A Quantitative Method for Evaluation of Visual Privacy in Residential Environments

With the rapid expansion of high-rise and high-density buildings in urban areas, visual privacy has become one of the major concerns affecting human environmental quality. Evaluation of residents’ visual exposure to outsiders has attracted more attention in the past decades. This paper presents a quantitative indicator; namely, the Potential Visual Exposure Index (PVEI), to assess visual privacy by introducing the damage of potential visual incursion from public spaces and neighborhoods in high-density residences. The method for computing the PVEI mainly consists of three steps: extracting targets and potential observers in a built environment, conducting intervisibility analysis and identifying visible sightlines, and integrating sightlines from building level and ground level to compute the PVEI value of each building opening. To validate the proposed PVEI, a case study with a sample building located at the center of Kowloon, Hong Kong, was evaluated. The results were in accordance with the common-sense notion that lower floors are subjected to poor visual privacy, and privacy is relatively well-preserved in upper floors in a building. However, residents of middle floors may suffer the worst circumstances with respect to visual privacy. The PVEI can be a useful indicator to assess visual privacy and can provide valuable information in architectural design, hotel room selection, and building management.

Download Full-text

Examining the associations between urban built environment and noise pollution in high-density high-rise urban areas: A case study in Wuhan, China

Sustainable Cities and Society ◽

10.1016/j.scs.2019.101678 ◽

2019 ◽

Vol 50 ◽

pp. 101678 ◽

Cited By ~ 10

Author(s):

Man Yuan ◽

Chaohui Yin ◽

Yi Sun ◽

Weiqiang Chen

Keyword(s):

Built Environment ◽

Urban Areas ◽

Noise Pollution ◽

High Density ◽

High Rise

Download Full-text

High-rise in trouble? Learning from Europe

Journal of Place Management and Development ◽

10.1108/jpmd-12-2015-0058 ◽

2016 ◽

Vol 9 (2) ◽

pp. 224-240 ◽

Cited By ~ 2

Author(s):

Paul van Soomeren ◽

Willemijn van de Klundert ◽

Inés Aquilué ◽

Justin de Kleuver

Keyword(s):

Fear Of Crime ◽

Architectural Design ◽

Ground Level ◽

Le Corbusier ◽

Content Type ◽

Learning Capacity ◽

High Rise ◽

The Usa ◽

History Of ◽

High Level

Purpose All over the world, millions of people live in buildings and neighbourhoods that follow the principles of Congrès International d’Architecture Moderne (CIAM) and Le Corbusier: high-rise “residential machines” in parks reminiscent of green seas. Some of these have become very successful living environments, but in Europe and the USA, several neighbourhoods featuring this architectural design dream have become a social nightmare. Residents who were able to moved to more desirable neighbourhoods. This led to a high level of vacancy and crime and fear of crime have flourished, resulting in a stigma that is often long-lasting and difficult to repair. The pupose of this study is to learn from these experiences. Design/methodology/approach In this paper, two high-rise neighbourhoods, built in a Corbusier-like fashion and situated on the outskirts of major cities, are put under the evaluation spotlight: Bijlmermeer: located in Amsterdam, The Netherlands, with an abundance of landscaping, shrubbery, green fields and one high-density neighbourhood; and Bellvitge: located in Barcelona, Cataluña, Spain, looking less like a park and more like a city with open-air parking on ground level, and many small shops, bars and restaurants. Findings Both neighbourhoods faced enormous problems from crime, incivilities, disorder and drug abuse. Fear of crime and feelings of insecurity were high. Both governments reacted by investing huge sums of money. In Bellvitge, the investment was mainly in public transport, the public domain and new approaches in policing while keeping the high-rise buildings intact. In Bijlmermeer, a large regeneration project supported the demolition of two-thirds of all apartments and the neighbourhood was rebuilt in a low-rise fashion. Research limitations/implications This paper outlines the history of both neighbourhoods and describes the solutions that were implemented. Important lessons can be learned regarding current high-rise neighbourhoods and about the learning capacity of urban designers and planners regarding urban management. Practical implications The paper suggests that urban planners, designers and managers are slow in learning from earlier mistakes. The hypothesis is that there is no clear method available to evaluate new urban planning designs by incorporating lessons from the success or failure of previous cases. This paper focuses on density, ownership and design to identify possible approaches to evaluate new high-rise estate plans. Originality/value The Western high-rise “wave” has faded away but nowadays has become a high-rise “tsunami” in Asia. Learning from European experience may be beneficial.

