Large Chinese Cities Research Articles

Contraception and abortion among migrant women in Changzhou, China

Objectives Migrant women in China’s industrial cities face particular contraceptive challenges, which have changed in recent years as family planning policy has shifted. Little is known about recent trends in contraception and abortion among China’s large internal migrant population. We conducted a survey to examine these issues among factory workers in a large Chinese city. Methods Married migrant women (N = 801) aged 20–39 years and working in Changzhou, China, completed an anonymous self-administered questionnaire giving details about their sociodemographic background, work and migration situations, and reproductive health. Results Current contraceptive use was reported by 86.6% of women. Condoms, which have largely replaced longer acting contraceptive methods in this population in recent years, were being used by 54.9% of contraceptive users. Only 41.2% used a longer acting method, mostly an intrauterine device (IUD). A lifetime history of abortion was reported by 40.4%. In the past year, 5.5% had had an unintended pregnancy and 5.2% had had an induced abortion. Older age, lower level of education, lower income, area of origin and husband’s residency were associated with IUD use. Lower income, husband’s residency and stronger fertility desire were associated with recent unintended pregnancy. Conclusion The results of the study provide evidence that migrant women in China are relying more than ever on less effective methods of contraception. Unintended pregnancy and abortion are common. China’s current informed choice model needs to be improved with the provision of better health education before and after migration and easy access to health and reproductive health care services.

China’s Equine Industries in a Transitional Economy: Development, Trends, Challenges, and Opportunities

China had the most horses in the world from 1961 to 2004 but, since the market-oriented economic transition started in the late 1970s, its horse population has declined significantly and steadily, from 11.50 million in 1978 to only 3.47 million in 2018. While there are minimal studies on China’s equine industries in the literature, this paper reviews the development of China’s equine industries since 1949, identifies major factors contributing to the steady decline in its horse population since 1978, and discusses the challenges and opportunities for the development of China’s equine industries. Empirical results suggest that the changes in China’s horse population since 1949 have been closely associated with its agricultural and rural development and policies, and the key factors contributing to the declining horse population since 1978 include agricultural mechanization, a steady decrease of the agricultural sector’s share in the GDP, urbanization, improvement in rural transportation with more motor vehicles, and decreased land availability for and the lack of economic returns from horses. Together, such factors may continue to reduce China’s horse population, but, on the other hand, the rapid development in the tourism, recreation, and sport sectors may provide potential growth opportunities. Moreover, China’s horse population is likely to be more concentrated in Inner Mongolia, Xinjiang, Tibet, and the western Sichuan province, which have relatively low population density and high proportion of ethnic population with the tradition of horses in their cultural, religious, sport, and economic activities. At the same time, equestrian events and activities are expected to continue to increase at significant rates in and around large Chinese cities.

Respecting silence: Longing, rhythm, and Chinese temples in an age of bulldozers

ABSTRACT This essay distinguishes the silence that makes rhythm (and thus ritual) possible, and the silence of loss and longing. It argues that both, as they intertwine, are crucial parts of the adjustment to traumatic change. The interaction between these two kinds of silence offers an alternative to theories that focus primarily on speaking as a way of overcoming trauma, or on silence as antisocial. The ethnographic evidence comes from a surgical case that illustrates the basic approach, followed by a case of rapid urbanization on the outskirts of a large Chinese city, involving the resettlement of 100,000 people. Both cases show the two kinds of silence as they resonate with each other. The analysis argues that silence is not just the absence of sound, but a necessary part of all the rhythms of life, not replaced but invoked by speech.

