City Size Research Articles

Climate change and city size: the role of temperature difference in the spatial distribution of China's population.

This paper examines the relationship between climate change and the spatial distribution of population in China. We establish a two-way fixed effects model to investigate the role of temperature difference in the spatial distribution of China's population. We find that the annual variation of temperature has an impact on city size in both large and small cities, and that city size tends to shrink as the temperature difference increases. Meanwhile, we also find that the population in the cities located south of Qinling-Huaihe Line and Aihui-Tengchong Line (Hu's Line) is more sensitive to temperature effects, and that the temperature difference has a significant negative effect on city size. Similarly, the same results are found for prefecture-level cities with low administrative levels. Considering the endogeneity between temperature change and city size, we adopt an instrumental variable using latitude to perform a more robust empirical analysis, the results of a series of robustness tests support these conclusions.

Connecting people and places: Analysis of perceived pedestrian accessibility to railway stations by Bavarian case studies

Walking connects different modes of transport and acts as the main feeder for public transport. Nonetheless, ensuring high-quality accessibility for pedestrians to railway stations is seldom evaluated beyond measurable factors such as walking distance and time. Although several studies found differences in calculated and perceived accessibility, little research has so far focused on the factors that are influencing perceived pedestrian accessibility and thus causing these differences. In order to contribute to the current efforts of conceptualizing perceived accessibility, this study explores the factors which determine whether or not people walk to train stations. Potential influencing factors were first derived from a literature review and clustered into six quality criteria (directness, simplicity, traffic safety, security, comfort and built environment). Then, on-site and online surveys were conducted in five Bavarian towns (Germany) to understand the importance of the identified factors and how this differs between different people and places. The results confirm that above all comfort, safety and security factors play an important role for pedestrian accessibility. In addition, significant differences were found between different age groups and city sizes.

Technological innovation, resource endowment, and green total factor energy efficiency.

Technological advancements and resources availability are the main components of green total factor energy efficiency (GTFEE). This study measured GTFEE using the Meta-frontier and Non-radial Directional Distance Function (MNDDF) models and empirically evaluated the effect of technological innovation and resource endowment on GTFEE using dynamic panel and panel threshold models. The following are the primary findings: (1) Throughout the study sample period, the average change trend of China's GTFEE was generally in the shape of a "W," with regional variations. (2) Independent innovation can significantly improve GTFEE, whereas technology introduction has little effect on GTFEE advancement. Similarly, it confirmed the existence of the "Resource Curse." (3) While independent innovation has reduced the severity of the resource curse to a certain extent, the introduction of this technology has no positive effect on the resource curse problem. (4) Heterogeneity research indicates that only large cities' independent innovation has significantly increased GTFEE. There is a particular resource curse phenomenon regardless of the city size, but it is more prominent in small and medium-sized cities. (5) At various phases of economic development, a significant difference was noticed in the impact of independent innovation, technology introduction, and resource endowment on GTFEE.

Use of Smartphone Health Apps Among Patients Aged 18 to 69 Years in Primary Care: Population-Based Cross-sectional Survey.