Download Full-text

Urban renewal based wind environment at pedestrian level in high-density and high-rise urban areas in Sai Ying Pun, Hong Kong

IOP Conference Series Materials Science and Engineering ◽

10.1088/1757-899x/264/1/012014 ◽

2017 ◽

Vol 264 ◽

pp. 012014

Author(s):

J W Yao ◽

J Y Zheng ◽

Y Zhao ◽

Y H Shao ◽

F Yuan

Keyword(s):

Hong Kong ◽

Urban Renewal ◽

Urban Areas ◽

High Density ◽

Wind Environment ◽

High Rise

Download Full-text

A Computer-Aided Evaluation Tool for the Visual Aspects in Architectural Design for High-Density and High-Rise Buildings

CAAD futures 1997 ◽

10.1007/978-94-011-5576-2_27 ◽

1997 ◽

pp. 345-356

Author(s):

Thomas S. P. Li ◽

Barry F. Will

Keyword(s):

Architectural Design ◽

High Density ◽

Evaluation Tool ◽

High Rise ◽

Computer Aided

Download Full-text

Wind and the city: An evaluation of San Francisco’s planning approach since 1985

Environment and Planning B Urban Analytics and City Science ◽

10.1177/0265813515607474 ◽

2016 ◽

Vol 44 (1) ◽

pp. 10-32 ◽

Cited By ~ 4

Author(s):

Hyungkyoo Kim ◽

Elizabeth Macdonald

Keyword(s):

San Francisco ◽

Urban Form ◽

Urban Areas ◽

Ground Level ◽

High Density ◽

Speed Ratio ◽

Negative Effects ◽

Westerly Winds ◽

Wind Currents ◽

The City

In 1985, San Francisco adopted a downtown plan on ground-level wind currents intended to mitigate the negative effects of wind on pedestrians’ perceived comfort in public open spaces. The plan mandates that new buildings in designated parts of the city associated with high density or development potential be designed or adopt measures to not cause wind in excess of accepted comfort levels. This study examines whether and to what degree the plan has successfully shaped an urban form that mitigates wind by comparing the ground-level wind environment in 1985 and 2013. A series of wind tunnel tests found that during San Francisco’s windiest season when the westerly winds are prevalent, the overall mean wind speed ratio measured at 318 locations in four areas of the city dropped by 22%. However, there still exist many excessively windy places that are associated with specific urban form conditions, including streets oriented to have direct exposure to westerly winds, flat façades on high-rise buildings, and horizontal street walls where building façades align. Recommendations based on the findings include incorporating more tangible guidance on the built form conditions, expanding the plan’s reach to cover more parts of the city, and learning from strategies used elsewhere. By evaluating the urban form impacts of a wind mitigation policy that has been in place for 30 years, the research offers insights for other cities that have implemented or plan to adopt similar approach and sheds light on issues related to wind comfort in high-density urban areas.

Download Full-text

Urbanization and Changes in Cropping Patterns at Kathmandu Valley

Nepal Journal of Science and Technology ◽

10.3126/njst.v7i0.581 ◽

2007 ◽

Vol 7 ◽

pp. 113 ◽

Cited By ~ 1

Author(s):

Raj Man Shrestha

Keyword(s):

Urban Areas ◽

Cropping System ◽

Considerable Change ◽

Rapid Expansion ◽

Leafy Vegetables ◽

Kathmandu Valley ◽

Rapid Urbanization ◽

Average Growth ◽

Cropping Patterns ◽

Agriculture Land

The increase of population in Kathmandu valley is bringing a considerable change in cropping system. Rapid urbanization and introduction of new agriculture technology have encouraged the valley’s farmers to change their cropping patterns from traditional (low value crops) to new crops (high value crops). According to numerous studies made in Nepal, the change is seen considerably in winter crops than in summer crops and the land under cultivation of green leafy vegetables is increasing rapidly in the urban and semi-urban areas. An average growth of population at 3 % in the valley during the period 1951-2001 has resulted in the rapid expansion of area under urban coverage (24.6 % growth per year from 1984 - 2000) has made agriculture land of Katmandu valley to decline per year by 2.04 % (836.27 ha per year). If this trend of decline in agriculture land in Kathmandu valley continues in future too, it is expected that there will be no agriculture land left over by two and half decades in the valley. The planners should take note of this fact that if fertile land of Katmandu valley is to be preserved for agriculture necessary planning is urgently needed. <i>Nepal Journal of Science and Technology</i> Vol. 7, 2006

