Does Density Aggravate the COVID-19 Pandemic? Hamidi, Shima; Sabouri, Sadegh; Ewing, Reid
Journal of the American Planning Association,
10/1/2020, 2020-10-01, Volume:
86, Issue:
4
Journal Article
Peer reviewed
Open access
Problem, research strategy, and findings: The impact of density on emerging highly contagious infectious diseases has rarely been studied. In theory, dense areas lead to more face-to-face interaction ...among residents, which makes them potential hotspots for the rapid spread of pandemics. On the other hand, dense areas may have better access to health care facilities and greater implementation of social distancing policies and practices. The current COVID-19 pandemic is a perfect case study to investigate these relationships. Our study uses structural equation modeling to account for both direct and indirect impacts of density on the COVID-19 infection and mortality rates for 913 U.S. metropolitan counties, controlling for key confounding factors. We find metropolitan population to be one of the most significant predictors of infection rates; larger metropolitan areas have higher infection and higher mortality rates. We also find that after controlling for metropolitan population, county density is not significantly related to the infection rate, possibly due to more adherence to social distancing guidelines. However, counties with higher densities have significantly lower virus-related mortality rates than do counties with lower densities, possibly due to superior health care systems.
Takeaway for practice: These findings suggest that connectivity matters more than density in the spread of the COVID-19 pandemic. Large metropolitan areas with a higher number of counties tightly linked together through economic, social, and commuting relationships are the most vulnerable to the pandemic outbreaks. They are more likely to exchange tourists and businesspeople within themselves and with other parts, thus increasing the risk of cross-border infections. Our study concludes with a key recommendation that planners continue to advocate dense development for a host of reasons, including lower death rates due to infectious diseases like COVID-19.
Average population density has been a traditional urban sprawl indicator, but it is insufficient to encapsulate its detrimental impacts. We demonstrate that cities of identical average population ...density may be subject to very different levels of car dependency, CO2 emissions and public budget deficits. To capture this, we shed light into the properties of two “density-allocation” indicators: the percentage of urban land in which population density falls below a predetermined threshold value, and the fraction of the population living in such areas. Using unique data, we measure these indicators in more than 1100 urban areas of 29 OECD countries and at three time points: 1990, 2000 and 2014. We identify four different patterns for the coevolution of average population density and these indicators. The results show that densification of urban cores concurs with rapid suburbanization in many cities. We perform intertemporal cross-city and cross-country analyses and discuss the multiple policy implications emerging from them.
•We examine the properties and socioeconomic importance of density-allocation sprawl indicators.•We measure the density-allocation indicators in more than 1100 cities, 29 OECD countries and in three time points: 1990, 2000, 2014.•We identify four patterns for the ways density-allocation indicators coevolve with average population density.•Reducing sprawl through changes in the density-allocation indicators involves different policies than those being effective in increasing average population density.•Core densification may concur with rapid suburbanization.
Decentralization in Indonesia has led to a shift in responsibilities from the central government to the regions. This has been observed in the distribution of jobs and population across metropolitan ...areas, such as in the Yogyakarta Metropolitan Area (Kartamantul). Kartamantul is a secondary metropolitan area in Indonesia where local governments have taken the initiative to jointly form a Joint Secretariat. The development of Kartamantul has expanded into the peripheral areas, as evidenced by changes in land use. This article examines the impact of decentralization by the Government of the Special Region of Yogyakarta on the phenomenon of urban sprawl in the Kartamantul Region. The analytical method used is descriptive analysis, with secondary data collection from previous research on decentralization and urban sprawl in Yogyakarta. The results of the analysis identify the characteristics of urban sprawl in Kartamantul based on three aspects: land use change, population growth, and economic growth. By 2017, there had been changes in non-built-up land use in the peri-urban areas of Yogyakarta, accompanied by population growth and economic expansion. The Joint Secretariat of Kartamantul has come up with solutions to address the urban sprawl phenomenon, such as the addition of Trans-Jogja routes reaching Bantul and Sleman regencies, as well as collaborative management of the Piyungan Landfill and Sewon WWTP. The conclusion of this research is that cooperation among regional governments through the Joint Secretariat of Kartamantul is an effective grassroots initiative. However, there is a need for the Joint Secretariat to be involved in spatial planning due to the complex development challenges in Kartamantul.
