Urban and building integrated vegetation’

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University of Westminster, College of Design, Creative and Digital Industries School of Architecture and Cities MSc Architecture and Environmental Design 2018/19 Sem 2&3 Thesis Project Module

‘Urban and building integrated vegetation’ and the impacts on the environment inside the London urban area

Joao Silva September 2019 London, United Kingdom

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ACKNOWLEDGMENTS

Firstly I would like to express all my appreciation and admiration to my personal tutor and course leader Rosa Schiano-Phan, for her guidance, and for, not only guiding me through this program and final work but also in life challenges. For always motivating and encouraging me to give the best I could. Secondly, I would like to extend this feeling of gratitude, to the team of professors that have been all so thoughtful and ready to help in any difficulties over the process. Would also like to express my deepest gratitude to Hilson Moran for the valuable opportunity of cooperation in this project. An opportunity that gave me the confidence and experience to start to grow as a professional in this field. My special thanks to Amedeo Scophone for being my link with Hilson Moran and always being available to help me to solve the issues along the way. Besides that, I am grateful to my Mom for providing all the emotional and financial support I needed to conclude this or any other phase in my life. I also would like to thank the other students that were around during this process, always with words full of kindness and encouragement. Special thanks for the closest friends Carine, Julia and Nadya, for being present in all the moments I needed, you are a very important piece of this process. And last but not least, I would like to express my gratitude to the University of Westminster employees, which make possible for us students to spend so much time inside the building and to feel like being in a second home.

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ABSTRACT

Fig. 0 Environmental perspective of one of the studied scenarios.

The use of different typologies of vegetation has been acknowledged for years, since the beginning of cities' environmental conscious development discussions. And It is considered as an essential element in the role of conquering positive outcomes. Outcomes are related to human wellbeing inside a context of continuous urban expansion and densification. In various cities all over the globe, it is possible to spot an extensive use of different vegetation structures. This situation could not be different in London, a city considered to be the fourth city with a higher amount of vegetated area per inhabitant inside Europe. While this broad use of ‘green elements’ has been widely encouraged there hasn't been so much attention driven to the necessity of deeply investigating the possible final effects of its installation on the urban microclimate, related to thermal comfort and air quality. This work aims to evaluate the impacts of vegetation on thermal comfort and air quality in the

urban environment of London inside the context of the current push towards urban densification. The first step to reach the explained goals was to categorise and characterise the types of vegetation found in London, subsequently, define them as building and urban integrated vegetation. The second measure taken was to identify and start the environmental studies in areas that could portrait some of the air quality and thermal features of London's urban spaces. Studies that were conducted aiming to understand which scenario would generate more positive impacts. The findings suggest that the application of Urban and Building Integrated Vegetation (UBIV) can generate improvements on some typologies of open areas. The UBIVs can also improve indoor environments by amplifying thermal comfort. Additionally, the findings strongly propose that each typology creates a different impact on its immediate environment.

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TABLE OF CONTENTS

01. INTRODUCTION_________________11 02. LITERATURE REVIEW_____________14 02.1. Density_____________15 02.2 Air Quality___________16 02.3 Human Comfort______18 02.4. Vegetation__________20 03. CONTEXT______________________24 03.1.London_____________25 03.2. Studied sites________29 04. FIELDWORK____________________33 04.1. City of London______34 04.2. Red Lion Square____38 04.3. Outcomes_________42 05. ANALYTICAL WORK______________45 06.1.Introduction_______46 06.2. Outdoor work_____47 06.3. Indoor work_______59 06. OUTCOMES AND DESIGN APLICABILITY ____________________65 07. CONCLUSION___________________69 08. LIST OF FIGURES________________71 09. REFRENCES____________________75 10. APPENDICES____________________78

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01. INTRODUCTION

Fig. 01.1 Semaphore Project (Vincent Callebaut Architectures, 2019)

According to the World and Health Organization (WHO), there are over 4.2 million deaths per year from exposure to air pollution, with around 91% of the world living in areas where the air quality levels exceed the WHO limits. The high pollution levels strongly affect the low and middleincome countries; however, it also harms developed countries. Air quality being threatened is a well known and vastly discussed issue, encouraging conversations and actions all over the globe. Consequently, it is common to observe diverse projects proposals with the extensive use of vegetation, in addition to buildings that have already been built with the use of those elements. The discussion that this work wishes to start is of what is the real impacts of the use of vegetation towards human health and comfort. Having this purpose in mind, London is the studied scenario, considering that the city is an

example of the issues that can be spotted, in similar conditions, in other areas over the world. INDUSTRY COLLABORATION AND CONTEXT In the City of London, there are a high number of buildings dedicated to office spaces. Buildings with this typology are usually mechanically ventilated, due to noise and air quality issues. This fact led the Hilson Moran Company to collaborate in this thesis, with the aim of understanding if vegetation could improve the outdoor conditions to increase the number of natural ventilated indoor areas. RESEARCH QUESTIONS Understanding which are the impacts of the Urban and Building Integrated Vegetation, on the urban canyons in the city of London. Also comprehending how the different applications of

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greenery and different building geometries can influence those outcomes HYPOTHESIS •

The installation of the Urban and Building Integrated vegetation will create positive impacts on air quality and thermal comfort. The building and site geometry will influence the impacts caused by vegetation.

SIGNIFICANCE OF THE STUDY This research is significant due to its originality and the knowledge gap that exists, related to the real consequences of having different typologies and the amount of greenery inside dense urban areas. METHODOLOGY AND FINDINGS SUMMARY The conduction of this work started with defining the issues, answers, and hypotheses that would drove it. To a further understanding of the topic, the second step was naturally a literature review, with the use of published books and papers. The process focused on the research of population, density parameters and contents which were already produced before about the typologies of vegetation and their impacts. This section guided how to address density and also assisted in what outcomes to expect from the application of green elements during fieldwork and analytical work. The content of this portion of the work was also substantial to define and explain the concept of Urban and Building Integrated Vegetation (UBIV). The third section of this work is dedicated to the further understanding of the studied area, which in this case is London city, more specifically the Red Lion Square Gardens, which is an open vegetated space in Holborn. The outcome is acknowledging London’s brief story, climate, and issues related to population, density, air quality, and human comfort.

Following that, the work focuses on the fieldwork, which was conducted in the early stage of this research in two different sites in London. For the development of the fieldwork, the analysed sites were the City of London borough area and the Red Lion Square Gardens. Both sites were studied on two different dates and were divided into different spots, so wind velocities, air quality, dry bulb temperature, humidity and surface temperatures could be analysed. The used instruments were the Airflow pollution device, which can monitor non-stop, an anemometer, a surface temperature thermometer, and a co² measuring device. This section provides information on the characteristics of two different areas of London, in addition to findings related to vegetation typologies impacts on pollution levels. The following section is the Analytical work wich is the main exercise responsible for answering the research questions and confirming the hypothesis. This portion of the research is based on the conduction of investigations, for outdoor and indoor, starting with the base site, which is the Red Lion Square Gardens. From the base case onwards, more studies were developed, linked with the creation of more investigated scenarios in the same area. For the conduction of this section, the Envi_met software was used in the outdoor research, for wind velocity, temperatures, and pollutants analysis. The following step was the use of TAS Engineering for the indoor analysis related to temperature. The outcome of this section is the most substantial part of the work, consisting of the acknowledgement of strengths and weakness of introducing Urban and building Integrated Vegetation in the city and also which scenarios will make the best use of it. The last sections are dedicated to gathering all the main findings and for discussing which are the best practices related to the use of vegetation.

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02. LITERATURE REVIEW

Fig. 02.1 London wih applied greener, Living green city 2018

The literature review in this work aims to increase the perception of the discussed subjects, developing a good base on the understanding of the fieldwork and analytical work conducted. The first factor considered is the notion of density and its applicability, which is directly connected to the case scenarios built on the analytical task.

The second step is to display and discuss the concepts of thermal comfort and air quality, thoroughly mentioned in this work. The last section of the literature review is dedicated to discussing the concepts of Urban and Building-integrated vegetation and their possible impacts.

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02.1. DENSITY Density is one of the main characteristics of a city, shaping the project decisions, related to the size, height and the number of buildings in one area and also shaping the transportation patterns and other behavioural aspects of the population.

urban geometries (layouts) with the same density, which guided the analytical work.

DENSITY PARAMETERS “Density is used to describe, predict and control the use of land” ( Berghauser Pont & Haupt, 2007; DETR, 1998). “A city density has direct impacts on its air quality and thermal characteristics, influencing human comfort and health. It shapes how cities look, feel and are experienced in obvious and subtle ways, and it has important impacts on things like our quality of life and mental and physical wellbeing” (Rachel Cooper & Christopher T. Boyko, 2012). Density is extremely important in the understanding and planning of urban spaces, which can be measured in different ways. “Plot ratio is the ratio of the total gross floor area of a development to its site area. The gross floor area usually takes into account the entire area within the perimeter of the exterior walls of the building, which includes the thickness of internal and external walls, stairs, service ducts, lift shafts, all circulation spaces, and so on. The site area refers to the total lot area of the development, which, in most cases, is precisely defined in the planning document. Since the definitions of both floor and site areas are relatively clear in the measurement, the plot ratio is considered as one of the most unambiguous density measures. In planning practice, plot ratio is extensively adopted as a standard indicator for the regulation of land- use zoning and development control” (Vicky Cheng, 2019). “Site coverage represents the ratio of the building footprint area to its site area. Therefore, site coverage is a measure of the proportion of the site which s covered by the building.”(Vicky Cheng, 2019). Due to the characteristics explained before, considering the necessity of simple and reliable ways of measuring and comparing densities, the plot ratio, and site coverage was used for further analytical studies. For the development of this work was also essential to understand the variety of

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Fig. 02.1. Plot Ratio = 01 and site coverage = 25%, Vicky Cheng 2019

Fig. 02.3 Plot ratio = 0.5 and site coverage = 25%,, Vicky Cheng 2019

Fig. 02.4 Layout study 01, Vicky Cheng 2019

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02.2. AIR QUALITY

Fig. 02.5 Layout study 02, Vicky Cheng 2019

Fig. 02.6 Layout study 03, Vicky Cheng 2019

Humankind nowadays is facing various challenges and, according to the World Health Organization, the most significant threat against health is related to environmental pollution, prematurely killing 7,000,000 people every year. Pollution is shifting the planet thermal conditions and causing massive damage to natural resources, changes that are already starting to influence in human quality of life. In addition to that, trough high levels of air pollution, there have been numerous cases of pulmonary diseases and even deaths. According to researches developed by National Geographic, long-term exposure to air pollution can also generate short-term issues, as, eye irritation, headaches, and dizziness. For the United Nations public health agency the problem is prevalent in ‘low-to-middle-income’ countries, which doesn’t indicate that the most prominent cities around the world like, for example, London, are not facing those problems.

