The climate backgrounds of urban migrants affect thermal response

Su Y., Li Z., Wang C., Meng Q., Gong A., Wu Z., Zhao Q.

Human thermal perception varies with climate. The Dwa climate zone covers vast areas. Conducting outdoor thermal comfort (OTC) studies here would benefit energy efficiency and the economy. However, since OTC research methods are not standardized, different research methods hamper comparing studies in the Dwa climate. This paper aims to determine the summer OTC of typical Dalian squares in the Dwa climate. Dalian is located in the cold A zone (2A) of the China Building Climate Division. The thermal environment of three typical squares was field measured, and a questionnaire survey of the residents was conducted. 33.2 % of Dalian residents evaluated the thermal environment as neutral, and 39.3 % considered it comfortable. And psychological perception and physical perception were not the same. Multiple methods were used to calculate outdoor thermal benchmarks and calibrate thermal stress for three thermal indexes, SET*, PET, and UTCI. Furthermore, PET, with a prediction accuracy of 25.3 %, was determined to be the best indicator applicable to Dalian in the summer. Finally, a comparison of studies under the Dwa climate zone, including Tianjin and Harbin, reconfirmed the mobility of the human thermal zone. These findings are precious and can contribute significantly to ensuring the sustainability of the outdoor environment.

Sun X., Liu H., Liao C., Nong H., Yang P.

Recreational ecosystem service (RES) supply and demand are fundamentally influenced by urbanization and are closely related to residents’ well-being. Nevertheless, how socio-economic attributes affect spatial RES demand and preferences and can be integrated into urban–rural planning is still unclear. Taking the Beijing-Tianjin-Hebei urban agglomeration region of China as an example, based on survey and spatial data, we applied the Recreation Opportunity Spectrum and a new transferable Quasi-Poisson regression model to examine spatial RES supply and demand. Then, a scaling approach was adopted to interpret the urban–rural spatial patterns of RES. The results showed that the RES supply values exhibited either quadratic relationships or no particular patterns in most cities along urban–rural gradients, while the RES demand values monotonically decreased with an exponential decay or power law. The RES imbalance with higher demand (43%) in urban areas, the supply–demand balance (37%) in urban–rural fringes, and the supply sufficiency (64%) in rural areas were dominant. Divergent RES demand and preferences were identified across genders, ages, income, city scales, and household statuses. Females showed higher preferences for water, grassland, and agricultural landscapes than males; older groups showed higher preferences for natural landscapes but traveled less distance for RES; and high-income groups showed a lower frequency of visits but pursued longer travel distances. We suggest that at both the regional-city and local-community levels, more adaptive and elaborate landscape planning and design should be implemented by integrating urban–rural heterogeneity and the specific population’s preferences into RES management.

Yang Y., Wang Z., Zhou F., Hao H., Liu C.

Preference for thermal environments is affected by the thermal histories on their own. A deeper understanding of human thermal adaptation to create comfortable and energy-saving environments is desired. To study the differences in thermal responses of southern migrants and northern locals to district heating environments, a longitudinally traced investigation was performed in the severe cold area, China. 74 freshmen with different thermal histories were invited for six weeks in winter. Physiological parameters and thermal response votes were collected. Results showed that the most significant difference in the thermal neutral temperature between locals and migrants reaches up to 1.1°C, after acclimation, which decreases to 0.7 °C. Also, southern immigrants are not as sensitive to temperature changes as locals, but the gap is narrowing. Moreover, immigrants tended to wear lighter clothing at the same room temperature compared to natives, who were more flexible in adjusting their clothing. It was also observed that physiological and psychological adaptation processes were not synchronous. The humidity is the leading purpose of physiological discomfort for migrants. Physiological adaptation is a relatively slow process. It concluded that southern immigrants may take approximately 1 week to adapt to the thermal environment with district heating. However, they did not fully adapt to the humid environment until the 6th week. The findings have implications for understanding the mechanisms of thermal adaptation and creating comfortable built environments.

U-Din M., de Mello V.D., Tuomainen M., Raiko J., Niemi T., Fromme T., Klåvus A., Gautier N., Haimilahti K., Lehtonen M., Kristiansen K., Newman J.W., Pietiläinen K.H., Pihlajamäki J., Amri E., et. al.