Effects of indoor activities and outdoor penetration on PM2.5 and associated organic/elemental carbon at residential homes in four Chinese cities during winter

There is increasing public attention on exposure to PM2.5 and its related health impacts. It is essential to study the pollution levels, sources, and health implications of indoor PM2.5, especially for residential homes, as people tend to spend most of their time indoors. The indoor PM2.5 mass and organic/elemental carbon (OC/EC) during winter and early spring period of 2016–2017 at 68 residential households in four large Chinese cities (i.e. Hong Kong, Guangzhou, Shanghai, and Xi'an) were studied. Average indoor PM2.5 varied by two-fold, lowest in Hong Kong (34.0 ± 14.6 μg m−3) and highest in Xi'an (78.7 ± 49.3 μg m−3), with comparable levels for Guangzhou (47.2 ± 5.4 μg m−3) and Shanghai (50.3 ± 17.9 μg m−3). Lowest air exchange rate (AER, 0.8 ± 0.8 h−1) and PM2.5 indoor/outdoor (I/O) ratio (0.72 ± 0.23) were found for Xi'an households, indicating the limited influence from indoor sources, while importance of indoor PM2.5 sources is signified with the highest PM2.5 I/O ratio (1.32 ± 0.43) identified for Shanghai households. For households in four cities, OC and EC accounted for 29.5%–38.5% and 7.5%–8.9% of the indoor PM2.5 mass, indicating the significance of carbonaceous aerosols. Larger differences between indoor and outdoor OC (2.6–8.4%) than EC (−2.2–1.5%) indicate the presence of indoor OC sources. Decreasing trends of PM2.5 I/O ratio and indoor OC proportion were found as the worsening ambient air quality. On average, 11.8 μg m−3 (23.1%) and 3.02 μg m−3 (18.7%) higher indoor PM2.5 and OC concentrations were identified for households with other indoor combustions (e.g., tobacco smoking, incense burning) compared to those with only cooking activities. For Hong Kong and Shanghai households, increments of 13.2 μg m−3 (54.1%) of PM2.5 and 4.1 μg m−3 (45.4%) of OC were found at households with cooking activities as compared to households with no specific indoor combustion.

A thermal comfort field study on subway passengers during air-conditioning season in Beijing

With the massive increase of subway passengers in large Chinese cities, thermal comfort in the subway has become an important topic. The thermal comfort of subway passengers is different from that in above-ground buildings and has its own particularities, as the subway comprises of underground semi-closed buildings. Moreover, the thermal environment experienced by passengers is dynamic. Considering these reasons, this study adopts a dynamic thermal comfort study method for investigating thermal sensations in the subway. The field study was conducted in two Beijing subway stations in May 2016 and June–July 2017, and a total of 628 samples were obtained. Variations in thermal sensation and thermal comfort were analyzed. The results showed that the thermal sensations of subway passengers change dramatically through the entire process, and alternate between hot and cold. For the station hall and platform, although the temperature and the relative humidity were beyond the standard range of the "Code for Design of Metro in China" (GB50157- 2013), passengers find them acceptable. The study also provides reliable basic data for the design and operation management of ventilation and air-conditioning systems in the subway station, so as to create a comfortable thermal environment for subway passengers.

Ambient fine particulate matter pollution and years of life lost from cardiovascular diseases in 48 large Chinese cities: Association, effect modification, and additional life gain

Existing evidence on the associations between fine particulate matter (PM2.5) and years of life lost (YLL) from cardiovascular diseases (CVD) is limited and inconclusive, and the role of potential modifiers, especially those at city-level, is not fully understood. In this study, a time-series study was conducted in 48 large Chinese cities from 2013 to 2017. Generalized additive model coupled with random effects model were used to estimate national-average associations of PM2.5 with YLL. Effect modification by individual- and city-level characteristics obtained by linking with China Chronic Disease and Risk Factors Surveillance was explored. Moreover, additional life gain was evaluated under scenario where PM2.5 concentration would be reduced. For 10 μg/m3 increase in PM2.5 concentration at lag01 day, the relative increment of YLL was 0.22% from CVD, 0.20% from ischemic heart disease, 0.26% from stroke, 0.23% from hemorrhagic stroke, and 0.31% from ischemic stroke. Some associations were stronger in elder and less educated people, warm season, as well as cities characterized by higher temperature and prevalence of binge drinking and excess red meat intake, or lower PM2.5 and prevalence of usual exercise. Additional life gain attributable to avoidable YLL from CVD was estimated to be 0.08 year if PM2.5 concentration could fall to the standard recommended by World Health Organization (25 μg/m3). This large epidemiological investigation demonstrated robust evidence of short-term associations between PM2.5 exposure and YLL from CVD. Potential modifiers should be considered to develop efficient intervention strategies. Implementation of more stringent standard is beneficial to alleviate YLL caused by PM2.5.

