roof by ameliorating the biological and chemical properties of a commercial green roof substrate through the addition of earthworms and compost. We conducted a mesocosm (120 × 80 × 33 cm) experiment with a plant community comprising Hylotelephium maximum,Centaurea jacea, Lotus corniculatus, Koeleria glauca, and Dianthus carthusianorum. Two substrates were compared (i) a low complexity commercial green roof substrate with no alterations and (ii) a high complexity substrate with a layer of locally produced vermicompost and earthworms (Lumbricus terrestris) placed on top of the commercial substrate. The mesocosms were placed on the roof of a 20 m high building and at ground level. Results show that the percent of vegetative cover on both substrates was lower in the roof mesocoms than on those placed at ground level. This is explained by climatic conditions, such as higher light intensity at roof level. The substrate with earthworms and vermicompost had significantly higher enzyme activity, microbial biomass, and metabolic activity. This resulted in more available nitrogen and phosphorus for plants, increased the plant biomass, floral nectar volume and sugar concentration which resulted in the flowers receiving more diverse and abundant insect pollinators. This is the first time that adding earthworms and compost to a green roof substrate has been shown to have a significant effect on plant growth and plant-pollinator interactions. These findings will help in designing green roof systems that are more efficient at preserving ecosystem services in urban areas.
... e nutrition of vegetation is from the so-called growth substrate layer which could be mixed with compost and plays an important role in managing water. e protection layer could be composed of two plastic materials [25]: the first one prevents roots penetration into the support and could be made of highdensity polyethylene; the second one is a layer of drainage and filtration consisting generally of polystyrene. e support layer supports all the above mentioned different layers of the green roof and could be made of wood. ...
Full-text available
In a context of a climate change, bioengineering techniques and biomaterials are needed to reduce the human impact on the environment. Thus, in recent years, living materials have been used in environmental engineering applications. In the present paper, attention is restricted to the vegetation, and a brief review on its use as biomaterial in engineering control techniques is presented. The core of this review is a comprehensive overview of two important techniques using vegetation as living material for measures limiting the human impact both in extra-urban and in urban sites. In particular, the use of vegetation both as living material for soil erosion protection and river’s bank stabilization in extra-urban areas and as a part of green roofs or walls added to buildings in urban areas is presented. Considerations about the advantages and disadvantages of these techniques conclude this review.
In recent years, the interest in "green" solutions and in particular towards the use of green roofs and walls in an urban environment, not only for the reduction of the heat flow through the roofing due to the absorption of solar radiation and to its thermal inertia, but also for the mitigation of the heat island effect linked to the evapo-transpiration processes of plants. The benefits concerning comfort, and consequently the reduction of energy and economic costs, linked to the lower energy consumption for air conditioning under these green coverings, and the improvement of the quality of living in urban areas with a wider availability of green areas, which are often usable, are undeniable aspects of a "green" design and are widely investigated and documented. Only recently, however, research has started to address the issue of green design in terms of impacts in the life cycle, calculated according to the Life Cycle Assessment (LCA) methodology. In this research two equivalent coverings are compared in terms of summer thermal performance in the Mediterranean area: an extensive green roof and a ‘high-permeation' tiles roof covering, compiling the environmental performance of the life cycle with the phases of production, use and end of life, based on Environmental Product Declaration (EPD) compliant to the EN15804 standard.
Developed and crafted in Madagascar, the Raseta pump is a novel hydraulic ram (hydram) pump using a springs system. It operates differently from other pumps by the exclusive use of water energy due to the water hammer phenomenon induced by the sudden stop of the water flow. The present study initiates the investigation of the environmental impacts of this new type of hydram pump through a life cycle analysis using OpenLCA 1.8. It was found that, when operating in a small-scale water pumping system, the choice of the pump supply pipe material has small differences of environmental impacts, whether the material is made of steel or polyvinyl chloride (PVC). Moreover, compared to a solar pump for the same pumping flow rate, the use of the Raseta pump is more environmentally friendly and less harmful to human health. However, the actual advantageous utilization of such a system needs further studies such as social and techno-economic analysis.