BackgroundThe World Health Organization has defined mobile health (mHealth) as the “use of mobile and wireless technologies to support the achievement of health objectives.” Smartphones currently represent one of the main media forms for mHealth democratization. Health apps can be an interesting tool for changing health behaviors. However, their use in France is still poorly documented.ObjectiveThe main aim of this study was to evaluate the frequency of use of health apps among patients consulting in the primary care setting in France. The secondary aims were to evaluate the use of health apps according to the sociodemographic and medical characteristics of patients and to determine their use.MethodsA population-based cross-sectional survey was carried out between November 2017 and January 2018 in the Grenoble area of France among patients aged between 18 and 69 years who were consulting at 13 primary care physician offices. Patients were provided with anonymous paper self-questionnaires. The main criterion for participation was the use of a smartphone health app, defined for the purpose of this study as any app supporting patients in efforts to be healthy.ResultsThe participation rate was 49.27% (739/1500; 95% CI 46.7%-51.8%). The smartphone use was estimated at 82.6% (597/723; 95% CI 79.6%-85.2%). Of 597 smartphone owners, 47.7% (283/595; CI 43.6%-51.6%) used at least one smartphone health app. Health apps identified in this study were mainly related to wellness, prevention, and fitness (66.1%), as well as medication, treatments, and follow-up care (50.0%). The main factors associated with health app use were: use of social networks (odds ratio [OR] 3.4, 95% CI 2.1-5.3), age under 30 years (OR 2.7, CI 1.4-4.9), city size between 5001 and 10,000 inhabitants (OR 1.8, CI 1.1-2.8), and city size more than 10,000 inhabitants (OR 2.1, CI 1.4-3.2).ConclusionsIn this survey, nearly one out of two patients reported the use of smartphone health apps, which are currently focused on wellness, prevention, and fitness, and are largely used by the younger population.Trial RegistrationClinicalTrials.gov NCT03351491; https://clinicaltrials.gov/ct2/show/NCT03351491

A model for simulating emergent patterns of cities and roads on real-world landscapes

Emergence of cities and road networks have characterised human activity and movement over millennia. However, this anthropogenic infrastructure does not develop in isolation, but is deeply embedded in the natural landscape, which strongly influences the resultant spatial patterns. Nevertheless, the precise impact that landscape has on the location, size and connectivity of cities is a long-standing, unresolved problem. To address this issue, we incorporate high-resolution topographic maps into a Turing-like pattern forming system, in which local reinforcement rules result in co-evolving centres of population and transport networks. Using Italy as a case study, we show that the model constrained solely by topography results in an emergent spatial pattern that is consistent with Zipf’s Law and comparable to the census data. Thus, we infer the natural landscape may play a dominant role in establishing the baseline macro-scale population pattern, that is then modified by higher-level historical, socio-economic or cultural factors.

Research on Inversion and Correction Method of Urban Light Environment Based on Cooperative Observation

With the continuously growing city size and the increasingly complex and changeable light environment in the city, remote sensing and ground-measured technologies have certain limitations in the research of urban night light environment. The ground-measured data are accurate but low in efficiency and small in scale, while the night-light remote sensing data have the characteristics of high accuracy and large coverage. In this paper, high-resolution night-light remote sensing data and high-accuracy ground-measured data were used to establish an urban ground light environment inversion method with the advantages of remote sensing and ground-measured data in a “space-ground collaboration” approach. A ground database is constructed in GIS based on 26,000 ground measurement data of 4 blocks, 3 spatial perspectives, and 3 light environment parameters. Based on the comparison of the numerical relationship between the measured data of each light environment parameter and each window, the horizontal window is selected as the target window for the ground night light environment inversion research. The urban night light environment inversion method based on the correlation between telemetry and ground- measurement is used to construct and compare the correlation between Luojia night light radiance data and 9 sets of measured data of different ground windows and different light environment parameters. The illuminance measured data of horizontal window and Luojia radiance data, both of which are highly correlated, are selected for regression analysis. The mathematical inversion model of ground illuminance is constructed based on the cubic polynomial model with the lowest RMSE among the six regression models. The inversion result not only has photometric calibration, but also is superior to the original data in terms of population data relevance and accuracy.

The Impacts of Urban Form on PM2.5 Concentrations: A Regional Analysis of Cities in China from 2000 to 2015