Ambient ozone pollution and years of life lost: Association, effect modification, and additional life gain from a nationwide analysis in China

BackgroundOzone is one of the dominant air pollutants due to its impact on disease burden and increasing trend in concentration. However, evidence regarding short-term effect of ozone on years of life lost (YLL) is scarce. MethodsA national time-series study was conducted in 48 large Chinese cities from 2013 to 2017. Generalized additive model coupled with random effects model were used to estimate national-average associations of ozone with YLL. Potential modifiers and additional life gain due to avoidable YLL under certain scenario were also evaluated. ResultsThe average annual mean ozone concentration of these cities was 86.9 μg/m3. For 10 μg/m3 increase in 3-day moving average ozone concentration, we estimated 0.37% [95% confidence interval (CI): 0.29%, 0.46%] increase in YLL from nonaccidental causes, 0.38% (95% CI: 0.30%, 0.46%) increase in YLL from cardiovascular diseases, and 0.36% (95% CI: 0.16%, 0.56%) increase in YLL from respiratory diseases. Moreover, the associations were more evident in people with less education and in cities with lower carbon monoxide concentration or those located at north region with lower mean temperature. Finally, an estimated life of 0.055 (95% CI: 0.043, 0.068) years would be gained per deceased people if ozone concentration could fall to 100 μg/m3. ConclusionsOur findings indicated robust associations between short-term exposure to ozone and YLL from nonaccidental causes and cardiopulmonary diseases. Relevant intervention design should take the heterogeneity of both individual- and city-level characteristics into account. Implementation of more stringent standard is beneficial for alleviating YLL caused by ozone.

Homoprejudiced violence among Chinese men who have sex with men: a cross-sectional analysis in Guangzhou, China

BackgroundHomoprejudiced violence, defined as physical, verbal, psychological and cyber aggression against others because of their actual or perceived sexual orientation, is an important public health issue. Most homoprejudiced violence research has been conducted in high-income countries. This study examined homoprejudiced violence among men who have sex with men (MSM) in Guangzhou, China.MethodsMSM in a large Chinese city, Guangzhou, completed an online survey. Data about experiencing and initiating homoprejudiced violence was collected. Multivariable logistic regression analyses, controlling for age, residence, occupation, heterosexual marriage, education and income, were carried out to explore associated factors.ResultsA total of 777 responses were analyzed and most (64.9%) men were under the age of 30. Three-hundred-ninety-nine (51.4%) men experienced homoprejudiced violence and 205 (25.9%) men perpetrated homoprejudiced violence against others. Men who identified as heterosexual were less (AOR = 0.6, 95% CI: 0.4–0.9) likely to experience homoprejudiced violence compared to men who identified as gay. Men who experienced homoprejudiced violence were more likely to initiate homoprejudiced violence (AOR = 2.44, 95% CI: 1.6–3.5). Men who disclosed their sexual orientation to other people were more likely to experience homoprejudiced violence (AOR = 1.8, 95% CI:1.3–2.5).ConclusionsThese findings suggest the importance of further research and the implementation of interventions focused on preventing and mitigating the effects of homoprejudiced violence among MSM in China.

Polycentric Urban Development and its Determinants in China: A Geospatial Big Data Perspective

The urban structure of large Chinese cities has been well researched, but a systematic analysis of polycentric urban development and the determinants of subcenter formation across municipal districts in cities at the prefectural level and above (PLACMD) is lacking. Using geospatial big data and spatial analysis methods, we measure the urban spatial structure of all 294 PLACMDs to determine the polycentric urban structure in China and conduct an exploratory regression analysis of 59 PLACMDs (due to data restrictions) to explore the formation of polycentric cities. Our results suggest that using location‐based data allows for a timelier and more accurate center identification of detailed urban structural features than using other data. Each PLACMD in China has at least one center, and polycentricity is currently the most common urban spatial structure. PLACMDs with higher populations are more polycentric. Compared with the results obtained from large American urban areas, our regression results imply that population alone accounts for most of the variation in the polycentric index and that commuting costs provide a weak explanation of the existence of Chinese PLACMDs. Both economic development and agglomeration economics are associated with the polycentric index. In contrast, the topographical features are statistically nonsignificant in the regression model.