Full-text available
Green roofs (GRs) and vertical greenery systems (VGSs) can contribute certain pollutants to stormwater runoff, affecting the quality of the receiving waters. The objective of this review paper is to discuss the potential impact of these systems on the quality of urban runoff. In the green building systems section, a series of materials used in greenery systems and their specific application are presented and environmentally relevant substances that could be leached out from these materials are identified as potential pollutants. After the identification of environmentally relevant pollutants that have already been measured in urban runoff and originate from these systems, an assessment of their pathways, fate, and impact in the aquatic environment is performed. Since GRs and VGSs are already considered to be solutions for stormwater quantity and quality management in urban areas, recommendations for mitigating their environmental impact through runoff are needed. It can be concluded that special focus should be placed on measures that target the pollution source, such as optimizing GR and VGS construction practices and materials used, as well as establishing appropriate decentralized stormwater treatment measures. Both of these approaches will help to reduce or even entirely avoid the emission of relevant pollutants into the aquatic environment.
Purpose Although the use of diverse types of bricks as the primary construction materials has been considered for many years, vernacular earthen materials are also widely used for construction with low potential environmental impacts in developing countries. In this study, the life cycle of two types of building materials for wall building is investigated. Design/methodology/approach For this purpose, life cycle carbon emissions (LCCO 2 ) are compared and embodied energy calculation for rammed earth and fired clay bricks as two construction materials. The complete construction chain using rammed earth, as a modern norm, and fired clay bricks, as the most common construction materials in buildings, is investigated in this research. Findings Studies on the constructions in Kashan city in the north of Isfahan province, Iran, as a case study, showed that replacing the fired bricks with rammed earth would reduce the CO 2 emissions up to 1,245 kg/ton and 4,646 MJ/ton (i.e. more than 95%) of the embodied energy. It also shows that the choice of building materials should be important for building practitioners to consider the environmental impact. Originality/value This paper provide life cycle assessment of building materials. The findings of this study help builders and owner to choose sustainable building materials.
Full-text available
Our objective was to investigate whether there might be excess cancer mortality in the vicinity of Spanish installations for the production of cement, lime, plaster, and magnesium oxide, according to different categories of industrial activity. An ecologic study was designed to examine municipal mortality due to 33 types of cancer (period 1997–2006) in Spain. Population exposure to pollution was estimated on the basis of distance from town to industrial facility. Using spatial Besag–York–Mollie regression models with integrated nested Laplace approximations for Bayesian inference, we assessed the relative risk of dying from cancer in a 5-km zone around installations, analyzed the effect of category of industrial activity according to the manufactured product, and conducted individual analyses within a 50-km radius of each installation. Excess all cancer mortality (relative risk, 95% credible interval) was detected in the vicinity of these installations as a whole (1.04, 1.01–1.07 in men; 1.03, 1.00–1.06 in women), and, principally, in the vicinity of cement installations (1.05, 1.01–1.09 in men). Special mention should be made of the results for tumors of colon–rectum in both sexes (1.07, 1.01–1.14 in men; 1.10, 1.03–1.16 in women), and pleura (1.71, 1.24–2.28), peritoneum (1.62, 1.15–2.20), gallbladder (1.21, 1.02–1.42), bladder (1.11, 1.03–1.20) and stomach (1.09, 1.00–1.18) in men in the vicinity of all such installations. Our results suggest an excess risk of dying from cancer, especially in colon–rectum, in towns near these industries.
Full-text available
Even if several studies and researches have demonstrated that green roofs significantly contribute to energy saving, indoor thermal comfort, urban heat island mitigation, rain-water management and air pollution reduction, environmental benefits of green roofs mainly depend on use of primary energy, natural resources or raw materials used in the construction.
Full-text available
Green roofs are an increasingly important component of water-sensitive urban design systems that can potentially improve the quality of urban runoff, reduce the energy consumption of buildings, and add esthetic value to the environment. The most important green roof abilities, which appear as a key feature in urban catchments are the ability of rainwater detention and retention and reduction in energy consumption. This paper aims to provide an overview of the effects of the application of the green roof strategy on the quality of runoff water and the reduction of energy consumption. The components of a green roof are discussed, and the advantages and disadvantages of different types of green roofs are assessed. In addition, the origins and concentrations of the main pollutants are discussed, moreover environmental cost-benefits of green roofs are also considered. In addition, the main factors that affect the quality of green roof runoff water, e.g., plant species, fertilization, pH, growth media as well as how green roofs could reduce energy consumption are discussed. Green roofs are considered as sustainable approach for runoff management with achieved aesthetical values and in combination with energy saving on heating/cooling. Hence, green roof causes a sufficient decrease in energy consumption and consequently in the related energy costs. It can help to improve the micro climate around the buildings and save money and also improve water quality. Therefore, green roofs may turn into a profitable investment. Some recommendations for future study also are proposed.