CAUSES The primary identified sources of pollution on the planet today are the burning of fossil fuels coming from all the different types of fuel-based vehicles that the majority of the globe’s population relies on to move around the cities. Other practices, for example, agriculture, through the use of pesticides, factories exhaust, mining, and indoor activities through the use of some equipment or even cleaning items, are also causes of pollution. According to the World Health Organization (2018), “Air pollution is closely linked to climate change the main driver of climate change is fossil fuel combustion which is also a major contributor to air pollution - and efforts to mitigate one can improve the other. This month, the UN Intergovernmental Panel on Climate Change warned that coal-fired electricity must end by 2050 if we are to limit global warming rises to 1.5C. If not, we may see a major climate crisis in just 20 years.” EFFECTS As mentioned before the effects of air pollution are inside a range, from minor issues to significant risks for human health and the world`s

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Fig. 02.7 Pollution sources, WHO Europe

ecosystem. The more severe effects on human health can be several respiratory hazards (asthma being prevalent on kids), among other body problems, including cancer or even enhancing the risk of miscarriage. Concerning the earth environment, global warming has been an acknowledged issue for most of the national governments, a phenomenon which is directly changing the world’s temperatures, consequently altering and even destroying the livable conditions of numerous habitats, causing the death of many species. Global warming can be directly connected to the depletion of the ozone layer, which is another pollution effect. The phenomenon consists of the ozone layer getting thinner, which makes possible the access to harmful UV rays. Another example of the consequences of pollution is acid rain. The acid rains, resultant of the burning of fossil fuels, can damage the crops and also water reservatories, being harmful to animals and humans through the food and water ingested. POLLUTANTS The pollutants can be divided and categorised into different groups. The first one to be considered should be the ‘primary pollutants’, which are a direct product of the sources, having as an example the Sulfur emitted by factories. The second group is composed of the secondary pollutants, which are resultant from the reactions between primary

pollutants. The most common air pollutants are particulate matters (PM2.5 and PM10), ozone (O³), nitrogen dioxide (NO²), carbon monoxide (CO) and sulfur dioxide (SO²). For this work, due to harmfull level against human health and the high concentration inside diverse cities with similar characteristics to London, the pollutants which will be further studied and analysed are the particulate matters and the nitrogen dioxide. The particulate matters are composed of numerous different materials, coming from diverse sources, which could be from natural sources, like fires, volcanos or dust storms, and also coming from men’s activities, like for example, burning fossil fuels, the use of motor vehicles, and any other type of residential or agriculture-related combustions. PM2.5 and PM10 are microscopic matter suspended in the Earth's atmosphere, which could be liquid or solid, and this name classification is based on the size of the particles. However, due to its microscopic size, both particle types can get inhaled, passing through the defensive nose hairs and reaching the lungs. The PM10, also know as coarse dust particles have diameters from 2.5 to 10µm (micrometres or microns), it can sometimes be thirty times smaller than a single hair diameter (fig 02.8). Fine particles or PM2.5 are even smaller, having 2.5 microns or less, for this reason, are only able to be seen with the assistance of an electron

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microscope. What makes these types of particles much more dangerous than the PM10 is the fact that, due to its size, PM2.5 particles can be carried from the lungs to the blood.

Fig. 02.8 PM sizes, US EPA 2018

Nitrogen dioxide (NO²) is an entirely human-made pollutant, basically coming from combustion processes, being a result of the created element plus the interaction with oxygen. Its primary sources are currently vehicles, mainly the ones fuelled with diesel, followed by combustion for power generation and heating. According to a report produced by PlantlifeUK, nitrogen dioxide is a pollutant responsible for a detrimental effect on biodiversity, by inhibiting plant growth. The report also states that 63% of the habitats and ecosystems across the country receive higher NO² deposition than what it could be tolerated. The global emissions today is six times higher than in 1850, and the projections are that the levels will continue high until 2050. In the UK, the last two decades brought a reducting of over 70% in the nitrogen dioxide concentration levels.

02.3. HUMAN COMFORT There are different ways in which human beings can experience a feeling of comfort. It could come from elements that are easier to be ‘measured’ like thermal comfort and sound comfort, to ones which are more subjective like visual and psychological comfort. There are numerous variables related to comfort achievement, changing from one person to the other and also being ‘different’ in each region of the planet. This shift in how people experience and feel in comfort in each part of the world is related to cultural, climatic and even socioeconomic characteristics of each place. Being aware of this phenomenon, all researches, and also analysis related to design achievements are developed based on a ‘comfort band’ that can change between environments. Nowadays, it is widespread to identify cities, usually with a high population and density, which, in several moments, are not achieving the considered comfort levels in indoor and outdoor environments, London included. THERMAL COMFORT “‘Thermal comfort’ is the term used to describe a satisfactory, stress-free thermal environment in buildings and, therefore, is a socially determined notion defined by norms and expectations. The idea of what is comfortable has undoubtedly changed from one time, place and season to another” (Chappells & Shove, 2005). Thermal comfort is directly related to the personal resistance of each

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Fig. 02.9 Heath island effect, Jolma Architects, 2018

human-being allied to the types and number of clothes used, also in addition to the activities currently being performed. Global warming, which, as discussed before, is directly related to the pollution levels increase, has been known for years as a phenomenon that is affecting the temperatures worldwide. In parts of the world, like Europe, where the temperatures did not usually achieve extreme levels in the summertime. It became much more common to have extreme temperatures during some days or even extremely hot days. Those heatwaves are presenting temperatures that can easily exceed the comfort limits set for this region, for example, in July, Paris registered the hottest day in history, with 42.6ºC average temperature, in the same month the UK recorded the second hottest day ever, with 38.1ºC average temperature. HEAT ISLAND EFFECT A widely discussed issue related to thermal comfort and cities is the Heat island effect, which is directly connected with the population growth and consequently, density levels mentioned before in this work. It is when areas with a higher constructed level, usually city centres, showcase higher temperatures than rural areas or even parts of the city with a less built area. The amount of site

coverage, combined with the used materials in addition to solar radiance can modify the resultant temperature of a city or from a small portion of it, as, streets, squares and also the indoor temperatures. Being possible to conclude that this effect is also functioning as one more way to decrease comfort in hot periods of the year. There is a probability that London will slowly become a more dense city, whit higher populated and built spaces, possibly increasing the heat island effect inside those areas. SOUND COMFORT

“Environmental noise, also known as noise pollution, is among the most frequent sources of complaint regarding environmental issues in Europe, especially in densely populated urban areas and residential areas near highways, railways and airports. In comparison to other pollutants, the control of environmental noise has been hampered by insufficient knowledge of its effects on humans and of exposure– response relationships, as well as a lack of defined criteria. Among the various effects of environmental noise, health effects are a growing concern of both the general public and policy-makers in the Member Status in 19


Europe” (WHO Europe, 2011). Noise pollution or noise annoyance is a difficult factor to measure; however, there are indications that several health issues are related to it.

02.4. VEGETATION There are many typologies of vegetation and groups of vegetation spread all over the globe, each one with a different impact on the environment it is inserted, consequently generating an effect on the entire planet. Over the years there have been numerous researches dedicated to the investigation of those results on a big scale, usually related to the vast green areas existent and how actions like deforestation, which has always been happening, are generating catastrophic effects towards the world's environment and its population. Forests have been widely known as mitigators of the climate changes and their impacts. An example of that is the Amazonian forest in Brazil, which, according to an article by David Werth published in 2002, it was already possible to spot local and global climate changes related to its deforestation. It was also indicated by their studies and analysis that this practice would only generate more climate changes. It is possible to find, on a much smaller scale, vegetation inserted in highly built environments, which is entirely justified by understanding the common knowledge that those elements can enhance comfort. MENTAL HEALTH The existence of a certain amount of vegetation in urban space will probably increase the sensation of comfort, being essential to understand that it is an abstract element, for the reason that it is deeply connected with mental health factors. “Attention-restoration theory proposes that the natural world promotes recovery from mental fatigue that occurs during the performance of cognitive tasks that require the prolonged maintenance of directed attention (Kaplan 1995), whereas stress-reduction theory argues that natural environments facilitate reductions in physiological arousal following stress” (Ulrich et al. 1991). Increasingly, evidence suggests that the availability and quality of neighbourhood green spaces are associated with greater well-being

(White et al. 2013) and lower levels of depression, anxiety, and stress (Beyer et al. 2014). These benefits may be gained from intentionally interacting with nature (e.g., through visiting neighborhood green spaces or spending time in a garden), from incidental interactions whereby people are exposed to nature as they engage in other activities (e.g., walking to the shops), or indirectly while not actually being present in nature (e.g., viewing it through a window)” (Keniger et al. 2013). Those findings can bring the understanding that small vegetated areas or even small green elements (flowers and other plants) in everyday sight can improve human’s quality of life and probably decrease health issues. POLLUTION “The vegetation in the urban environment influence the pollution levels based on two processes - deposition and dispersion. Deposition describes the process of the airborne particles of pollution being attached to the surfaces while passing close-by. As plants usually have large surfaces area per its volume, thus the possibility of deposition is increased 10-13 times in comparison to smooth manufactured surfaces like glass or concrete. The second process of dispersion, in simple, refers to the porosity of the vegetation, therefore to the effect of the surface texture on the wind field” (Janhall. 2015). Another process that can occur is the purification of the air, widely observed in the CO² cycle. The deposition and dispersion processes are linked, for example, with the LAD of trees. LAD is the Leaf area density of a tree, and each tree typology has a different one. This characteristic changes its geometry, consequently changing its capacity of deposition and dispersion. Considering that, it is extremely important to take into consideration the trees typologies when analysing pollution levels in a vegetated area. VEGETATION TYPOLOGIES For the further researches and analysis developed in this work, it was indispensable to understand what types of vegetation are possible to be found in built-up contexts, with similar characteristics to London city. It is possible to spot

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that all these types of greenery which are inserted in areas with high density have the attributes of being connected with the urban tissue of the city or with the buildings, which could happen in different ways. Large urban parks, like the Central Park em New York, the Regents Park in London or The Ibirapuera Park in São Paulo are examples of green areas that are connected with the city. Every day in each of those parks, diverse activities are happening, and people often use them as walking or cycling paths towards their destinies. The parks are part of the population's routine, changing their experience of the city itself and, as discussed before, probably the air quality, thermal and sound conditions. The big parks can function in many ways as integrated areas concerning the built area surrounding it. A similar effect can be obtained and observed in smaller green areas. This typologies of vegetation can be denominated as ‘Urban and building Integrated vegetation’. Due to the common characteristic of being directly integrated into the building structure, that is, applied on the building wall or roof surface, or the urban tissue, being part of the city environment and routine.

Fig. 02.10 Living wall - Edgware tube station, Biotecture, 2011

Fig. 02.11 Vertical Forest - Skyscraper complex, Buro Ole Schereen 2017

LIVING ROOF “Green roofs are roofs that are purposely fitted or cultivated with vegetation. They are also be known as living roofs, eco-roofs or vegetated roofs” (CIBSE 2007). According to Kibert (2008), there are two types of green roofs: Extensive and Intensive. The extensive are the ones that don’t require intensive maintenance, with little or no irrigation or fertilisation, and also don’t need a significant slope (up to 40%).

Fig. 02.12 Living roof - New providence wharf , Zinco 2012

On the other hand, the Intensive living roof typology requires intensive maintenance, being actual gardens. This type of living roofs can be formed by bushes, ponds and even trees being much more complex systems with much more massive structure. Some authors also describe a third type of green roof as 'simple intensive' which usually comprises herbaceous plants, grass and shrubs.

Fig. 02.13 Square Garden - Woburn square

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“Simple intensive green roofs can be constructed using varying depths of the substrate, thus combining elements of extensive and intensive roofs” (Newton, Gedge, et al. 2007). VERTICAL FOREST Vertical forests are a relatively new strategy designed to amplify the amount of vegetation in dense areas. Usually skyscrapers with numerous green elements distributed on several floors along with the building height. Is possible to affirm that a vertical forest is a gathering of multiple intensive living roofs on the extremities of the facades. It is a typology that aims to develop metropolitan reforestation, amplifying the biodiversity, thermal, sound and mental comfort in the core of the cities. One of the most famous projects of Vertical forest in the world is the ‘Bosco Verticale’, in Millan city centre, hosting 800 trees in addition to a wide range of scrubs and other plants. Based on this example, it is a possible indication that the creation of numerous vertical forests in one city can generate a healthier environment while increasing the city density. However, it is essential to state that those scenarios should be built or at least simulated for having the correct understanding of the vertical forests, considering all the variables (including the resistance of trees to this situations) related to vegetation and high rise buildings.

most common examples are facades with climbers plants planted on the base of the building, garden ‘pots’ distributed over the facades, modular system with grid pannels and also the ‘Patrick Blanc’s technology. ‘Patrick Blanc’s technology’ is described by himself (with the patent title) as ‘Design for growing plants without soil, a vertical surface’ based on his studies of the tropical rainforests. According to Blanc (2008), it is a system built on PVC, using felt instead of soil, which is a material that has the capacity of retaining water and also of developing an environment in which the roots can grow. There are numerous companies in the UK using living walls systems based on the technology described by Patrick Blanc, which can also be called of hydroponic plantation method (planting without soil, using water).