Download Full-text

Considerations on Ambient Levels of Ozone Concentrations and Relationship with NOx in an Urban Environment

Revista de Chimie ◽

10.37358/rc.17.4.5560 ◽

2017 ◽

Vol 68 (4) ◽

pp. 824-829

Author(s):

Cornel Ianache ◽

Laurentiu Predescu ◽

Mirela Predescu ◽

Dumitru Dumitru

Keyword(s):

Nitrogen Oxides ◽

Urban Areas ◽

Road Traffic ◽

Temporal Distribution ◽

Ground Level ◽

Distinct Pattern ◽

Weekend Effect ◽

Monitoring Site ◽

Ground Level Ozone ◽

Ozone Concentrations

The serious air pollution problem has determined public concerns, worldwide. One of the main challenges for countries all over the world is caused by the elevated levels of ground-level ozone (O3) concentrations and its anthropogenic precursors. Ploiesti city, as one of the major urban area of Romania, is facing the same situation. This research aims to investigate spatial and temporal distribution characteristics of O3 in relationship with nitrogen oxides (NOx) using statistical analysis methods. Hourly O3 and NOx measurements were collected during 2014 year in Ploiesti. The results obtained showed that the ozone spatial distribution was non-normal for each month in 2014. The diurnal cycle of ground-level ozone concentrations showed a mid-day peak, while NOx diurnal variations presented 2 daily peaks, one in the morning (7:00 a.m.) and one in the afternoon (between 5:00 and 7:00 p.m.). In addition, it was observed a distinct pattern of weekly variations for O3 and NOx. Like in many other urban areas, the results indicated the presence of the �ozone weekend effect� in Ploiesti during the 2014 year, ozone concentrations being slightly higher on weekends compared to weekdays. For the same monitoring site, the nitrogen oxides were less prevalent on Saturdays and Sundays, probably due to reducing of road traffic and other pollution-generating activities on weekends than during the week.

Download Full-text

Development of a Line Source Dispersion Model for Gaseous Pollutants by Incorporating Wind Shear near the Ground under Stable Atmospheric Conditions

Environmental Sciences Proceedings ◽

10.3390/ecas2020-08154 ◽

2020 ◽

Vol 4 (1) ◽

pp. 17

Author(s):

Saisantosh Vamshi Harsha Madiraju ◽

Ashok Kumar

Keyword(s):

Air Pollution ◽

Urban Areas ◽

Wind Shear ◽

Dispersion Model ◽

Near Field ◽

Ground Level ◽

Gaseous Pollutants ◽

Air Pollution Control ◽

Mobile Sources ◽

Input Variables

Transportation sources are a major contributor to air pollution in urban areas. The role of air quality modeling is vital in the formulation of air pollution control and management strategies. Many models have appeared in the literature to estimate near-field ground level concentrations from mobile sources moving on a highway. However, current models do not account explicitly for the effect of wind shear (magnitude) near the ground while computing the ground level concentrations near highways from mobile sources. This study presents an analytical model based on the solution of the convective-diffusion equation by incorporating the wind shear near the ground for gaseous pollutants. The model input includes emission rate, wind speed, wind direction, turbulence, and terrain features. The dispersion coefficients are based on the near field parameterization. The sensitivity of the model to compute ground level concentrations for different inputs is presented for three different downwind distances. In general, the model shows Type III sensitivity (i.e., the errors in the input will show a corresponding change in the computed ground level concentrations) for most of the input variables. However, the model equations should be re-examined for three input variables (wind velocity at the reference height and two variables related to the vertical spread of the plume) to make sure that that the model is valid for computing ground level concentrations.

Download Full-text