To examine the stormwater retention capacity and runoff water quality of a green roof in Chongqing, China, 19 rainfall event samples of runoff and dry and wet deposition were measured. The results showed that the green roof effectively retained stormwater runoff, with retention ranging from 35.5% to 100%, with an average retention of 77.2%. The annual runoff retention of the green roof showed that the retention volume and rate reached 758.7mm and 68.0%, respectively. When we compared the stromwater quality among the green roof, asphalt (control) roof, dry and wet deposition and rainfall samples, found that the green roof reduced the concentration of TSS, and could neutralize the pH of rainfall; however, it increased the concentrations of TN, NH4+-N, NO3--N, TOC, COD, BOD5, F-, Cl-, SO42-, K+, Ca2+, Si4+, DPb, DAl, DMn, and DFe. When we compared the pollutant loads from the green roof and rainfall samples, found that the green roof was a sink for NH4+-N, but was sources of NO3--N, K+, Si4+, Ca2+, TOC and DAl. Overall, the green roof was effective in reducing stormwater runoff, neutralizing acid deposition and abating the loading of most pollutants; however, the water quality of runoff was seriously affected by the soil substrate. Therefore, we suggest that green roofs need to be constructed of suitable materials in order to avoid deterioration of runoff water quality.
The present study evaluates the environmental profile of a PV-green roof (PV panels over a soil/plant layer) and other roofing systems (PV-bitumen, PV-gravel, gravel, extensive green and intensive green). The analysis is based on multiple life-cycle impact assessment methodologies (ReCiPe, etc), several scenarios (for example with and without recycling) and it provides a deeper analysis as well as additional results to authors' previous investigation about PV-green roofs. The evaluation of the PV-green system (in terms of material manufacturing phase) shows that PV laminates (multi-Si) and steel components (joist, decking, balance of system) are responsible for the greatest part of the total footprint, based on GWP (global warming potential) and ReCiPe. Among the roofs which do not produce electricity, material manufacturing phase reveals that intensive green configuration has considerably higher impact in comparison with gravel and extensive green systems. Concerning PV roofs, PV-green configuration on a long-term basis (by considering material manufacturing, use phase, transportation and disposal), after a critical point, pays back its additional environmental impact (related with the "green layer") and it becomes more eco-friendly than the other two PV roofs. Certainly, this is due to the benefits (cooling effect of evapotranspiration, etc) of the soil/plant layer which result in PV output increase. The above mentioned critical point is determined by means of ReCiPe payback time and greenhouse-gas payback time. Several environmental indicators are calculated and presented along with results from the literature. A critical discussion is also provided.
Sustainable water management is an important global action to alleviate the growing pressure on our water resources and a way to balance both socioeconomic and environmental water needs. Irrigation of green roofs and other urban green infrastructures often has a negative connotation in a water management context. This is especially the case in semi-arid regions where both water scarcity during summer and other water needs compromise the public support of urban irrigation systems. However, irrigating green roofs is also beneficial as it improves plant survival and temperature control. Information on green roof irrigation is still very scarce, and this review attempts to draw attention to alternative water sources and water conservation strategies in order to make green roof irrigation practices more sustainable. Suggestions for more sustainable green roof irrigation showed that water can be conserved by adapting irrigation requirements (i.e. by targeting the vegetation or materials), by using alternative irrigation sources (e.g. gray water and rainwater harvesting) or by controlling and monitoring irrigation regimes. Based on the deficit irrigation strategy, irrigation specifications for green roofs in different climates were proposed. It became clear that irrigation is essential during establishment and the first growing season on all types of green roof and in all climates here considered. Afterwards, irrigation is necessary on green roofs in (semi)-arid climates, and advised in small amounts in the other climates. If public awareness of sustainable water consumption is promoted and if green roofs are designed carefully, then irrigation practices can be sustainable in the long term and contribute to better urban life quality.