LIVING WALLS For a few years now, ‘green walls’ or ‘living walls’ have become a widely used design method, claimed to be a strategy to increase the natural environment inside highly densified areas. Coming with all the possible positive outcomes related to improving comfort and air quality. There is an immense variety of plants that can be used on a living wall, from the most common grass to a diversity of bushes and climbing plants. There are also diverse types of ‘systems’ to build a green wall structure, with different irrigation methods and different ways to attach the green elements to the surfaces, what is directly related to the type of vegetation used and also the amount and the area of the building which the structure is planned to be installed. Nowadays, there are several technological solutions to establish green walls. The

Fig. 02.14 Bosco Verticale, Bios 2018

LIVING WALLS AND THERMAL COMFORT There are several studies published, exploring the relation between living walls and thermal comfort indoor, which is a relation that is going to be further studied in the analytical section of this work.

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“By intervening in the heat transfer with green walls, all the three temperatures are consistently lower than the bare wall, which indicates the reduced heat transfer and resulting cooling effect produced by the green wall. However indoor temperatures attained through this single intervention of 45–47 ◦C are still far from the comfort temperature of 26–28 ◦C which shows that although the green wall reduced the cooling load by a certain amount, there remains a need for mechanical cooling alongside it. The benefit, however, comes from the reduced energy consumption and reduced peak on the HVAC system which consequently reduces the size of the mechanical cooling system resulting in lower capital and operating costs of the cooling system” (Mahmoud Haggag∗, Ahmed Hassan, Sarah Elmasry, 2014). The study above was developed in the United Arab Emirates, displaying distinct temperatures and comfort level concerning the UK, however, serves to showcase the positive impact that this green element can generate.

an avenue. They typically have trees, which could have big canopies and also be tall, sometimes reaching over 25m. According to those characteristics, it is possible to say that this type of vegetated area can be called ‘Green Pockets’.

Fig. 02.15 Woburn square, Bloomsburry square and gardens, 2018

GREEN POCKETS The therm ‘Pocket’, when related to urban design, is usually linked to small and open areas inside a built environment, which could be highly densified or not. These areas can be a result of a planned urban tissue or from informal settlements. In dense environments these spaces are usually left in the middle of squares, permitting solar access, natural ventilation and sky view factor enhancing for indoor spaces. Having in mind, the characteristics explained before the square gardens in London can be considered as pocket spaces. However, the square gardens are areas, usually, intensely vegetated, modifying the thermal comfort and air quality characteristics of the city. The square gardens are common in London, existing various on the city centre with similar characteristics, a sample of this could be the Bedford square and the Woburn square. The features of the Square Gardens are usually of having the size of one or two blocks, with buildings surrounding it, many times could be connected to

Fig. 02.16 Bedford square, Bloomsburry square and gardens, 2018

Fig. 02.17 Red Lion Square gardens, Bloomsburry square and gardens, 2018

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03. CONTEXT

Fig. 03.1 London tourist map, tripindicator, 2018

Context studies are essential to the understanding of the outcomes of the analysis, considering that the environment where the researched object is inserted influences not only the results but also defines the best way to address the issues. It also brings an understanding of which

are the best strategies to investigated the researched topics. In this work, the study of the London context was essential to guide the site choosing. Where also important to comprehend the further findings in the fieldwork and analytical work sections

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03.1. London CLIMATE London is a city which is not directly connected to the ocean but is located in the United Kingdom, which is an Island, being around only one hour's distance from the sea. It is understandable that the climate is influenced by this proximity with the ocean, in addition to the warm Gulf streamflow. These characteristics justify the environment in London being slightly cold, with high humidity and with constant rainfall during the year, which can be characterised as a mild oceanic climate. London location on the globe, is in Western Europe, with latitude: 51N, on the 51st parallel North and longitude 0.11 South. The weather is less intense than in the rest of the country; this probably happens because the city is located in the south, inside an area called London Basin. The London Basin is considered to be a sheltered area, presenting a slightly warmer climate and also slightly less rainfall, the city is located between the Chiltern Hills, on the north from London, and the North Downs, which is on the south. London has also been presenting climatic variations in different metropolitan areas which can be a clear indication of a heat island effect, caused by the highly built spaces, which creates different conditions towards the centre of the city. TEMPERATURES London presents a daytime annual average air temperature of 11°C, with an 18°C month average temperature in July and 5.5°C, having a warmer period from April to October. According to weather spark collected data (2019), “the warm season lasts for 2.8 months, from June 15 to September 7, with an average daily high temperature above 20°C. The hottest day of the year is August 1, with an average high of 23°C and a low of 16°C. The cool season lasts for 4.0 months, from November 16 to March 18, with an average daily high temperature below 11°C. The coldest day of the year is February 7, with an average low of 4°C and a high of 9°C”. PRECIPITATION According to the Met Office Climate data, in 30 years there was an average of 106 days of

rainfall per year, going against the common knowledge that London is a rainy city. In other words, only 29% of the days in one year had rainfall, having an average rainfall of 557.4mm per year. Numerous cities over the globe have higher rainfall levels considering annual average, for example, Miami, Rio de Janeiro, and Mexico City had reached an annual average of more than 1,000mm of rain. FUTURE During the research, a necessary process is to understand the future characteristics of the studied sites. For this reason, the climate data was extracted representing the present days (2018) and also representing the future (2050). To be able to compare and analyse current and future climate conditions related to dry bulb temperature, it was defined as a comfort benchmark, considering comfort to be between 10°C and 25°C. The findings of dry-bulb temperature were considered the comfort benchmark. The future presented fewer hours inside the comfort band, which was proved by analysing the psychometric charts for each case. This situation can probably be explained by understanding that with climate changes, increasing temperatures all over the globe, the same will happen in London, having more hours with higher temperatures than 25°C. The comparative analysis also displayed higher levels of cumulative rainfall in ten months of the studied year in the future (2050). According to the studies, the amount of solar radiation, in all different orientations will also be higher in the future scenario. DENSITY AND POPULATION London is the largest city of the United Kingdom, sheltering a massive number of people from all around the globe, who continue to come every year, mainly searching for job opportunities. It is a fact that London is a city in constant development and population growth. Due to the higher number of opportunities and higher immigration levels from 1980, the city suffers an enormous growth in its population. In those twenty years, there was an increase of over 1,000,000 inhabitants in the town. According to the latest recorded data from the office of National Statistics, which was developed in 2016, the city of London,

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known as Greater London, had a population of 8,787,892 people. The London datastore provided a current projection which puts the population at over 9,200,000 by 2021. Analysing the London datastore provided data is possible to spot that in the years from 2001 to 2011, the higher increase in the population (20%) occurred in the centre of the city. The population growth, mainly in the centre portions of the city, indicates a necessity of enhancing the amount of available housing. Concerning the population's age, London is considered to be a “young city”, especially when compared with the rest of the United Kingdom. However, there is a growth prevision related to the number of people with 65 years old or more inhabiting the city in the next years. This fact and the population growth as a whole would probably develop many issues related to access to services, like health care and social care.

the city which are already built, or in portions with unbuilt lands. Even though the projections for London displays an increase in the population density in the next years, the publications indicate that London could have more built areas, with increased density. This statement was developed based on comparisons with other cities in Europe. One of the areas of London with a higher density is Islington, having around 138 inhabitants per hectare, in Madrid city centre there is an average of 286 inhabitants per hectare, displaying more than double of the density in the city of London.

DENSITY AND HOUSING CRISIS “London’s population is growing rapidly and could reach over 11 million people in 2050. As a result, the Mayor’s housebuilding targets have been increased to a minimum of 42,000 homes a year. While this increase is welcome, the Greater London Authority’s calculations suggest that London needs between 49,000 and 62,000 new homes every year. In practice, Savills estimates that an average of only 32,000 homes a year will be built over the next five years" (Rachel Cooper & Christopher T. Boyko, 2012). The current London city government claims to be aware of the possible housing crisis that London is and will be facing in the next years. According to studies and publications made to address London city issues, the ‘London first’ team has been already discussing possibilities to solve the housing issue. The primary considered outcomes are related to generating spaces with a higher built area that could become housing and services units. This change could happen in areas of

Fig. 03.2 London wind rose

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Fig. 03.3 Psychometric chart – London present (2018)

Fig. 03.4 Psychometric chart – London future (2050)

Fig. 03.5 London Temperature graph (K) 2050

Fig. 03.6 London Temperature graph (K) 2019

Fig. 03.7 London cumulative rainfall graph

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POLLUTION According to the most recent data of the London Atmospheric Emission Inventory, more than 2 million people are living in unhealthy situations related to air quality. Also, it is possible to spot that there have been breaches related to the legal levels of pollution. “In 2017, London saw its first breach of annual pollution limits just five days into the new year, and in 2018 it occurred within a month. However, three months into 2019, no such breaches have taken place” (The Guardian, March 2019). Exclusively in terms of nitrogen dioxide (NO²), until 2018 London was displaying levels close to the ones found in New Delhi and Beijing, and much worst in comparison with cities like New York and Madrid. On the other hand, recent studies conducted by the London Atmospheric Emission Inventory also indicates that the NO² emissions suffered a 9% reduction. However, there is no statement related to particulate matters (PM2.5 and PM10). There have been registered in the UK more than 40,000 deaths related to lung and heart diseases caused by air pollution. According to the city hall, and the mayor’s statements, the administration is keen about reducing pollution levels in the city. For this reason, there have been several changes conducted by the team, being a part of a series of measures to get the most polluted areas back to the legal pollution levels. One example of those measures is moving the buses which have lower pollutant emissions to more contaminated areas of the city — in addition to that, toughening the law, introducing fines related to high polluting vehicles in certain regions.

Fig. 03.8 Smog in London, Kathy deWitt/Alamy, 2019

Fig. 03.9 NO2 levels in London, LAEI, 2016

VEGETATION Researches indicate that London is a much more ‘green’ city that is believed by its public in general. According to these studies, London has today more than eight million trees, having from its overall area, 47% of green space and 60% classified as open spaces. With the numbers displayed before, it is comprehensive that London is considered to be the fourth greenest city in Europe. The city also shows numerous living walls and 700 catalogued extensive and intensive green roofs.

Fig. 03.10 Map of London only diplsying rivers and vegetation, GIGL, 2014

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03.2. Studied sites

Road, an area which is between the High Holborn Road and Theobalds Road.

Due to the necessity of further understanding the different urban settlements in London, with different densities, and their possible impacts on the immediate environment, for the development of this work, two sites were selected and studied inside London.

03.2.1.

City of London

GENERAL CHARACTERISTICS It is the oldest local authority district inside London, containing the historical centre and the first business area of London. The borough is located in the north of the River Thames, which is where London started to be developed by the Romans in first century AD. Considering its development is understandable that nowadays this area is extremely dense with the highest number of tall buildings inside London.

03.2.2.

Fig. 03.11 Map of London boroughs, Hidden London, 2012

Red Lion Square Gardens

LOCATION The Red Lion Square Gardens is known as being one of the ‘Bloomsbury Gardens’. Bloomsbury is one area of London that doesn't have official boundaries, but it is understood as an area inside the centre of London. Bloomsbury is a district that is famous for gathering a considerable number of museums, universities, coffee shops, and square gardens.