Urban sprawl has become a remarkable characteristic of urban development worldwide in the last decades. Urban sprawl refers to the extent of urbanization, which is a global phenomenon mainly driven ...by population growth and large scale migration. In developing countries like Iran, urban sprawl is taking its toll on the natural resources at an alarming pace. The purpose of this paper is to study urban growth and effective factors on them in the city of Urmia, Iran. We used quantitive data of the study area from the period between 1989 and 2007, and population censuses of Urmia. To measure the model of urban growth, Holderness and Shannon’s entropy were employed. The Urmia case is interesting for several reasons: first, it is a case of very fast urban growth even for a developing country; second, it illustrates how the fastest rates of urban sprawl may correspond to middle size cities rather than to large centers. Third, it portrays a land substitution process in which agricultural land is not the primary provider of urban land which is relatively rare in urban contexts, and fourth, it also illustrates how urban sprawl may also hide important internal land uses such as the presence of agricultural plots within urban boundaries.
The effects of the main transportation arteries on the urban sprawl and the formation of new public spaces is an important topic of discussion today. Considering the urban roads, major arteries ...trigger fast development and the formation of a significant amount of urban open space together with buildings. Vehicular roads are the main elements that bring out urbanity and centrality by providing a combination of circulation at different speeds and making possible the interaction of users from local and remote areas (Jacobs, 1969; Nijenhuis, 1994 and Read, 2006). In this context, sub-spaces were defined as public spaces that are beside / under / above / between / within vehicular roads and the sub-space perceptions of pedestrians in the case of the closest part of Ankara Eskisehir Road to the city center, were investigated in an earlier study (Alanyali Aral and Demirbas, 2015). In the current study, Sogutozu is defined as a developing node with its rapidly increasing built stock and function density on one of the most important transportation arteries of the city, and its urban features are discussed within the scope of the emerging open spaces. Despite the unsuitable conditions, Sogutozu node displays a constant pedestrian density, and with this feature, it exemplifies 'activity' as an important indicator, which Montgomery (1998) defines as one of the three components of the concept of 'urbanity'. Accordingly, a conceptual framework is developed on the characteristics of urbanity, activity and public space, and then the components of the open space stock are discussed within the scope of spaces of 'places' and 'flows' (Nijhuis and Jauslin, 2015) specific to developing nodes. Spaces of 'places' in developing nodes include privately owned public use spaces, in-between spaces and informal public spaces -'fourth place's (Aelbrecht, 2016). The spaces of the 'flows', on the other hand, are discussed as pedestrian spaces that enhance urbanity. In the case study, firstly the historical and current development of Sogutozu node is examined, and then a comprehensive model based on the relevant pedestrian needs is suggested to evaluate the activity-based urbanity in the node. The defining elements of the activity-based urbanity are explored via map analysis and on-site observations, whereas the pedestrian perceptions in the node are investigated with the applied questionnaires. The results show that the pedestrian experience is negatively affected due to the conditional and intermittent pedestrian access, as well as the inability to provide physical, psychological and physiological comfort; nevertheless, many and various activities add vitality to the area which result in many informal public spaces (fourth places) formed at the entrances and transitions to the public and semi public spaces. The questionnaire survey, which was conducted with fewer but still comparable numbers of users due to the pandemic conditions, included the pedestrian perception questions in the survey conducted in 2005-2007. It is seen that although today the perception of traffic such as noise increased slightly, the perception of air pollution and traffic safety problems decreased. Additionally, the perception of public space qualities like well-known and dynamic / lively spaces increased significantly and constituted the most common perception after the perception of noisy / tiresome space. The results reveal that open spaces in the node of Sogutozu, where mixed use, large-scale and fragmented complexes are dominant, cannot provide environmental and internal continuity as well as appropriate walking environment within the framework of activity-based urbanization, and thus necessitate a holistic urban design approach. The urbanism formed in this rapidly developing node can be enhanced by temporal and spatial continuities; in addition to provision of pedestrian comfort with the arrangements to reduce the negative effects of motor vehicle dominance. The overall evaluation validates that the open spaces in the node should be enriched with accessible