The urban form (e.g., city size, shape, scale, density, etc.) can impact the air quality and public health. However, few studies have been conducted to assess the relationship between the urban form and PM2.5 concentrations on a regional scale and long-term basis in China. In this study, we explored the impact of the urban form on the PM2.5 concentrations in four different regions (i.e., northeast, central, east, western) across China for the years 2000, 2005, 2010, and 2015. Five landscape metrics were classified into three characteristics of the urban form (compactness, shape complexity, and urban expansion) using high-resolution remote-sensing data. With considerations given to regional differences, panel-data models and city-level panel data were used to calculate the impact of the urban form on the PM2.5 concentrations. The results of the study indicate that urban expansion is positively correlated with the PM2.5 concentrations across China, with the only exception being the country’s western region, which suggests that urban extension is conducive to increasing the PM2.5 levels in relatively developed regions. Meanwhile, the positive relationship between the irregularity of cities and the PM2.5 concentrations indicates that reducing the urban shape complexity will help to mitigate PM2.5 pollution. Moreover, urban compactness, which mainly refers to the landscape-division-index values, proved to have a negative effect on the PM2.5 concentrations, suggesting that the optimization of urban spatial compactness could reduce PM2.5 levels. The findings of this study are beneficial for a better understanding of the intensity and direction of the effect of the urban form on PM2.5 concentrations.

Water Quality Focusing on the Hellenic World: From Ancient to Modern Times and the Future

Water quality is a fundamental issue for the survival of a city, especially on dry land. In ancient times, water availability determined the location and size of villages and cities. Water supply and treatment methods were developed and perfected along with the evolution of urbanization. In Europe, after the fall of the Roman Empire, water supply and sewage systems went through fundamental changes. However, in medieval times, the lack of proper sanitation and low water quality increased the spreading and effects of epidemics. The importance of potable water quality was established during modern times. In Greece, the significance of water filtration and disinfection was not understood until the beginning of the 20th century. Moreover, the beneficial effects of water quality and sanitation on human health and especially on life expectancy are considered. In Greece and other countries, a dramatic increase in life expectancy mainly after the 2nd World War is probably due to the improvement of potable water quality and hygiene conditions. However, since the mid-20th century, new water quality issues have emerged, such as eutrophication, the improvement of water treatment technologies, as well as chemical and microbiological water pollution problems. This study, in addition to the historical evolution of water quality, highlights and discusses the current issues and challenges with regard to the management and protection of water quality, including global changes in population and urbanization, lack of infrastructure, use of nonconventional water resources, spreading of emerging pollutants and contaminants (e.g., antibiotics and microplastics), and climatic variability impacts. Against these, a review of the main proposed strategies and measures is presented and discussed to protect water quality and maintain water supplies for the future. Understanding the practices and solutions of the past provides a lens with which to view the present and future.

Does City Size Affect International Migrants and Native-Born Workers Differently? Exploring Inequalities in Unemployment and Occupations Across Spanish Cities

The 20th century witnessed populations increasingly concentrated in cities, and this global pattern has persisted into the 21st century. A principal reason for the urban concentration lies in the greater employment advantages offered by bigger metropolises. While this relationship is well documented, few studies have examined whether these benefits differ according to urban dwellers’ birth country. This article analyzes to what extent the migrant–native gap in unemployment and occupational attainment varies according to municipality or city size and, if so, whether that change in inequality is explained by differences in the sociodemographic composition of foreign and native-born populations in big metropolises. Using data from the Spanish General Social Survey, results show that absolute migrant–native labor inequality does vary across city sizes, although in different ways. In larger cities, gross inequality with respect to unemployment seems to be disappearing, whereas in the same places, gross inequality in access to unskilled occupations grows progressively. Controlling for individual, family, and context-related factors explains changes across cities in the unemployment gap, but not in occupational attainment. In other words, big cities do not equalize the risk of unemployment between foreign-born workers and the native-born population but do have a negative impact on equality when it comes to avoiding the occupational ladder's bottom rung. This finding suggests that many international migrants may move to big cities attracted by employment chances, but, in this urban “land of opportunities,” they are more dependent on unskilled jobs and fall into a “trap of precariousness.”

Assortative labor matching, city size, and the education level of workers

We investigate the heterogeneity of assortative labor matching with respect to geography, skills, and tasks. Our contribution is to separate plant quality by education level and occupation tasks using the AKM-model. We introduce a geology-related instrument to analyze the city effect and address limited mobility bias. Using rich administrative worker-plant dataset for Norway, we show that matching of the college educated have a strong city effect. The IV estimates indicate that a doubling of city size increases the correlation between worker and plant quality by 9 percentage points. A wage decomposition shows that matching accounts for 22% of the urban wage premium adjusted for sorting. In terms of occupations, better matching in cities is observed only for non-routine abstract tasks.