Fig. 03.12 Birdview of the City of London borough, mail online, 2018

Officially the Red Lion Square is located in Holborn, which is inside the Camden Borough and started to be developed in the 14th century. Holborn has a population of 3,289 people and an area of 51.786 hectares. 14.3% of the land is occupied with public green spaces, and there is a high number of residential buildings along with numerous other services. The exact location of the Red Lion Square is in the WC1R 4QG postcode, being accessed by the Drake Road (main street) and Red Lion Square

Fig. 03.13 Red Lion Square gardens

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HISTORY Red Lion Square Gardens is originated from a land portion denominated Red Lion Fields, and the name comes from the Red Lyon Inn and red lion street. The Red Lyon Inn was established in the 16th century and considered one of the most prominent hotels in London’s history. Around 1680 the Red Lion Fields area suffered a new urban design, reducing the field area, being occupied with residences and leaving in the square in the middle. The square is known today as Red Lion Square Garden, keeping the same size but passing through several renovations over the years, being the first one in 1730. During World War Two, the area was severely damaged by bombing, for this reason, only a few houses are still original, most of them having had changes on the facade around the 19th century. In 1895 the square started to be managed by the London city council. CHARACTERISTICS The immediate area where the square is located is predominantly residential but also having a portion of around 45.3% of the land occupied by other services, like shops or universities, for example, is possible to spot buildings entirely residential, entirely commercial or with mix use. The heights of the surrounding buildings can be from around 9m to over 35m. The square is open to all and managed today, more specifically, by the London Borough of Camden. The garden has a community group called ‘friends of the Red Lion Square Garden’ which are responsible to preserve its history and do all the maintenance of the space. GREENERY The square displays circulation areas in concrete and more significant areas covered with grass. There are six types of trees planted in the square, as cherry trees and elm trees, but the majority of trees are the plane tree, from the species ‘Platanus x Hispanica’, being around 15 trees of this species in the square. This species of trees usually presents a height of 15 to 20m and a canopy size of 8m in diameter when wholly grown (usually over 24 years old). The species is known to be able to tolerate pollution and intense weather,

being widely used over Europe, mainly in dense environments. POLLUTION According to research conducted ten months ago there area classrooms in Holborn area with pollution levels almost 27 times higher than the permitted by the World Health Organization standards. According to the data collected on the closest monitoring station (Camden, Holborn, Bee midtown), this area usually presents high levels of Particulate matter and NO². It has reached levels above 100ug/m³ several times a week during the last analysed year (2018 to 2019)

03.2.3.

Density studies

For a deeper understanding of the different levels of density between the studied sites, quantitative research was developed. In both regions of the city one area of around 44,800m² was selected considering the locations where the studies were conducted. The study worked as a representative parcel of the entire space. In this selected portion of the boroughs (Holborn and City of London), it was calculated the percentages of the built site coverage and the greenery site coverage, in addition to the plot ratio calculation. To the calculation of green spaces, it was considered all greeneries, including any vegetation, from parks to single trees The count results have shown that the vegetated area was equal to 3% of the city of London’s analysed total area. On the other hand, the Red Lion Square examined region, presented 12% of the vegetated areas, which is understandable considering the existence of the Red Lion Square, against one area which doesn't have any open green spaces. It was interesting to realise that between the case studies it was presented only a 10% difference in the built site coverage, Red Lion area with 42% against 52% of the City area. Those findings can indicate that even though the sites started to be developed on different epochs and the City of London suffer much more changes in its urban structure during the years, which much higher levels of people using the area every day, the land area distribution is not so different between them. The most significant

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difference between cases is the plot ratio, The Red Lion Square scenario presented a plot ratio of 3, while the City scenario has 10, over three times built area than the first one, with similar site coverage. Inside the studied City area there are buildings with heights from 6m to 180m (30 St Mary Axe or ‘The Gherkin’), compared with the Red Lion

which has from 12 to 36m buildings. It means that considering the floor to ceiling height of each level as having the same height (for comparison sake) the City has a total average of 20 floors against 8 of the Red Lion. Those foundings, showcase the ‘power’ inside verticalization of cities when related to the density factor.

Fig. 03.14 Density study – City of London

Fig. 03.15 Density study – Red Lion Square Gardens area

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04. FIELDWORK

Fig. 04.1 Red lion square diagram of pollution levels

The conduction of fieldwork was essential to build a notion of the environmental characteristics of the studied areas concerning its surroundings. It was important to analyse and study between sites with different developed geometries and density characteristics, as explained in the last section. This comparison would probably permit a deeper investigation between very different environments, one which is a symbol of London`s business power and another site which showcases

a neighbourhood organisation common to be found, with a very similar structure, in other London areas. The Red Lion Square settlement is a representation of this replicated design all through the centre of London, an area in which the neighbourhoods were designed in similar periods, displaying this ‘courtyard typology’ with green pockets in the middle and short rise buildings surrounding it.

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04.1. City of London 04.1.1.

Introduction

As displayed before there is a lack of vegetated spaces and a considerable number of buildings under construction in this area, in addition to a high number of materials in concrete and asphalt. There are also numerous buildings with the facades covered in glass, and it is essential to reaffirm that it is an area which serves as a home for most of the tallest buildings of London. It is also possible to identify diverse vegetation typologies. Some of the examples of vegetation are, trees placed along a road, trees placed on a small cemented square, small gardens, and also living walls. HYPOTHESIS Considering the characteristics of this site concerning the knowledge extracted from the literature review, the hypothesis were: •

The air temperature in the entire analysed area can be higher than in the rest of the city, due to the urban heat island effect, taking the building heights and materials under consideration The building's shadow can protect the ground surfaces, reducing the surface temperatures, leading to a lower resultant temperature as a consequence. The wind tunnels formed by the building's obstruction can also reduce surface temperatures and finally resultant temperatures. The impact of buildings towards wind velocity will, at least, modify the concentration of pollutants. Pollution levels will probably be higher in this area, due to the existence of buildings under construction, and the high number of cars.

METHODOLOGY The methodology for this part of the fieldwork was of conducting a ‘walk’ of one hour along the area, making sure of passing by spots that presented the different uses of vegetation, and also the completely non-vegetated areas. The ‘walk’ was divided into 12 different spots where the

measurements were taken on two different dates at the same hour. The measures happened at 2 pm, first in 16/05/2019, which was a sunny day, with 37% average relative humidity, prevailing east winds with 14.2mph velocity and an average temperature of 16°C. The second measured day (17/05/2019), had an overcast sky, with 78% average relative humidity, northeast prevailing winds with 9.9mph speed and an average temperature of 12°C. For the conduction of all the fieldwork the factors taking into account were; temperature, humidity, sound levels, pollution levels (NO², PM2.5, PM10, and CO²), wind speed, and surface temperatures. The equipment used to investigate the environment was the Airflow pollution device, which can monitor non-stop, an anemometer, a surface temperature thermometer, and a CO² measuring device. These measurements were taken in each spot. LIMITATIONS There are several variables which can impact on the results, from the site geometry, related to the position and size of the buildings, materials and also the volume of the open spaces, to environmental characteristics of the studied period in time, for example, wind velocity, solar exposure, number of users and amount of vegetation. All these variables generate a problematic situation when related to built comparisons between the different analysed spots. This also makes it more complicated to establish a ‘cause x effect’ relation between the existence of greenery and the various outcomes, as it is hard to define which of the variables are causing the results.

04.1.2.

Outcomes

Sound levels were quite similar in both analysed days, the higher difference between days showcased was in the spot 12. The spot 12 is an area located on the side of the 20 Fenchurch Street building (‘The Walkie-talkie’), which has a 700m² green wall installed.

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Fig. 04.2 Map of the measured spots in the City of London borough, google maps, 2019

Fig. 04.3 Spot 03, 2019

Fig. 04.4 Spot 04, 2019

Fig. 04.5 Spot 09, 2019

Fig. 04.6 Spot 05, 2019

Fig. 04.7 Spot 07, 2019

Fig. 04.8 Spot 12, 2019

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Regarding sound levels, the major difference of 36 dB (fig. 04.4) probably happened because of the number of people who were occupying the spot at the measured moment. The high levels can also likely be linked with the high wind velocity (6.9m/s) spotted on the same day with higher sound levels (100 dB). In both of the analysed days, the air temperatures in the spots were higher than the air temperature average measured by the weather station for that time (16°C and 12°C). The wind which is continually causing air exchange can be the reason for these temperature differences. However, it is essential to state that this is an indication of the possibility of changes in the resultant temperatures. The main outcomes related to pollution levels were that, according to the isolated spot measurements, the NO² levels, in both days, were lower than 200 ug/m³, which is considered to be not harmful. Was also spotted that on a sunny day the concentration in all spots was higher than in the overcast day, considering that the sunlight makes

possible for the ‘life cycle’ of the NO² to continue, it can be related with the fact that in the 17th, levels were not so high due to the transformation of NO² to NO. When investigating the particulate matters (PM2.5 and PM10) the first finding was that, in the overcast day, the spot 12 (with the big living wall) presented very high pollutant concentration, over 80ug/m³ of PM2.5 and over 100ug/m³ of PM10, which are considered to be unhealthy. This result can be expected considering the trap effect that vegetation can cause, related to pollution particles. The levels of pollutants can also be linked to the geometry of the space, which could be generating, in the studied day, a ‘shelter effect’, reducing wind velocities, consequently reducing the `wipeout` of the pollutants. Checking the data for this spot was possible to see that, at the moment of the measurements, the wind speed was around 0.1 m/s, proving that the wind velocity was slow.

Fig. 04.9 PM 2.5 levels chart

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Fig. 04.10 PM 10 levels chart

Fig. 04.11 NO2 levels chart

Fig. 04.12 sound levels chart

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04.2. Red Lion Square 04.2.1.

Introduction

This site presents an entirely different structure in comparison with the City of London borough, considering that it has such a smaller scale, and the spot measurements are much more concentrated, meaning that, it is the `same environment` in all measured areas. HYPOTHESIS Considering the characteristics of this site concerning the knowledge extracted from the literature review, the hypothesis was: •

Due to the amount of vegetation, considering the evapotranspiration cooling effect, the area will probably be cooler than the average air temperature presented in the city. Considering the ‘canopy effect’ of the trees is possible that the pollutant concentration will be higher in some areas of the square. Due to the trees' geometries, the wind speed will be lower inside the square, being one more indicative of higher pollution levels in the area. The shading provided by the trees will reduce solar exposure and direct radiation, cooling the surface temperatures and consequently making the resultant temperatures cooler. Most of the areas covered in grass should also create the same process of lowering the resultant temperatures.

METHODOLOGY For this site, the methodology consisted of dividing the area inside the Red Lion Square into 12 different spots, in addition to a separate spot

outside the square, located on the main street (Drake street). This decision was made to assure that the entire area of the square was being measured, aiming a further understanding of the site as a whole. The strategy was to spend the least time possible, realising the measurements to avoid any abrupt weather shifts during the process. There were also analysed in two different days but at 11 am. The first day was 23/05/2019, with a sunny sky, average humidity of 56%, presenting southwest prevailing winds with 3.72 mph speed and an average dry bulb temperature of 20°C. The second fieldwork in the site was conducted almost two weeks later (07/06/2019), in an overcast day with light rain, showcasing 80% of average humidity, prevailing east winds with 13 mph speed and air temperature of 15°C. The same environment characteristics (sunny day an overcast day) and equipment analysed and utilised in the City of London site were repeated for these measurements. LIMITATIONS The most significant limitation of the fieldwork in this site was to define if the vegetation is causing any impact, considering the different typologies and the height level where the measurements were taken (around 1.20m of the ground). If in the first scenario the complete change of the environment’s geometry and conditions was an issue, in this situation, with the spots so close one to the other it is also complicated to define what of the environmental variables discussed before are generating differences in the outcomes between measured areas.