spaces for all users, carefully designed indoor-outdoor relations, cultural uses, small-scale businesses and activities spanning time. Keywords: Urbanity; activity; public space; pedestrian perception; Ankara Kentlerde ana ulasim arterlerinin kentsel sacaklanmaya ve yeni kamusal mekanlarin olusumuna etkileri gunumuzde onemli bir tartisma konusudur. Kentsel yollar dusunuldugunde ana arterler hizli yapilasma ile birlikte onemli miktarda kentsel acik mekanin da olusumunu tetiklemektedir. Arac yollari, yakin cevre ile uzak alanlardan farkli hizlarda dolasimin biraradaligmi saglayarak kentsellik ve merkez ozelliklerini ortaya cikaran ana unsurlardir (Jacobs, 1969; Nijenhuis, 1994 ve Read, 2006). Bu baglamda kent ici otoyollarda yol boyu yan-mekanlar, otoyollarin yaninda / altinda / ustunde / arasinda kalan ve kamusallik ozelliklerine sahip mekanlar olarak tanimlanmis ve Ankara Eskisehir Yolu orneginde yolun kent merkezine en yakin kismi olarak Dumlupmar Yolu'nun Mevlana Bulvari'na yakin kisminda yayalarin yan-mekan algilari daha once arastirilmistir (Alanyali Aral ve Demirbas, 2015). Bu calismada ise Sogutozu, kentin en onemli ulasim arterlerinden biri uzerinde hizla artmakta olan yapi ve islev yogunluguyla gelismekte olan bir odak olarak tanimlanmakta ve ortaya cikan acik alanlar butunu kapsaminda sergiledigi kentsellik ozellikleri tartisilmaktadir. Sogutozu odagi uygun olmayan kosullara ragmen surekli yaya yogunlugu sergilemekte, bu ozelligi ile Montgomery'nin (1998) 'kentsellik' kavraminin uc bileseninden biri olarak tanimladigi 'aktivite'yi onemli bir gosterge olarak orneklemektedir. Bu cercevede yazin taramasinda oncelikle kentsellik, aktivite ve kamusal mekan ozellikleri uzerinden kavramsal bir cerceve olusturulmus, daha sonra gelismekte olan odaklar ozelinde acik mekan stokunun bilesenleri 'yerlerin' mekanlari ve 'akislarin' mekanlari (Nijhuis ve Jauslin, 2015) basliklari altinda incelenmistir. Gelismekte olan odaklarda 'yerlerin' mekanlari, ozel mulkiyetteki kamusal kullanim mekanlari, ara-mekanlar ve enformei kamusal mekanlar -Dorduncu Yer (Aelbrecht, 2016); 'akislarin' mekanlari ise kentselligi destekleyen yaya mekanlari olarak ele alinarak tartisilmistir. Alan calismasinda Sogutozu odaginin tarihi ve guncel gelisimi incelenmis, odaktaki acik mekanlarin aktivite bazli kentsellik ozelliklerini degerlendirmek icin konuyla iliskili yaya gereksinimlerini temel alan kapsamli bir model olusturulmustur. Odaktaki aktivite bazli kentselligin tanimlayici unsurlari harita analizleri ve yerinde gozlemlerle, odaktaki yaya algilari ise uygulanan anketlerle arastirilmistir. Sonuclar, yaya erisiminin kosullu ve kesintili olmasi yaninda fiziksel, psikolojik ve fizyolojik konforun saglanamamasi nedeniyle yaya deneyimini olumsuz etkilenmekte oldugunu; bununla birlikte cok ve cesitli aktivitelerin alana canlilik kattigini ve yapilarin kamusal / yari-kamusal kullanim alanlarina giris ve gecislerde pek cok sosyallesme mekani olustugunu gostermektedir. Pandemi kosullari nedeniyle daha az ancak yine de karsilastirilabilir sayida kullaniciyla yapilan anket calismasi, 2005-2007 yillarinda yapilan anket calismasindaki yaya algisi sorulariyla olusturulmus; gurultu gibi trafikle ilgili algilarinin biraz artmasina karsin hava kirliligi ve trafik guvenligi sorunlari algisinin azaldigi, buna karsilik kamusal ve dinamik / canli mekan algilarinin belirgin bir sekilde arttigi ve gurultulu / yorucu mekan algisindan sonra en yaygin algiyi olusturdugu gorulmustur. Sonuclar, cok kullanimli, buyuk olcekli ve parcacil yapilasmalarin baskin oldugu Sogutozu odaginda acik alanlarin aktivite temelli kentsellik cercevesinde cevresel ve ic sureklilik yaninda uygun yurume ortamini da saglayamadigini, bu kapsamda butuncul bir kentsel tasarim yaklasimiyla ele alinmasinin geregini ortaya koymaktadir. Hizla gelismeye devam eden bu odakta olusan kentselligin zamansal ve mekansal surekliliklerle desteklenebilecegi; acik mekanlardaki motorlu arac baskinliginin olumsuz etkilerinin azaltilmasina yonelik duzenlemelerle yaya konforunun saglandigi rotalar yaninda tum kullanicilar icin erisilebilir mekanlar, ozenle tasarlanmis ic-dis mekan iliskileri, kulturel kullanimlar, kucuk olcekteki isletmeler ve zamana yayilan aktivitelerle zenginlestirilmesi gerektigi gorulmektedir. Anahtar Sozcukler: Kentsellik; aktivite; kamusal mekan; yaya algisi; Ankara
With the neo-metamorphosis of the residential landscape worldwide and sluggish sanitation strategies in urban environments, rudimentary on-site sanitation systems remain commonly used, especially in ...developing countries, despite the risks of groundwater contamination. The effective management of such water resources relies on assessment of the sensitivity of anthropized aquifers to man-made impact, including groundwater behavioural alteration, in terms of both quality and quantity. Associated with tracking of changes in land use, this study proposes an approach involving emerging organic contaminants (EOCs) as indicators of the alteration of groundwater balance due the exposure of shallow aquifers to the risks of infiltration of untreated wastewater from soak pits. This methodology was applied to the shallow aquifer beneath the urban agglomeration of Grand-Sfax (Tunisia). Combined with an updated follow-up of groundwater piezometric fluctuations