How Does City Size Affect the Cost of Household Travel? Evidence from an Urban Household Survey in China.

Travel costs are critical to the sustainable development of cities. This paper used Urban Household Survey (UHS) data from 2002 to 2014 and constructed a comprehensive city-size index from the perspectives of population and urban space to empirically test the impact of city size on the cost of household travel. The main results are as follows: (1) There is a significant positive correlation between city size and the cost of household travel. The internal mechanism is that city size affects the cost of household travel by increasing spatial distance and traffic congestion. (2) Increasing public transportation and per capita road area can restrain the positive impact of city size on the cost of household travel; moreover, the restraining effect of public transportation is stronger than that of per capita road area. (3) The impact of city size on the cost of household travel for sub-provincial cities is smaller than that for ordinary prefecture-level cities; in addition, there is an inverted U-shaped relationship between city size and the cost of household travel. This paper deepens the understanding of the impact of city size on travel costs, providing research support for the healthy development of cities in China.

Geographical location and its impact on the size of cities in Yaqut al-Hamwi

The books of the prolific Arab-islamic geographical heritage represent the products of Arab geographers and travelers through their numerous trips and documented through them the multiple observations that resulted from their visit to many places. Its beginnings are the center of prosperity and growth of human civilization. When travelers moved between cities for commercial or other purposes, they knew the Iraqi cities they visited, as they got to know their locations and geographical nature, as well as their importance in terms of size and its relationship to geographical location, not to mention their of city planning processes. In which the natural geographical foundations had an important role, and as a result of the originality of these geographical observations because they represent the Arab-Islamic civilizational values, it was necessary to stop at one of the most important travelers, Yaqout Al-Hamawi, and focus on his book (Dictionary of Countries), which this research relied on as a basic source, and Yagout lived Al-Hamawi in the seventh century AH and he died in the city of Aleppo in the year 626 AH/1228 AD. Therefore, this research came to study the geographical location and its impact on the size of the cities at Yakut al-Hamawi

Police in the Western Remote Parts of the Empire: the Structure, Functions and Personnel of the Vilna City Police Department at the Beginning of the 20th Century

At the beginning of the 20th century, the Vilna City Police Department had a police density higher than the average in most cities of the same size in the German or British Empires. However, taking into account the multi-ethnicity of the population, the border position of the city and its accelerated socio-economic development, the police staff was not excessively significant. The existing police staff proved to be incapable of resisting alone the mass political riots in 1905. On the initiative of both the government and local authorities, the quality of police control over crime was improved. Most of the police were recruited from the local residents, with Catholics dominating among the lower ranks of the police, despite the attempts of the authorities to change that. The structure of the city police department was similar to that of the central provinces of the empire.

Economic burden of dengue fever in China: A retrospective research study.

BackgroundDengue fever has been a significant public health challenge in China. This will be particularly important in the context of global warming, frequent international travels, and urbanization with increasing city size and population movement. In order to design relevant prevention and control strategies and allocate health resources reasonably, this study evaluated the economic burden of dengue fever in China in 2019.MethodsThe economic burden of dengue fever patients was calculated from both family and the organisation perspectives. A survey was conducted among 1,027 dengue fever patients in Zhejiang, Chongqing, and Yunnan Provinces. Treatment expenses, lost working days, and insurance reimbursement expenses information were collected to estimate the total economic burden of dengue fever patients in 2019. The expenditures related to dengue fever prevention and control from government, Center for Disease Control and Prevention (CDC), communities and subdistrict offices of 30 counties (or districts) in Zhejiang Province and Chongqing City were also collected.ResultsThe direct, indirect and total economic burden for dengue fever patients in 2019 in the three Provinces were about 36,927,380.00 Chinese Yuan (CNY), 10,579,572.00 CNY and 46,805,064.00 CNY, respectively. The costs for prevention and control of dengue fever for the counties (or districts) without cases, counties (or districts) with imported cases, and counties (or districts) with local cases are 205,800.00 CNY, 731,180.00 CNY and 6,934,378.00 CNY, respectively. The total investment of dengue fever prevention and control in the 30 counties in China in 2019 was approximately 3,166,660,240.00 CNY.ConclusionThe economic burden of dengue fever patients is relatively high, and medical insurance coverage should be increased to lighten patients’ direct medical economic burden. At the same time, the results suggests that China should increase funding for primary health service institutions to prevent dengue fever transmission.