04.2.2.

Outcomes

The sound levels are consistent in both days, all the spots, including the one at the main road, were in a range of 10 dB difference, from 70

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Fig. 04.13 Map of measured spots Red Lion Square gardens

Fig. 04.14 Spot 01, 2019

Fig. 04.15 Spot 02, 2019

Fig. 04.16 Spot 03, 2019

Fig. 04.17 Spot 11, 2019

Fig. 04.18 Spot 12, 2019

Fig. 04.19 Spot 13, 2019

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dB to 81 dB in the first day, and from 80 dB to 90 dB in the second day (fig 04.15). The spot 13, in the Drake street, presented the higher noise level in both days, but the areas close to the road (the extremity of the park) all showcased higher levels, sometimes with only 1 dB difference from the spot 13. For this reason, it was not possible to identify a pattern related to the existence of vegetation. Wind velocities on the site were very low corresponding to the indicated wind velocities of the analysed dates. Air temperatures were slightly higher than the average calculated by the weather station, which is quite understandable, considering that was a slight change of the temperature (around 1.5°C in both days), and the measurements were done in a local scale. The further investigation of the pollutants led to far more concrete findings, by showcasing much higher differences between spots. The first interesting outcome was that the higher concentration of particulate matters (PM2.5 and PM10) was not found on the street but inside the square area. Considering what was already indicated on the Literature review about the trapping particles capacity of vegetation, it was previously expected. On the other hand, the NO² levels were higher, in both days, outside the square,

also something that can be justified by considering the already explained connection between NO² and cars. There are high odds that the traffic in the street, which is quite constant, was causing that. The last finding was the comparison between pollutant concentrations on different areas of the square; it was visible the impact of the sky view factor on the number of particles. There are three representative SVF types, the first at the street with 87% (fig 04.23), the second spot in an area which is not covered by trees, having 92% (fig 04.24) and finally the areas which are located underneath the tree canopies, having 06% of Sky View Factor (fig 04.25). According to the already discussed effects of greenery, it is entirely understandable that the pollution levels are higher in the areas inside the garden witch are closer to the street (35ug/m³ higher, considering PM10 in the first day). This case situation happens because it is near to the pollution sources (cars, street repair and other activities happening at the measured days), and also has an area almost covered by the trees canopies, reducing wind velocities and trapping particles. And in the central regions of the square, with a higher sky view, and far from the sources, the pollutant concentration is reduced in around 40ug/m³.

Fig. 04.20 sound levels chart

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Fig. 04.21 Section with pollution levels, 23/05 (sunny day)

Fig. 04.22 Section with pollution levels, 07/06 (light rain day)

Fig. 04.23 SVF of 87%, representing spot 01

Fig. 04.24 SVF of 92%, representing spot 03

Fig. 04.25 SVF of 06%, representing spot 02

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04.3. OUTCOMES The Flume Air Quality equipment, used to gather the pollutant concentration data, can create graphs, representing and indicating the air quality of a walked path or space in which the user stayed for a more extended period. With the use of the Flume Air Quality was possible to see clearly that, during the `city of London walk`, the air quality was always indicated as `bad`, achieving alarming levels, which could generate severe health issues. In Red Lion Square, the situation shown by the equipment was of `Moderate pollution levels`, which is not so alarming but can bring health issues with long term exposure, mainly for people who already have pulmonary diseases. Later on, by walking around areas of the city, like Marylebone Road and the Regent’s park, with the tool continually measuring the air quality, there was an interesting finding which confirmed what was being stated concerning trees and pollutants. In the entire Marylebone road, the tool was indicating moderate air quality (same air quality as the Red Lion Square), in the vegetated area inside the Regents Park (with trees and grass) which was close to the roads outside, the

concentration of pollutants was higher, being indicated as ‘bad’. However, when walking to the middle of the park, which is a vast open area with much less number of trees, the air quality increased and shifted to ‘good’. The findings prove that even though the Red Lion Square is a vegetated area, it is quite exposed to pollution and is not big enough to create a ‘safe zone’ inside the city. Though it is tough to understand the factors related to air quality, with the fieldwork and its outcomes it was possible to investigate and verify some differences in air quality between a denser area with less vegetation, and an area with higher amount, like a square garden and a park (both urban integrated vegetation typologies) inside a city. Also was essential to state that until this point it wasn’t possible to see any substantial connection between the building integrated vegetation, in this case, living walls and small vegetated areas, and positive environmental improvements.

Fig. 04.26 Regents park diagram with indication of probable pollution levels in each area.

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Fig. 04.27 Continuous monitoring through air plume device,

Fig. 04.28 Continuous monitoring through air plume device,

City of London

Marylebone road and regents park.

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05. ANALYTICAL WORK

Fig. 05.1 Red Lion Square diagram of studied area

Low air quality is a reality in the big cities over the globe. Studying the most developed cities in all continents is possible to find out the issues being faced due to this global problem. Many metropoles are already working, in different intensities, to mitigate the impacts. As thoroughly explained before in the Literature Review, London is one of those cities. However, it is a fact that the air which is reaching the indoor spaces in various

locations throughout London is polluted, a situation that only gets worse while getting closer to dense areas. Sound levels are also another issue in those scenarios, and aware of these problems, the buildings are each time more enclosed, using mechanical ventilation, increasing energy consumption. Something to be considered mainly having in mind that density can grow in diverse areas of the city.

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05.1. INTRODUCTION This section of the work was conducted to investigate and define what changes, related to thermal comfort and air quality, are achievable with the application of urban and building integrated vegetation to the urban tissue of a city. The aim was also to understand if there was an urban geometry (organisation) which enhanced the effects of the greenery application, which is a significant move to investigate what are the best urban conditions to apply vegetation. It was also investigated if in London, there are conditions considered suitable for its implementation. The work was conducted mainly considering the outdoor environment, having in mind that the improved environment outside would beneficiate the indoor spaces. However, an analytical work for the indoor environment was also conducted, aiming to support and prove this assumption.

05.2. OUTDOOR WORK For the outdoor analytical work, it was decided to use a holistic microclimate modelling tool for dynamic fluid simulation called Envi-met. This software was chosen due to its capacity of developing analyses on air pollutants dispersion, solar condition and building physics (surface temperature and heat exchange processes). However, the most important feature, considering the focus of this research was the capacity of this software to develop quantified data on the impacts of green spaces and elements connected to the buildings. For those reasons, the software can proportionate comprehension of the studied scenario, facilitating the investigation of which environmental aspects are enhancing or decreasing the thermal comfort and air quality. SITE As explained before, for this section of the work there was the need to understand the impact of the site geometry (size and height of the buildings). Considering the research demand, it was substantial to choose a site that proportionated the geometrical possibility of conducting those studies.

The red lion square is an example of a widespread settlement in London, low to medium-rise buildings surrounding a ‘green pocket’. These characteristics make this site a very confident choice for the studied scenario, also having in mind that, for further analysis related to geometry and density the open area can be modified to investigate urban design approaches in the city. INPUTS For conducting the analytical work, the first decision after defining the site was to establish one day to analyse the outcomes, one hour of the day was also selected to enhance the value of the comparison studies. The area can and have reached before high levels of pollution, but as the aim of this section is to compare strategies it was interesting to understand if in a portion of the time which presented lower pollutant concentration there would still be changes between the studied scenarios. Searching the LondonAir recorded data for pollution levels in the nearest monitoring station, which is ‘Camden – Holborn (Midtown)’ it was possible to spot that in the 3rd of August of 2018 at 11 am the PM2.5 concentration was 5ug/m³, PM10 was 15.4ug/m³ and NO² concentration was 42.1ug/m³. With the aim of further investigating with lower pollution levels and considering that it was a hot sunny day, which could demonstrate the impact of vegetation in the thermal comfort, the date was selected. The average dry bulb temperature in 03/08/2018, from 11 to 12 am was 27.2°C, the prevailing wind according to the weather station was northwest with 3.72 mph speed. According to the wind rose simulated in grasshopper (fig 05.3) for the same date during the day (09 am to 09 pm), the prevailing wind was west. The wind speed observed was of over 4.0m/s during the day, in the northwest direction. For the model construction in the software, there was an attempt of reproducing the same characteristics of the square, as can be found in the site today, but also simplifying when needed to assure that the result could be understood and easily connected with the variables which were

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Fig. 05.2 Red Lion Square gardens studied area, Google maps, 2019

Fig. 05.3 Wind rose for 03/08 during the day (09 am to 09pm), overlapping the studied area

Fig. 05.4 Diagram of base model used for the Envi_met simulation

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being investigated. As mentioned before the Red Lion Square has more than one type of tree, but for the model, the one chosen was the Platanus x Hispanica species, which is the one found in a higher number. For the Envi_met, it was selected a tree which had the same characteristics, for example, the typology `CADUCIFOLY`, the size of (15m) and the high LAD. The Leaf Area Density, characteristic which was explained in the literature review, was proved to be of substantial impact on radiation and pollutant concentration. All the surrounding buildings were modelled respecting its height and sizes but in a simplified way, without openings, and with the same material applied to all buildings. For this research exercise, the selected material was concrete. The material choice was based on the aim, which was not to investigate the impact of the materials towards the environment but to spot the difference between a vegetated surface and a nonvegetated surface towards it. The living wall which was added on the building facades was using a system based on soil and aggregates (35cm) in addition to tall grass (50cm) with components from the Envi_met database. For all the different experimented scenarios, this living wall system was applied on all surfaces of the building, which is a probable exacerbation of the reality, considering the openings required for daylight and sun radiation. However, it is essential to state that there are examples over the world of vegetation applied in front of openings (which will be exemplified in the indoor analytical work section), showcasing this as a possible reality. METHODOLOGY The analytical work for this research is composed of numerous experiments related to greenery and the surrounding buildings' characteristics. The conducting of those experiments is divided into two sections, the first portion is dedicated only to the investigation of the site without changing its density and geometric characteristics, and only experimenting between the addition and subtraction of vegetation elements. The second part is dedicated to

investigating different density and building geometries on the studied site, also experimenting with the absence and presence of greenery. All simulations outputs were analysed at the height of 1.1m from the ground, considering as a height that could impact children and adults using the spaces. The main studied aspects in the simulations were the Mean Radiant Temperature (which is closer to the perception of the temperature by the user) and the pollutant concentrations (PM2.5, PM10, and NO²). To assist in the interpretation of the results, weighted averages were calculated from the results shown in the Envi_met graphs, considering only the area of the Red Lion Square. METHODOLOGY PART 01 The first step was to simulate the Red Lion Square, maintaining all the characteristics of the existant site, keeping trees and grass which are in the current scenario, with no greenery addictions. The second scenario was built adding living walls attached to the entire surfaces of the immediate surrounding buildings and subtracting the trees. The third scenario of this section was based on the decision of eliminating any typology of vegetation, leaving the square and surrounding structures without grass or trees, with only soil and cement. The two last scenarios were built to start the comparative studies between situations. There was also one previous simulation using a different type of tree, with a different Leaf area density (LAD) to confirm that the change could impact the environment. As is going to be further explained, the simulations showcased very high levels of mean radiant temperatures; for this reason, the UTCI simulation was also executed. The Universal Thermal Climate Index (UTCI) is used to measure and indicate thermal comfort, using different categories to indicate the presence or not of thermal stress; above 46°C is considered to be extreme heat stress, from 38°C to 46°C very strong, 32°C to 38°C strong heat stress and from 26°C to 32°C considered as moderate.