A computer-based Pinyin intervention for disadvantaged children in China: Effects on Pinyin skills, phonological awareness, and character reading.

Pinyin is an alphabetic script that denotes pronunciations of Chinese characters. Studies have shown that Pinyin instruction enhances both phonological awareness (e.g., Shu et al., Developmental Science, 2008, 11, 171-181) and character reading (e.g., Lin et al., Psychological Science, 2010, 21, 1117-1122) in Chinese children. In the present study, we provided a 3-week Pinyin intervention with a computer-based Pinyin GraphoGame to disadvantaged migrant children with poor Pinyin skills. A total of 252 first graders who were children of migrant workers in a large Chinese city were assessed to identify poor Pinyin readers. Fifty-six 7-year-old children with poor Pinyin skills were selected and randomly divided into a training group and a control group, with 28 children in each group. The training group played the Pinyin GraphoGame for 3 weeks, while the control group received school instruction only during the same period. Results showed that the children in the training group outperformed their peers in the control group on Pinyin reading accuracy and fluency, onset-rime and phonemic awareness, and character reading. These results suggest that the Pinyin GraphoGame may be a cost-effective method to enhance Pinyin and literacy outcomes for underprivileged children in China.

Association of Ambient Air Pollution with Nasopharyngeal Carcinoma Incidence in Ten Large Chinese Cities, 2006-2013.

Large cities in China are experiencing severe ambient air pollution. Although China accounts for more than 45% of new cases of nasopharyngeal carcinoma worldwide in 2018, few studies have examined the association between ambient air pollution and the high nasopharyngeal carcinoma (NPC) incidence in China. Thus, we aim to investigate whether exposure to ambient air pollution (including nitrogen dioxide, sulfur dioxide, and PM10) would significantly affect NPC incidence in large Chinese cities. We collected panel data of ten Chinese provincial cities about local NPC incidence, air pollution level, meteorology, and city profiles during 2006 to 2013 to construct a two-way fixed-effects model to explore the association between ambient air pollution and NPC incidence, as well as possible regional and gender differences behind the association. We found that NO2 had the strongest association with NPC incidence, and the relative risks were 2.2995 (95% CI, 1.2567–4.2075) for males and 1.3010 (95% CI, 0.8212–2.0620) for females, respectively. Under cumulative exposure, it was still NO2 that had the strongest association with NPC incidence, with a relative risk of 1.8836 (95% CI, 1.2416–2.8577), compared to 1.0857 (95% CI, 0.9474–1.2450) and 1.0547 (95% CI, 0.8790–1.2663) for SO2 and PM10, respectively. In addition, males were found more sensitive to ambient air pollution than females. We also found that southern Chinese cities were more sensitive to NO2 than northern cities, which might be related to a higher humidity there. Our study reveals that exposure to ambient air pollutants like SO2, PM10, and particularly NO2, is significantly positively associated with NPC incidence in China.

Potential for global spread of a novel coronavirus from China.

An epidemic of a novel coronavirus emerged from Wuhan, China, in late December 2019 and has since spread to several large Chinese cities. Should a scenario arise where this coronavirus spreads more broadly across China, we evaluate how patterns of international disease transmission could change.

Balancing the strength of external and internal ties for tacit knowledge management

ABSTRACT From external and internal perspective, this research constructs the model regarding tie strength and tacit knowledge management based on social network theory. To test the proposed model, this study disposes and analyses the data captured from 301 emerging firms located in Chinese large cities. The results confirm the proposition that both external and internal tie strength impose a positive effect on the process of tacit knowledge management. In addition, temperate internal tie strength positively affects the relationship between external tie strength and tacit knowledge acquisition, while excessive internal tie strength negatively moderates this relationship. This study not only expands the theoretical space in the field of social networks and knowledge management, but also provides guidance for the enterprise’s relationship network management and innovation practice.