Spatiotemporal Patterns and Dominant Factors of Urban Particulate Matter Islands: New Evidence from 240 Cities in China

With rapid urbanization and industrialization, PM2.5 pollution exerts a significant negative impact on the urban eco-environment and on residents’ health. Previous studies have demonstrated that cities in China are characterized by urban particulate matter island (UPI) phenomena, i.e., higher PM2.5 concentrations are observed in urban areas than in rural settings. How, though, nature and socioeconomic environments interact to influence UPI intensities is a question that still awaits a general explanation. To fill this knowledge gap, this study investigates spatiotemporal variations in UPI effects with respect to different climatic settings and city sizes in 240 cities in China from 2000 to 2015 using remotely sensed data and explores the effective mechanism of human–environmental factors on UPI dynamics based upon the Geographically Weighted Regression (GWR) model. In particular, a conceptual framework that considers natural environments, technology, population, and economics is proposed to explore the factors influencing UPIs. The results show (1) that about 70% of the cities in China selected exhibited UPI effects from 2000 to 2015. In addition, UPI intensities and the number of UPI-related cities decreased over time. It is noteworthy that PM2.5 pollution shifted from urban to rural areas. (2) Elevation was the most efficient driving factor of UPI variations, followed by precipitation, population density, NDVI, per capita GDP, and PM2.5 emission per unit GDP. (3) Climatic backgrounds and city sizes influenced the compositions and performance of dominant factors regarding UPI phenomena. This study provides valuable a reference for PM2.5 pollution mitigation in cities experiencing global climate change and rapid urbanization and thus can help sustainable urban developments.

Information infrastructure and greenhouse gas emission performance in urban China: A difference-in-differences analysis

Owing to its network spillover effect, information infrastructure performs outstandingly in promoting economic growth and technological innovation, and has received widespread attention. However, the ecological performance of information infrastructure, especially its impact on greenhouse gas (GHG) emission performance, has been less studied. To investigate this issue, using panel data for 281 prefecture-level cities in China from 2003 to 2018, we treat the Broadband China policy as a quasi-natural experiment in information infrastructure, and conduct a difference-in-differences (DID) analysis. The results show that: (1) Information infrastructure significantly improves urban GHG emission performance. This conclusion holds even after controlling for pilot selection endogeneity, sampling bias, and other policy interference. (2) Technological innovation, industrial structure upgrading, factor allocation enhancement, and tertiary agglomeration are effective channels for information infrastructure to improve GHG emission performance. (3) The treatment effect varies with city size, digital economy level, and economic status. Specifically, information infrastructure exhibits significant emission reduction performance in cities with large size, advanced digital economy, and leading economic status, while the emission reduction effect drops in other cities. This study provides insights into the transition to a carbon-neutral manner for infrastructure in China and other developing countries.

Language statistics as a window into mental representations

Large-scale linguistic data is nowadays available in abundance. Using this source of data, previous research has identified redundancies between the statistical structure of natural language and properties of the (physical) world we live in. For example, it has been shown that we can gauge city sizes by analyzing their respective word frequencies in corpora. However, since natural language is always produced by human speakers, we point out that such redundancies can only come about indirectly and should necessarily be restricted cases where human representations largely retain characteristics of the physical world. To demonstrate this, we examine the statistical occurrence of words referring to body parts in very different languages, covering nearly 4 billions of native speakers. This is because the convergence between language and physical properties of the stimuli clearly breaks down for the human body (i.e., more relevant and functional body parts are not necessarily larger in size). Our findings indicate that the human body as extracted from language does not retain its actual physical proportions; instead, it resembles the distorted human-like figure known as the sensory homunculus, whose form depicts the amount of cortical area dedicated to sensorimotor functions of each body part (and, thus, their relative functional relevance). This demonstrates that the surface-level statistical structure of language opens a window into how humans represent the world they live in, rather than into the world itself.