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Fig. 05.5 Diagram of model for Envi_met simulation with addition of green walls

Fig. 05.6 Diagram of model for Envi_met simulation with no vegetation

Fig. 05.7 Diagram of model for Envi_met simulation representing the area which will be modified and further studied

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MAIN OUTCOMES PART 01 When changing the Platanus-hispanica to another type of tree with lower LAD was possible to spot differences between the analysed mean radiant temperatures and also pollutant concentration. Understandably, the changes were positive when related to pollutants, once there is less canopy volume to trap the particles, but at the same time, it allows a higher amount of radiation to reach the ground. Comparing the current situation (fig 05.7) with the scenario with the addition of living walls and the scene with no vegetation at all it was possible to spot at first sight that the mean radiant temperature in the areas surrounding the square did not suffer any change in any of the studied cases. It was also clear to see the impact of the trees on the mean radiant temperature, considering that the weighted average showcased that the radiant temperature inside The Red Lion Square drops from 62°C to 43.2°C. It also falls when comparing the no vegetation scenario with the one with grass and living walls, dropping only 2°C, probably because of the grass, as is possible to presume from the graphs (fig 05.8 and 05.9). The UTCI simulation shown that in the ‘no vegetation’ situation there is strong heat stress (32.2°C) inside the square area, against moderate heat stress (29.8°C) with the living walls and glass additions. When analysing the current situation (with trees) the temperature drops to the weighted average temperature of 26.1°C which is in the threshold of no heat stress. The results indicate a substantial positive impact on thermal comfort whit the existence of the trees. However, it does not express any significant change on the Red Lion Square with the addition of living walls. On the other hand, studying the outcomes on the surrounding areas, with the surfaces covered with the living wall structure it was possible to see a shift in one spot(indicated in fig 05.9), dropping from an average mean radiant temperature of 66°C to a 62°C. This result is significant to suggest that in specific urban contexts (geometries) the building integrated vegetation (green walls) can modify the environmental characteristics. This finding

enhances the necessity of investigating and understanding in which contexts greenery can create impacts. This finding is also one more factor that drove the conduction of the second section of the analytical work. Analysing the pollutants concentrations, it was possible to see that even though the showcased levels for all pollutants (NO², PM2.5, and PM10) were not high, what makes sense considering the inputs for that day, it was still possible to spot differences between the scenarios. For the development of the comparison studies, the PM2.5 concentration levels were the first pollutants to be analysed. The primary visible outcome was that the weighted average which was 1.5ug/m³ in the current scenario with trees (fig 05.10), and in the situation with no vegetation at all (fig 05.11) the number drops to 0.87ug/m³, finally, after adding living wall and grass (fig 05.11) the concentration suffers an increase to 1.3ug/m³. Those outcomes are proof of what was presented in the literature review about the ‘canopy effect’ of trees or ‘trapping effect’ of vegetation in general. When analysing the graphs, it is possible to see that the spots with higher pollution levels are the same areas that showcased higher levels in the fieldwork. The wind speeds in the three different situations were also studied, displaying that the higher wind velocities were found in the ‘no vegetation’ scenarios, suffering a slight decrease with the addition of living walls, finally, decreasing even more in the scene with threes — an expected outcome which also helps to prove the higher levels of pollution mentioned before. Comparing the no vegetation and the living wall situations and further observing the surroundings of the square is possible to see in the graph with living walls and grass a slight reduction of the areas with a higher concentration of PM2.5. All these phenomenon’s can be seen happening In a very similar way to all the other outcomes of PM10 and NO².

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Fig. 05.8 Mean radiant temperature simulation result for the scenario with trees (current scenario)

Fig. 05.9 Mean radiant temperature simulation result for the scenario without any vegetation

Fig. 05.9 Mean radiant temperature simulation result for the scenario with grass and living walls in all the facades of the surrounding buildings

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Fig. 05.10 PM2.5 simulation result for the scenario with trees (current scenario)

Fig. 05.11 PM2.5 simulation result for the scenario without any vegetation

Fig. 05.12 PM2.5 simulation result for the scenario with grass and living walls in all the facades of the surrounding buildings

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METHODOLOGY PART 02 After analysing and understanding the results of section 01, there was a need to experiment with the geometries of the buildings. Investigations led by changing the density and the size, to determine if deeper proximity between the buildings and the green elements could enhance the positive impacts on thermal comfort and pollutants concentration. The methodology in this section is essential, taking into consideration the aim to improve environmental quality in already dense areas of the city. Areas like the City of London borough, or the ones which will be more dense in the future with the city development. All of the design experiments were conducted respecting the size of the present square, only ‘building inside this area, maintaining the size of the streets. The size of the surrounding buildings was also kept the same in all the case scenarios, maintaining the same context in all simulations. The literature review related to density parameters and the density studies presented in the fieldwork section were considered to design different scenarios for the geometry study. As mentioned before the plot ratio of the area, which includes the square and the immediate surrounding is 03, the site coverage of 42% and the vegetated area of 12% against 10 of plot ratio, 52% covered area and 3% green area on the City of London. For each scenario with different geometry, two simulations were executed, one with no vegetation at all and another with the addition of the greenery decided for each situation. The development of these cases made it possible to develop comparison studies between the existence of greenery. The trees added in all scenarios were always of the same type. Based on this background, the Red Lion Square gardens plot was divided into eight pieces with the same size each. After that, the decision was to start occupying the site, starting first with plot ratio 01 (fig 05.14), which was leading to only 25% of the site coverage. As the design experiment had the aim of understanding consequences in an area with higher built site coverage and less vegetated area, a plot ratio of 02 was determined, leading to a

Fig. 05.13 Diagram of site division for density studies

Fig. 05.14 Diagram of site with plot ratio 1.0 and site coverage of 25%

Fig. 05.15 Diagram of site with plot ratio 2.0 and site coverage of 50%

Fig. 05.16 Diagram of site with plot ratio 2.0 and site coverage of 37.5%

Fig. 05.17 Diagram of site with plot ratio 2.0 and site coverage of 25%

Fig. 05.18 Diagram of site with plot ratio 2.0 and site coverage of 12.5%

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50% site coverage and 50% vegetated area. Based on these parameters, the first simulated scenario was developed, composed of four buildings with 04 floors and 11.2 m height each, with 13 m between buildings (fig 05.19). In this case for the scenario with vegetation, living walls and grass (in the open areas) were added. After achieving a high site coverage, the second step was to reduce it to observe the outcomes, but maintaining the same density level, in other words, keeping the plot ratio, which was held in all investigated scenarios. Considering the study aim, the second scenario was developed with 37.5% site coverage, displaying three buildings in total, two with 14m height and one in the centre with 16.8m, there as a space between buildings of 28m (fig 05.20). For the scenario with vegetation, besides the living wall and grass, four threes were added, two on each open space between buildings. The addition of trees was made to understand the relation between typologies of greenery and the new geometries. The step after was to continue reducing the site coverage, this time to understand the relationship between buildings as barriers to pollution sources and the possibility of a ‘protected’ bigger green area. Following this thought, the third scenario was built with only two buildings with 22 m height and a square in the middle, creating a space of 68m between buildings (fig 05.21). For the scenario with vegetation, six trees were added in the centre. To compare the effect of barriers against the impact of open spaces related to the pollutant concentration, the next scenario was developed. The fourth case study consisted of one unique building on the right side of the site, far from the primary source (Drake Street). The building presented 44m height, which was higher than all the structures of the immediate surrounding, and closer to the height observed in the City of London, leaving an open space of 78m from the tower to the main street (fig 05.22). For the vegetated scenario, only four trees were added, close to the building with a distance of around 40 m from Drake street, leaving an open area, with no vegetation obstruction which could trap pollution particles.

Fig. 05.19 Diagram of the first studied scenario

Fig. 05.20 Diagram of the second studied scenario

Fig. 05.21 Diagram of the third studied scenario

Fig. 05.22 Diagram of the fourth studied scenario

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After these previous experiments, to fulfil the need for more in-depth investigation, a study started to be developed considering the first option of site coverage (50%). The fifth scenario was modelled based on the conception of a ‘courtyard building’ which presented an open space in the middle (the courtyard), considering that it would be disconnected from the outside area, consequently the pollution sources. This scenario presented 58.2% site coverage being a unique building in “O” shape, having a height of 8.4 m in the right portion and 11.2m (one additional floor) on the left part, keeping the ‘2’ plot ratio and creating a higher barrier closer to the main street (fig 05.23).

The final studied scenario was designed from the need to investigate what would happen with the quality of the courtyard environment if it was not completely disconnected from the outside spaces (pollution sources). The sixth case study was composed of two buildings in ‘U’ shape, having an open area in the middle of the courtyard, in this scenario both buildings having 11.2 m height (fig 05.24). The apertures were made to keep the urban area more permeable to the population but also keeping a distance from the main road. This scenario had two investigative situations with vegetation, one only with living walls and grass and the last one with the addition of five trees.

Fig. 05.23 Diagram of the fifth studied scenario

Fig. 05.24 Diagram of the last studied scenario

Fig. 05.25 Diagram of the first studied scenario

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MAIN OUTCOMES PART 02 Comparing the first two studied designs with vegetation (living wall, grass, and trees in the second scenario) the first one (fig 05.26) presented a weighted average mean radiant temperature of 55°C against 50.4°C on the second (fig. 05.27), which also displays a slight increase in the PM2.5 concentration. Even though the building geometry acts as a barrier against the pollution sources, as expected, the scenario with trees has lower air quality inside the areas between buildings. It was interesting to observe that the reduction between scenarios was the same from between the scenes in the first section of the work, the current situation of red lion square and the case with living walls and grass, with a drop of around 0.2ug/m³. The studies with two buildings (fig 05.28) and one building (fig 05.29) showcased that, talking about weighted average pollution concentrations, the existence of a barrier or an open space can be used to decrease the levels in a public square. This fact states the importance of observing that the open area without trees in the hot period of the year will always present lower comfort levels than the area with trees. Having this in mind it is possible to affirm that the situation with two buildings is more efficient to bring thermal comfort and a ‘protected space’ with higher air quality. Until this point, after analysing the outcomes of all the 04 different scenarios with and without vegetation for mean radiant temperature, wind velocities and pollutants concentration (NO², PM10, and PM2.5), it was very clear that the addition of living walls and grass in all scenarios did not generate significant differences in thermal comfort and air quality. With the addition of trees, all the experimented geometries showcased higher thermal comfort and lower air quality. Whit, the implementation of the courtyard building (fig 05.30), was possible to see that the air quality inside the enclosed courtyard suffered substantial enhancement, presenting a weighted average of 0.4ug/m³, the lowest concentration from all outcomes. Comparing the scenarios with and without vegetation in the courtyard building case study, the first result was a drop in the mean radiant temperature of 6°C when the living walls

and grass were added. Also was possible to see that the pollution level continues to be precisely 0.4ug/m³, being the first situation where the vegetation didn’t increase even slightly the number of particles. This outcome proves that the building geometry can generate sheltered areas, even in city centres where Urban and building integrated vegetation can be added without fearing air quality decreases. The changes in thermal comfort can be related to the vegetation and also to the building geometry, which is shading the courtyard, decreasing the surface temperature and consequently the mean radiant temperature. The ‘U’ shaped structure (fig 05.31) showcased a weighted average PM2.5 concentration level of 0.7ug/m³, only 0.3 higher than the wholly enclosed building (scenarios with grass and living walls). The apertures to the courtyard, probably due to the permitted wind circulation, considering that the prevailing winds come from the southwest, reduced the mean radiant temperature in 2°C and wiped out the pollutants particles. These findings display the creation of a scenario in the middle of the city, with much lower pollution levels than the surroundings without harming the urban permeability. The last issue in this scenario was still the high mean radiant temperatures, decreasing thermal comfort. For this reason, the last step was to add trees inside the open space (fig 05.32). With this move, it was possible to see that the PM2.5 concentration only increased 0.05ug/m³, indicating no substantial change in the air quality. On the other hand, the mean radiant temperature drops from 51.3°C to 38.5°C, exactly 12.8°C difference; this showcases an absurd change in thermal comfort. The last studied scenario presents a very successful strategy between the building geometry design and vegetation application towards increasing thermal comfort and air quality at the same time. Those achievements also indicate that all the facades facing the courtyard can have apertures, naturally ventilating the indoor spaces without the concern about pollution and, according to the literature review, even noise levels would decrease, considering the barrier that the building mass plus vegetation can create against sources

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Fig. 05.26 Diagram of the first studied scenario with vegetation

Fig. 05.27 Diagram of the second studied scenario with vegetation

Fig. 05.28 Diagram of the third studied scenario with vegetation

Fig. 05.29 Diagram of the fourth studied scenario with vegetation

Fig. 05.30 Diagram of the fifth studied scenario with vegetation

Fig. 05.31 Diagram of the last studied scenario with vegetation

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Other analysed factor was the difference in the surfaces temperatures between scenarios. It was possible to spot in all situations with the application of living walls that the temperature of the building facades facing south always suffered a drop of more than 10C. The facades facing east and west also experienced a lower reduction in the

temperature (3.5 to 5C) This finding shows how the application of living walls can cool the temperature of the surfaces and consequently the resultant temperature of the area.