in relation with inputs from surface contamination sources, the spatialisation of contamination levels by EOCs provided a clear delineation of the most impacted aquifer zones. This approach revealed a significant link between the continuous rise in piezometric levels by contributions from untreated inputs and the accumulation of high levels of contamination in groundwater. The understanding of EOC underground pathways allowed the determination of the fates and processes responsible for the diffusion of contamination throughout the studied aquifer. The ability of groundwater to reflect population life style and the use patterns of such organic molecules was also assessed. Besides revealing the legacy of persistent contamination, this approach involving EOCs as tracers with different levels of persistence provided a spatial observation of the aquifer exposure to continuous contamination processes. This approach made it possible to develop a conceptual presentation of aquifer vulnerability to urban pressures and to predict the effects of subsequent expansion of unplanned urbanisation on groundwater quality.
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•Assessment of aquifer vulnerability to unplanned urban expansion and poor sanitation•Increasing groundwater level due to untreated wastewater infiltration from soak pits•Clear relationship between the piezometric rise and contaminants accumulation•Highlighting the issues of the legacy of persistent contamination in groundwater•Groundwater contamination reflects the use patterns of EOCs by population
The land of the conterminous United States (CONUS) has been transformed dramatically by humans over the last four centuries through land clearing, agricultural expansion and intensification, and ...urban sprawl. High-resolution geospatial data on long-term historical changes in land use and land cover (LULC) across the CONUS are essential for predictive understanding of natural-human interactions and land-based climate solutions for the United States. A few efforts have reconstructed historical changes in cropland and urban extent in the United States since the mid-19th century. However, the long-term trajectories of multiple LULC types with high spatial and temporal resolutions since the colonial era (early 17th century) in the United States are not available yet. By integrating multi-source data, such as high-resolution remote sensing image-based LULC data, model-based LULC products, and historical census data, we reconstructed the history of land use and land cover for the conterminous United States (HISLAND-US) at an annual timescale and 1 km x 1 km spatial resolution in the past 390 years (1630-2020). The results show widespread expansion of cropland and urban land associated with rapid loss of natural vegetation. Croplands are mainly converted from forest, shrub, and grassland, especially in the Great Plains and North Central regions. Forest planting and regeneration accelerated the forest recovery in the Northeast and Southeast since the 1920s. The geospatial and long-term historical LULC data from this study provide critical information for assessing the LULC impacts on regional climate, hydrology, and biogeochemical cycles as well as achieving sustainable use of land in the nation. The datasets are available at
China's unprecedented urbanization has resulted in accelerating urban sprawl, which is threatening the country's eco-environmental quality and socioeconomic sustainability. In this study, we ...integrated urban land census data and urban district population data to examine the pattern of urban sprawl and identify differences, and to investigate the socioeconomic drivers of urban sprawl in China between 2006 and 2014. The results revealed that China has experienced drastic urban sprawl over almost all of the last decade with an average urban sprawl index (USI) of 3.16%. However, the rate of urban sprawl has decreased since 2010. In addition, regional distribution, urban size, and hierarchy have different effects on urban sprawl. In particular, cities with severe urban sprawl should be noted, such as large and medium cities in eastern China, large cities in central China, small-A and large-B cities in western China, and large-A cities in northeast China. We also found that urban sprawl was significantly associated with urban population density, gross domestic product (GDP) per capita, and industrial structure. Further, when the spatial heterogeneity was considered, the driving forces of urban sprawl exhibited different magnitudes and directions. Our results indicate that to formulate effective urban planning and land use policies, decision-makers should seriously consider the differences in urban sprawl depending on region, urban size, and hierarchy.
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•The spatio-temporal pattern of urban sprawl in China was explored during 2006–2014.•Intensity of urban sprawl has reduced since 2010.•Differences of urban sprawl in regions, urban sizes and administrative levels are significant.•Urban sprawl was related with changes in population, economic growth, and industrial structure.•Drivers of urban sprawl in the regions, urban sizes and hierarchies were notably differential.
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