Urban population distribution in China: Evidence from internet population

Based on mobile internet user data, we construct an “Internet population” measure and reexamine spatial population distribution in China. The location based service (LBS) data of mobile internet uses is able to capture the accurate location of users' residence and solve the underestimation problem of missing migrants. We have three main findings. First, contrary to previous studies based on traditional population statistics, city size distribution of Internet population fits well into Zipf's law with a R2 of 90.7%. Second, the Internet population indicator is superior to traditional population statistics in explaining inelastic household consumption such as water consumption, electricity consumption, and garbage disposal. It suggests that the “Internet population” is a better proxy of actual city population. Third, the traditional population statistics systematically overestimate population in small cities and underestimate population in large cities. It indicates that the public resource distortions will continue to exist or even worsen off in China if the allocation process relies greatly on traditional population statistics. Although no measures are perfect, our new population measure provides important incremental information for future discussion.

Diversity in global urban sprawl patterns revealed by Zipfian dynamics

ABSTRACT Zipf’s law, characterizing the rank-size distribution of city size or population, has been widely applied in urban studies. Previous studies on Zipf’s law mainly focused on the spatial dimension of urban size and population, with limited consideration of its temporal dynamics. Here, we proposed a conceptual model to characterize the spatial sprawl pattern of urban clusters using the approach of Zipf’s law and approximately 30-year time series of global urban extent data. First, we quantified increments of urban areas in global megacities and small settlements over the past three decades. Urban sprawl patterns (i.e., equilibrium, diffuse, and aggregated) were revealed from the Zipfian dynamics, using the proposed conceptual model. Then, we characterized urban sprawl patterns at different spatial scales. Overall, the sprawl of small urban clusters is slightly faster than those of large clusters globally. At the continental scale, the sprawl pattern shows equilibrium patterns in Asia and Africa, whereas other continents mainly present diffuse sprawl patterns. In general, for developing regions (e.g., North and West Africa), an aggregated sprawl pattern was observed, whereas, for those highly developed regions (e.g., Canada and West Europe), the diffuse sprawl pattern dominated. Patterns of urban sprawl revealed in this study reflect different growth rates of varying sizes of urban clusters, advancing our understanding of urban development pathways. The relatively robust performance of Zipf’s law over multiple spatial and temporal dimensions suggests the self-organized mechanism of city evolution behind urban sprawl, which contributes to the development of future urban growth models.

Urban growth rates, trajectories, and multi-dimensional disparities in China

It is undeniable that the process of urbanization in China is a massive phenomenon of scale and speed in humanity history. The relentless march of urbanization poses a critical challenge for creating a comprehensive analysis of the integrated characteristics of contemporary cities. Here, we integrated 30 m continuous and consistent human settlement areas to quantify spatiotemporal dynamics of urban development in 344 prefectural-level cities of China from 1987 to 2017 via Gibrat's law. Results indicated that China had experienced a rapid urbanization process during the past three decades with annual expansion and annual growth rates of 3877.93 km2 and 5.84%, respectively. A key finding was that city growth rate was inversely proportional to initial city size, therefore contradicting Gibrat's law, whose performance was relevant to shifts in urbanization policies. Furthermore, results also highlighted interregional disparities between the southwest and northwest and other regions, as well as intra-regional differences within geographical, urban sizes, and administrative levels. Exploring the validity of Gibrat's law involving the links between city size and growth rate in China deepens our theoretical insights and, more importantly, will make policymakers aware of the need to adopt a holistic approach by considering the uneven nature of urbanization toward better sustainability.