Fig. 05.32 Diagram of the last studied scenario with vegetation in additional trees

Fig. 05.33 Results of the surface temperature simulation in the scenario without vegetation

Fig. 05.34 Results of the surface temperature simulation in the scenario witht grass and living walls

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05.3. INDOOR WORK For the indoor analytical work, it was used a thermal analysis software, called TAS Engineering. This software was chosen because it’s capable of providing thermal analysis of the indoor environments, including resultant temperature results. In this work, the software was used to emulate the existence of vegetation attached to the building façade or close to the openings, to investigate the possible impacts towards the indoor environment. LIMITATIONS It is essential to state that simulations with vegetation are very uncommon with this type of software, since plants are living beings, which the properties and characteristics are continually changing, making it not possible to consider it as a material with a constant U-value or even a regular size. Consequently, the studies conducted on TAS were based on hypothetical conditions that the addition of plants can provide. It is possible to state that the studies conducted with this software are an emulation of a situation with greenery and not an exact representation of the reality.

resultant temperatures prioritising two different dates. The principal investigated dates were the fourth of February, indicated by weather spark as being one of the coldest days of the year, having temperatures from 4°C to 8°C. The other analysed day was the first of august considered by the same font as being one of the hottest days, presenting temperatures between 17°C to 26°C. It is essential to state that London can and usually showcase lower and higher temperatures in some moments over the year. However, the days were chosen to have in mind that the shown temperatures are closer to the reality of summer and winter periods in London.

SITE As the outdoor work was conducted in the Red Lion Square Gardens, for the indoor analysis, the aim was to select a building in the same area. For this reason, a building, which is a low rise residential building, was chosen, serving as an example of the oldest typology in the area. From the selected structure, a specific floor, in the middle of the building, was selected. The chosen level was modelled without internal divisions, considering the openings on the external walls as a simple “shoebox” model for simulation. METHODOLOGY For the development of this section, the analysis was made considering three different scenarios, each scenario aiming to represent one way which the vegetation could impact the indoor environment, always having in mind the limitations of this software concerning greenery. For all the studied situations, the main analysed factor was the

Fig. 05.35 Diagram with the location of the studied area

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The first case was developed to investigate the effects that a living wall structure can generate, considering that the layers added to the building façade would change its U-value. For this first exercise was essential to find a living wall structure that was being used and applied in reality, what lead the selection of the green wall system produced by “Biotec”. The company was responsible for the instalment of the ‘walkie talkie’ building living wall, which was mentioned before in the fieldwork section. The Biotec living wall system (fig 05.36) is composed by the existent wall, a waterproof backing board, to protect against water infiltration, a drainage layer, a structure for the instalment of the plants and finally the greenery. The plants used in this system are hydroponic and usually planted in stone wool or rock wool.

Fig. 05.36 Living wall system by Biotec, Biotec 2019

For the modelling in the software, this structure was transformed into a simplified system (fig 05.37), consisting of 03 layers, existing wall, the waterproof backing board, and the rock wool. A research on the different characteristics of these materials, like conductivity, emissivity, and convection capacities, was conducted, and with the input of those values the U-value of the structure shifted from 0.36 W/m².°C to 0.30 W/m².°C. The second experiment was based on the possibility of installing a structure with vegetation in front of the openings, what would work as ‘shading elements’. This case studied is based in existent examples of this use of vegetation, like the ‘Bosco verticale’ mentioned before in the literature review and also the Centre for Interactive Research on Sustainability, which has the project of a propper living wall system applied in front of the windows (fig 05.38). To emulate this scenario in the software, ‘fins’ were used as shading elements. The fins were modelled, with values based on the plants' emissivity, conduction and convection and other characteristics which were possible to serve as an input, aiming to bring the emulation as close as possible to the reality. The third and last scenario was built based on the understanding of the cooling effect that vegetation can generate through evapotranspiration. As there was no access to a

Fig. 05.37 Simplified living wall system for simulation with living wall applied in front of windows

Fig. 05.38 Centre for Interactive Research on Sustainability, PWL paternship 2018 with living wall applied in front of windows

representative formula of the specific process, concerning the cooling capacity of evapotranspiration, the passive evaporative cooling method, based on the PhD research `The

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development of Passive Downdraught Evaporative Cooling` by Rosa Schiano-Phan, was applied. The work mentioned before is related to the understanding of the capacity of cooling the environment with the use of water dispersion. Considering that in the evapotranspiration process, there is a release of water particles, it made sense the use of the same formula to represent it. The strategy consists in the creation of a ‘dummy’ supply zone with different temperature characteristics, built-in front of the apertures (fig 05.39). The area exists to emulate the existence of vegetation in front of the windows (fig 05.40). The formula is used to mimic the evaporative cooling which would modify the temperatures in the area. The formula is Ts = Twb + 2°C, where Ts is the “dummy zone” and Twb is wet bulb temperature.

Fig. 05.39 Sketch representing the inputs for emulation of evapotranspiration cooling with living wall applied in front of windows

The second and third build scenarios were only studied in the summer period, considering that the vegetation will not be ‘alive’, consequently present in this period

Fig. 05.40 Section sketch representing the inputs for emulation of evapotranspiration cooling with living wall applied in front of windows

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MAIN OUTCOMES For each case studied was possible to develop graphs which lead to the idea of the impacts. It is essential to state that, due to the experimental character of the research, only the resultant temperature was analysed. The studied “shoebox” is a fictitious context where the internal heat gains, from occupant, equipment and lighting were not considered. The resultant temperature analysis was deemed to be fit for the understanding of thermal comfort inside the studied area. In the first studied scenario, which was evaluating the impact trough the enhancement of the U value, when comparing the situations with and without vegetation, it is not possible to spot

any considerable change on the resultant temperatures. This finding is probably because the difference between U-values was meagre (around 6 W/m².°C). The results showed that the applied system does not generate a high enhancement of the material against the outside environment, not providing a significant change in thermal comfort for the inhabitants. However, it is spotted that the temperatures in the summer day (fig 05.41) dropped in almost all hours of the day ( less than 1°C). For the day analysed in the winter (fig 05.42), the temperatures were also enhanced in less than 1°C for all the hours of the day. The explained findings can also be an indication of the possible positive outcome that another system of living wall could bring towards comfort.

Fig. 05.41 Graph of resultat temperature in the fourth of February (winter period) with the base case scenario and the scenario considering the new Uvalue with the green wall with living wall applied in front of windows

Fig. 05.42 Graph of resultant temperature in the first of august (summer period) with the base case scenario and the scenario considering the new U-value with the green wall with living wall applied in front of windows

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The second studied case, which was the emulation of the impacts of plants acting like shading elements, showcased a difference of 2°C in almost all analysed hours in the resultant temperature (fig 05.43). This result is more expressive, considering that a difference in resultant temperatures from 27°C to 25°C in the hottest period of the day can mean a significant change in comfort for the inhabitants. It is an expected outcome having in mind the positive impacts that shading elements usually brings in summer periods. The considerations are based on the fact that one of the facades is facing south, having direct sun radiation the entire day, which is reduced with the plants as “fins”.

evapotranspiration, there was an even higher difference between the temperatures. It was possible to spot differences of 3°C in some hours, however, only during the night period (from around 8 pm to 6 am) that it was possible to see changes (fig 05.43). The results prove that, using the evaporative cooling formula, the passive cooling strategy can increase comfort indoor in summer. It is essential to state that further investigations are fundamental for a more in-depth understanding of the potential of Urban and built integrated vegetation. The use of more instruments, as fieldwork or different softwares and more research time, can enlight even more the study in this section.

Finally, for the third and last scenario, which was related to the cooling effect trough

Fig. 05.43 Graph of resultant temperature in the first of august (summer period) with the base case scenario and the scenario considering the plants as shading elements with living wall applied in front of windows

Fig. 05.44 Graph of resultant temperature in the first of august (summer period) with the base case scenario and the scenario considering the cooling of plants through evapotranspiration with living wall applied in front of windows

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06. OUTCOMES AND DESIGN APPLICABILITY

Fig. 06.1 Diagram of British museum area with the application of living walls in the facades

The entire analytical work section is developed based on a selected site, considering the geometry (density), and local pollution levels inputs. For this reason, it is evident that the results are going to be linked with the climate conditions of the town combined with the local data. If the research aim is to prove or showcase a situation that is probably happening throughout the city, it is essential that the chosen site can be a representation of other areas. For this work, the representation is trough the Red Lion Square Gardens and the City of London, which has been intensely discussed in this

research. Both sites and also developed case scenarios displayed typical urban settlements all over London, which means that the outcomes and studied strategies can probably be applied in several situations with the same climate characteristics. For this application to be viable, this work aimed to develop guidelines for future design interventions of ‘good practices’ related to Urban and Building integrated vegetation. This section has the aim to define where are the best contexts to use the greenery, and what type should be applied in each setting.

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06.1. OUTCOMES Based on the main findings for the outdoor and indoor studied scenarios is possible to affirm that the more considerable impacts related to thermal comfort were associated with the use of living walls in situations with less distance between buildings. As soon as the distance between buildings started to increase the positive impacts began to lower, sometimes even not being possible to spot any difference. Another critical factor proved in this work was the fact that trees are elements that trap pollutant particles, decreasing the air quality of the area it is implemented if the trees are close to the pollution sources. However, it is essential to state the enormous impact that trees bring towards thermal comfort in all situations which it was applied. The need for having a wind flux to ‘clean’ the areas from pollution particles was also an important finding. It was essential to conclude that living walls or green pockets close to apertures can increase the thermal comfort inside in summer periods, which is valuable considering the indication of a hotter climate in the future. However, the main finding is probably the understanding of how the building geometries, like courtyard buildings, can act as barriers, increasing the possibility of having vegetated spaces inside dense environments. The “protected” green environments inside the city could have much lower levels of pollution, higher thermal comfort in hotter days and probably lower noise levels. This research has shown that the implementation of trees in enclosed spaces is a very assertive strategy to achieve higher levels of thermal comfort without compromising air quality at the ground level area, which was the studied subject of this work. It is also visible the importance of urban parks of medium to big scale thermal comfort and air quality regulation inside cities

06.2. DESIGN APPLICABILITY There is a significant number of the courtyard in London and also narrow streets, which would probably be very effective concerning the air quality and thermal comfort increase for the application of living walls. There is a factor not considered in this work, which is the money spent on the installation of living walls. The monetary factor is a limitation which was not profoundly discussed based on the experimental character of this research. For this reason, it is challenging to determine a proper area or even the structure of existing buildings where the building-integrated vegetation should be installed. However, with all the discussed points in this research, it is possible to have an idea of the energy consumption decrease that the material application could cause. Based on the outcomes, it is possible to state that applying green walls extensively in narrow streets inside dense settlements would enhance thermal comfort in these areas. According to the analytical work findings, for the effectiveness of these strategies, the distance between facades shouldn’t be higher than 20m. This size of roads are widespread in London neighbourhoods, and even though local studies should be developed for each area of application this works indicates that would be positive to use this strategy in London. Due to the findings of this work, it can also be possible to suggest that scattered trees close to significant avenues can also be bad decisions related to air quality. When talking about trees, as mentioned before is possible to affirm that areas with barriers from the pollution sources, or further from it are the best environments for its application.