"Quick Response" Economic Stimulus: The Effect of Small-Value Digital Coupons on Spending

We study a new consumption stimulus model that leverages mobile payment platforms to dispense massive amounts of small-value, use-it-this-week-or-lose-it digital coupons. We evaluate the effects of one such program in a large Chinese city using novel data of mobile platform transactions of 1 million program participants. Exploiting participants’ rush to the first-come, first-served digital portal, we compare spending among those who won coupons to those who lost because of minor differences in the timing of their arrival at the portal. We find that coupons generate an immediate increase in weekly consumption among winners by $3 additional out-of-pocket spending for every $1 in government subsidy. Analysis of business customer flows suggests that coupons distort consumption toward more expensive options, leading the program to disproportionately favor big firms that sell pricier goods and services. Relaxing coupons’ minimum spending requirements would alleviate such distributional concern without sacrificing consumer welfare. We conclude that the coupon model can be a useful addition to policy makers’ stimulus toolbox.

The Welfare Implications of Internal Migration Restrictions: Evidence from China

In a system of cities model that incorporates urban externalities, a classical prediction is that equilibrium city sizes deviate from optimal city sizes. Therefore, internal migration restrictions imposed by a country's largest cities could either improve or worsen social welfare. Using a dynamic spatial equilibrium framework and a rich data set of Chinese cities, this paper empirically estimates: (1) whether Chinese cities are too large or too small, both from the local and the national perspective; and (2) how the hukou system impacts the local and national welfare. We find that the largest Chinese cities are too small from the national perspective. China's hukou restrictions have led to a welfare loss of about 6.8% over the 2000-2020 period. While the hukou restrictions enable the largest cities to control their populations in their local interest, the observed city sizes are still greater than their locally optimal levels. Therefore, our results imply a fundamental conflict between local and national interests. Toward the end of this paper, we discuss several policies that might partially resolve this conflict.

Is there a demand for reverse mortgages in China? Evidence from two online surveys

Reverse mortgages provide an alternative source of retirement funding by allowing older homeowners to borrow against their home. However, a recent pilot program of reserve mortgage products in several large Chinese cities saw almost no take up. To ascertain the demand for reverse mortgages in China, we conduct and analyze two online surveys that focus respectively on homeowners aged 45–65 as potential purchasers, and on adult children in the 20–49 age group representing children of potential purchasers. We address the reported shortcomings of the pilot reverse mortgage product by testing an improved product design presented in a clear and comprehensive format. We find that 89% of older Chinese homeowners would be interested in this new reverse mortgage product, and 84% of adult children would recommend such a product to their parents. Participants in both surveys reported that they would use the reverse mortgage payments to fund a more comfortable retirement and to pay for better medical treatments and aged care services. Respondents’ interest in reverse mortgages was associated with their familiarity and understanding of the product, and its perceived potential to address liquidity constraints in retirement. Health status, aged care preferences and proxies for intergenerational links were also important. Our results are contrary to the common perception of intergenerational expectations of wealth transfer in China, and provide new evidence in support of the potential development of China’s reverse mortgage market.

Balanced maximal covering location problem and its application in bike-sharing

With the rapid growth of large-scale cities and the reinforcement of environmental concepts and sustainability, the sharing economy has received increasing attention. The maximum coverage location problem (MCLP), which is the basis of many sharing economy models, aims to cover more customers with a specified number of centers and radii. Many scholars have studied the MCLP Model from various angles and have achieved workload balance under maximum coverage by setting the upper limit of each center's workload. However, there has been little research involving the lower limit of the center. We propose a new MCLP model that includes a lower bound that would improve the quality of results. We also introduce the concept of “balance” that will reduce the imbalance of service levels at various locations. We call the proposed model balanced maximum coverage location problem (BMCLP). We test our model on the bike-sharing problem in a large Chinese city. Our results show the twin accomplishments of better maximal covering results and balanced service. We also show that our model is general enough to be applied to many sharing economy problems.In fact, for shared economic models, guaranteed services and balanced services are crucial for companies. Therefore, according to the basic theory of multiobjective optimization, a balanced maximal covering location problem (BMCLP) is proposed to determine a better design for maximal covering and balanced workload. Using the BMCLP Model successfully in a bike-sharing problem demonstrates that it is more general than the MCLP with demonstrated bounds.