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Fig. 06.2 Sketch of the “guidelines� in relation to the work findings

Fig. 06.3 Diagram of the City of London area with the application of living walls in the facades

Fig. 06.4 Diagram of the St Pauls Catedral area with the application of living walls in the facades

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07. CONCLUSION This research enlightened the essential character of green elements towards physical and psychological health of people. It also brought issues related to density, thermal discomfort and air quality which vegetation can help to mitigate, considering its limitations. Further investigating London, it is also highlighted the urgency in dealing with population growth in the city, mainly when analysing the built environment and the consequential problems. The research shows the difficulties of measuring vegetation impacts and which effect can be already seen from field analysis as the poor outcome of trees when related to pollution — further proving this result trough digital simulations, showcasing reductions of 1.5ug/m3 to 0.87ug/m3 with the subtraction of trees. It is also displayed in this work the importance of trees for thermal comfort with reductions of over 12C in the mean radiant temperature in one of the case studies. The effect of different urban designs and settlements is also highlighted, in some scenarios displaying pollutant reductions of 1.2ug/m3. It clarifies how vegetation can have negative or no impacts at all considering air quality or also no effects or positive outcomes considering thermal comfort depending on which settlement is inserted. It is fundamental to conclude this research stating that Urban and Building Integrated Vegetation can be the solution for densifying cities, which as a natural process for towns as London, creating a better environment. UBIV`s can also be powerful when aiming the enhancement of the city with the present configuration.

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08. LIST OF FIGURES Fig. 0 The environmental perspective of one of the studied scenarios. Fig. 01.1 Semaphore Project (Vincent Callebaut Architectures, 2019) Fig. 02.1 London with applied greener, Living green city 2018 Fig. 02.2. Plot Ratio = 01 and site coverage = 25%, Vicky Cheng 2019 Fig. 02.3 Plot ratio = 0.5 and site coverage = 25%,, Vicky Cheng 2019 Fig. 02.4 Layout study 01, Vicky Cheng 2019 Fig. 02.5 Layout study 02, Vicky Cheng 2019 Fig. 02.6 Layout study 03, Vicky Cheng 2019 Fig. 02.7 Pollution sources, WHO Europe Fig. 02.8 PM sizes, US EPA 2018 Fig. 02.9 Heath island effect, Jolma Architects, 2018 Fig. 02.10 Living wall - Edgware tube station, Biotecture, 2011 Fig. 02.11 Vertical Forest - Skyscraper complex, Buro Ole Schereen 2017 Fig. 02.12 Living roof - New providence wharf, Zinco 2012

Fig. 03.8 Smog in London, Kathy deWitt/Alamy, 2019 Fig. 03.9 NO2 levels in London, LAEI, 2016 Fig. 03.10 Map of London only displaying rivers and vegetation, GIGL, 2014 Fig. 03.11 Map of London boroughs, Hidden London, 2012 Fig. 03.12 Birdview of the City of London borough, mail online, 2018 Fig. 03.13 Red Lion Square gardens Fig. 03.14 Density study – City of London Fig. 03.15 Density study – Red Lion Square Gardens area Fig. 04.1 Red lion square diagram of pollution levels Fig. 04.2 Map of the measured spots in the City of London borough, google maps, 2019 Fig. 04.3 Spot 03, 2019 Fig. 04.4 Spot 04, 2019 Fig. 04.5 Spot 09, 2019 Fig. 04.6 Spot 05, 2019 Fig. 04.7 Spot 07, 2019 Fig. 04.8 Spot 12, 2019 Fig. 04.9 PM 2.5 levels chart

Fig. 02.13 Square Garden - Woburn square Fig. 04.10 PM 10 levels chart Fig. 02.14 Bosco Verticale, Bios 2018 Fig. 04.11 NO2 levels chart Fig. 02.15 Woburn square, Bloomsburry square and gardens, 2018

Fig. 04.12 sound levels chart

Fig. 02.16 Bedford square, Bloomsburry square and gardens, 2018

Fig. 04.13 Map of measured spots Red Lion Square gardens

Fig. 02.17 Red Lion Square gardens, Bloomsburry square and gardens, 2018

Fig. 04.14 Spot 01, 2019

Fig. 03.1 London tourist map, trip indicator, 2018 Fig. 03.2 London wind rose Fig. 03.3 Psychometric chart – London present (2018) Fig. 03.4 Psychometric chart – London future (2050) Fig. 03.5 London Temperature graph (K) 2050 Fig. 03.6 London Temperature graph (K) 2019 Fig. 03.7 London cumulative rainfall graph

Fig. 04.15 Spot 02, 2019 Fig. 04.16 Spot 03, 2019 Fig. 04.17 Spot 11, 2019 Fig. 04.18 Spot 12, 2019 Fig. 04.19 Spot 13, 2019 Fig. 04.20 sound levels chart Fig. 04.21 Section with pollution levels, 23/05 (sunny day)

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Fig. 04.22 Section with pollution levels, 07/06 (light rain day)

Fig. 05.14 Diagram of site with plot ratio 1.0 and site coverage of 25%

Fig. 04.23 SVF of 89%, representing spot 01

Fig. 05.15 Diagram of site with plot ratio 2.0 and site coverage of 50%

Fig. 04.24 SVF of 92%, representing spot 03 Fig. 04.25 SVF of 06%, representing spot 02

Fig. 05.16 Diagram of site with plot ratio 2.0 and site coverage of 37.5%

Fig. 04.26 Regents park diagram with an indication of probable pollution levels in each area.

Fig. 05.17 Diagram of site with plot ratio 2.0 and site coverage of 25%

Fig. 04.27 Continuous monitoring through air plume device,

Fig. 05.18 Diagram of site with plot ratio 2.0 and site coverage of 12.5%

City of London

Fig. 05.19 Diagram of the first studied scenario

Fig. 04.28 Continuous monitoring through air plume device,

Fig. 05.20 Diagram of the second studied scenario

Marylebone road and regents park. Fig. 05.1 Red Lion Square diagram of studied area Fig. 05.2 Red Lion Square gardens studied area, Google maps, 2019 Fig. 05.3 Wind rose for 03/08 during the day (09 am to 09 pm), overlapping the studied area Fig. 05.4 Diagram of the base model used for the Envi_met simulation Fig. 05.5 Diagram of model for Envi_met simulation with addition of green walls Fig. 05.6 Diagram of model for Envi_met simulation with no vegetation Fig. 05.7 Diagram of model for Envi_met simulation representing the area which will be modified and further studied Fig. 05.8 Mean radiant temperature simulation result for the scenario with trees (current scenario) Fig. 05.9 Mean radiant temperature simulation result for the scenario without any vegetation

Fig. 05.21 Diagram of the third studied scenario Fig. 05.22 Diagram of the fourth studied scenario Fig. 05.23 Diagram of the fifth studied scenario Fig. 05.24 Diagram of the last studied scenario Fig. 05.25 Diagram of the first studied scenario Fig. 05.26 Diagram of the first studied scenario with vegetation Fig. 05.27 Diagram of the second studied scenario with vegetation Fig. 05.28 Diagram of the third studied scenario with vegetation Fig. 05.29 Diagram of the fourth studied scenario with vegetation Fig. 05.30 Diagram of the fifth studied scenario with vegetation Fig. 05.31 Diagram of the last studied scenario with vegetation Fig. 05.32 Diagram of the last studied scenario with vegetation in additional trees

Fig. 05.9 Mean radiant temperature simulation result for the scenario with grass and living walls in all the facades of the surrounding buildings

Fig. 05.33 Results of the surface temperature simulation in the scenario without vegetation

Fig. 05.10 PM2.5 simulation result for the scenario with trees (current scenario)

Fig. 05.34 Results of the surface temperature simulation in the scenario with grass and living walls

Fig. 05.11 PM2.5 simulation result for the scenario without any vegetation

Fig. 05.35 Diagram with the location of the studied area

Fig. 05.12 PM2.5 simulation result for the scenario with grass and living walls in all the facades of the surrounding buildings

Fig. 05.37 Simplified living wall system for simulation

Fig. 05.13 Diagram of site division for density studies

Fig. 05.36 Living wall system by Biotec, Biotec 2019

Fig. 05.38 Centre for Interactive Research on Sustainability, PWL partnership 2018 Fig. 05.39 Sketch representing the inputs for emulation of evapotranspiration cooling

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Fig. 05.40 Section sketch representing the inputs for emulation of evapotranspiration cooling Fig. 05.41 Graph of resultant temperature in the fourth of February with the base case scenario and the scenario considering the new U-value with the green wall Fig. 05.42 Graph of resultant temperature in the first of august (summer period) with the base case scenario and the scenario considering the new U-value with the green Fig. 05.43 Graph of resultant temperature in the first of august (summer period) with the base case scenario and the scenario considering the plants as shading elements Fig. 05.44 Graph of resultant temperature in the first of august (summer period) with the base case scenario and the scenario considering the cooling from plants through evapotranspiration Fig. 06.1 Diagram of British museum area with the application of living walls in the facades Fig. 06.2 Sketch of the “guidelines� in relation to the work findings Fig. 06.3 Diagram of the City of London area with the application of living walls in the facades Fig. 06.4 Diagram of the St Pauls Catedral area with the application of living walls in the facades

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10

APPENDICES

10.1. ENVI_MET SIMULATION RESULTS GRAPHS

01. Mean radiant temperature result for the 04 buildings scenario without vegetation

02. PM2.5 result for the 04 buildings scenario without vegetation

03. Mean radiant temperature result for the 04 buildings scenario with vegetation

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04. PM2.5 result for the 04 buildings scenario with vegetation

05. Mean radiant temperature result for the 03 buildings scenario without vegetation

06. PM2.5 result for the 03 buildings scenario without vegetation

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07. Mean radiant temperature result for the 03 buildings scenario with vegetation

08. PM2.5 result for the 03 buildings scenario with vegetation

09. Mean radiant temperature result for the 02 buildings scenario without vegetation

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10. PM2.5 result for the 02 buildings scenario without vegetation

11. Mean radiant temperature result for the 02 buildings scenario with vegetation

12. PM2.5 result for the 02 buildings scenario with vegetation

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13. Mean radiant temperature result for the 01 building scenario without vegetation

14. PM2.5 result for the 01 building scenario without vegetation

15. Mean radiant temperature result for the 01 building scenario with vegetation

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16. PM2.5 result for the 01 building scenario with vegetation

17. Mean radiant temperature result for the courtyard building scenario without vegetation

18. PM2.5 result for the courtyard building scenario without vegetation

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19. Mean radiant temperature result for the courtyard building scenario with vegetation

20. PM2.5 result for the courtyard building scenario with vegetation

21. Mean radiant temperature result for the U building scenario without vegetation

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22. PM2.5 result for the U buildings scenario without vegetation

23. Mean radiant temperature result for the U building scenario with vegetation

24. PM2.5 result for the U buildings scenario with vegetation

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25. Mean radiant temperature result for the U building scenario with vegetation and additional trees

26. PM2.5 result for the U buildings scenario with vegetation and additional trees

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University of Westminster, College of Design, Creative and Digital Industries School of Architecture and Cities MSc Architecture and Environmental Design 2018/19 Sem 2&3 Thesis Project Module

Joao Silva September 2019 London, United Kingdom

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