Crime Geographical Displacement: Testing Its Potential Contribution to Crime Prediction

Crime geographical displacement has been examined in many Western countries. However, little is known about its existence, distribution, and potential predictive ability in large cities in China. Compared to the existing research, this study contributes to the current research in three ways. (1) It provides confirmation that crime geographical displacement exists in relation to burglaries that occur in a large Chinese city. (2) A crime geographical displacement detector is proposed, where significant displacements are statistically detected and geographically displayed. Interestingly, most of the displacements are not very far from one another. These findings confirm the inferences in the existing literature. (3) Based on the quantitative results detected by the crime geographical displacement detector, a crime prediction method involving crime geographical displacement patterns could improve the accuracy of the empirical crime prediction method by 7.25% and 3.1 in the capture rate and prediction accuracy index (PAI), respectively. Our current study verifies the feasibility of crime displacement for crime prediction. The feasibility of the crime geographical displacement detector and results should be verified in additional areas.

The linkage between the perception of neighbourhood and physical activity in Guangzhou, China: using street view imagery with deep learning techniques

BackgroundNeighbourhood environment characteristics have been found to be associated with residents’ willingness to conduct physical activity (PA). Traditional methods to assess perceived neighbourhood environment characteristics are often subjective, costly, and time-consuming, and can be applied only on a small scale. Recent developments in deep learning algorithms and the recent availability of street view images enable researchers to assess multiple aspects of neighbourhood environment perceptions more efficiently on a large scale. This study aims to examine the relationship between each of six neighbourhood environment perceptual indicators—namely, wealthy, safe, lively, depressing, boring and beautiful—and residents’ time spent on PA in Guangzhou, China.MethodsA human–machine adversarial scoring system was developed to predict perceptions of neighbourhood environments based on Tencent Street View imagery and deep learning techniques. Image segmentation was conducted using a fully convolutional neural network (FCN-8s) and annotated ADE20k data. A human–machine adversarial scoring system was constructed based on a random forest model and image ratings by 30 volunteers. Multilevel linear regressions were used to examine the association between each of the six indicators and time spent on PA among 808 residents living in 35 neighbourhoods.ResultsTotal PA time was positively associated with the scores for “safe” [Coef. = 1.495, SE = 0.558], “lively” [1.635, 0.789] and “beautiful” [1.009, 0.404]. It was negatively associated with the scores for “depressing” [− 1.232, 0.588] and “boring” [− 1.227, 0.603]. No significant linkage was found between total PA time and the “wealthy” score. PA was further categorised into three intensity levels. More neighbourhood perceptual indicators were associated with higher intensity PA. The scores for “safe” and “depressing” were significantly related to all three intensity levels of PA.ConclusionsPeople living in perceived safe, lively and beautiful neighbourhoods were more likely to engage in PA, and people living in perceived boring and depressing neighbourhoods were less likely to engage in PA. Additionally, the relationship between neighbourhood perception and PA varies across different PA intensity levels. A combination of Tencent Street View imagery and deep learning techniques provides an accurate tool to automatically assess neighbourhood environment exposure for Chinese large cities.

Understanding the spatial distribution of crime in hot crime areas

Hot crime areas are always targeted for police patrol to deter crimes. While much research has studied the distribution patterns of hot crime areas, research on the spatial distribution of crime within hot crime areas remains limited. Using burglary records in a large Chinese city, the ‘hottest’ place with the highest crime density was located using two spatial temporal kernel density estimation methods. The results indicated that the majority of crime within hot crime areas was concentrated within a small area distant from the hot area's center. These results provide a micro view of crime distribution within hot crime areas. Our analysis indicates that the results will not be affected by the methods adopted in identification of hot areas. This research is expected to improve the efficiency of police patrols.