Cold-induced brown adipose tissue (BAT) activation is considered to improve metabolic health. In murine BAT, cold increases the fundamental molecule for mitochondrial function, nicotinamide adenine dinucleotide (NAD+), but limited knowledge of NAD+ metabolism during cold in human BAT metabolism exists. We show that cold increases the serum metabolites of the NAD+ salvage pathway (nicotinamide and 1-methylnicotinamide) in humans. Additionally, individuals with cold-stimulated BAT activation have decreased levels of metabolites from the de novo NAD+ biosynthesis pathway (tryptophan, kynurenine). Serum nicotinamide correlates positively with cold-stimulated BAT activation, whereas tryptophan and kynurenine correlate negatively. Furthermore, the expression of genes involved in NAD+ biosynthesis in BAT is related to markers of metabolic health. Our data indicate that cold increases serum tryptophan conversion to nicotinamide to be further utilized by BAT. We conclude that NAD+ metabolism is activated upon cold in humans and is probably regulated in a coordinated fashion by several tissues.

Wang X., Wang Y., Liu N.

The economic differentiation between the north and the south of China, as a long-standing phenomenon of unbalanced regional economic development, is aggravating, and has gradually become a resistance to the construction of a new development pattern and regional coordinated development. Most of the existing studies focus on the comparison of differences between the Eastern, Central and Western regions of China, but there is little discussion on the economic gap between China's North-South economy. In addition, through the literature review, no attention has been paid to the environmental regulation factor that leads to the economic gap between the North and the South. In view of this, the study constructs a benchmark regression model and a non-linear regression model based on the balanced panel data of 285 cities in China from 2004 to 2019, explores the role that environmental regulation plays in the widening of China's North-South economy gap. The results show that, firstly, environmental regulation is significantly conducive to narrowing the economic gap between the North and the South; In addition, with the greater intensity of environmental regulation, the economic gap shows a trend of "narrowing first, expanding then", that is, There exists positive U-shaped nonlinear relationship between them. Finally, the heterogeneity of urban scale leads to significant differences in the position and shape of the positive U-shaped curve, which exists between environmental regulation and China's North-South economy gap. The test results shows that the inflection point level of the U-shaped curve in the North is higher than that in the South. Based on this, the study proposes to adjust environmental policies accordingly under regional differentiated conditions, increase financial investment in improving environmental regulation tools and promote coordinated environmental governance in the North and South regions, to promote regional coordinated and sustainable development, provide empirical evidence and theoretical reference to improve people's livelihood and well-being and ultimately achieve the goal of common prosperity.

Zhao M., Jin Y., Zhang Y.

According to urban economic theories, workers in more developed regions should have higher educational returns. However, studies on urban workers in China have shown mixed results on whether earning returns to education are higher in regions experiencing more economic growth. Meanwhile, there is a lack of evidence on this issue among migrant populations, which have rapidly increased in number during China's economic transition. To fill this void, this study investigated how educational returns among migrant workers are related to local economic development levels and industrial structures. Specifically, we used individual-level data obtained from 286 cities through the 2018 China Migrants Dynamic Survey and city-level data to conduct a multilevel linear regression analysis with random slopes. We thus found that earning returns to education were higher in cities under two conditions, including higher development and higher shares of tertiary industry. Moreover, this association was more pronounced among high-skill migrant workers than low-skill ones. As higher income is a primary driving force in migration, we suggest that future policies should further promote industrial restructuring rather than using discriminative administrative rules to guide migration flows.

Ren X.

People’s perceptions are an important part of a landscape; however, little attention is paid to acoustic comfort in landscape planning and design for various urban open spaces. This study was primarily conducted to examine the effects of dominant sound types, conversational speech and multisensory perception on the subjective evaluations of acoustic comfort of open space based on an on-site questionnaire survey in typical urban open spaces. The results showed that as the first dominant sounds moved from being mechanical and anthropogenic to being nature-related, the acoustic comfort evaluations increased significantly within the dominant sound identification dimension. The subjective loudness of the background sound level and perceived speech intelligibility were significant indicators for acoustic comfort in each type of open space within the conversational speech perception dimension; decreased subjective loudness could contribute the most to higher acoustic comfort evaluations among indicators at the same perceptual levels (on a five-point scale). Olfactory comfort, thermal comfort, sunshine, and visual aesthetic quality of view were significant indicators for acoustic comfort depending on different types of open spaces within the multisensory perception dimension; increasing positive olfactory perception to the ‘very comfortable’ level could promote higher acoustic comfort evaluations than other indicators at the same perceptual level in multisensory interactions. In terms of the combined effects of the indicators within the three dimensions and the visitors’ sociodemographic factors, the combined indicators would better fit in predicting the acoustic comfort evaluations, in which the indicators of conversational speech and the multisensory perception were key determinants with high important values contributing to acoustic comfort evaluations.

Du M., Hong B., Gu C., Li Y., Wang Y.

We selected typical residential outdoor spaces and five common sounds (birdsong, dance music, traditional opera, conversation and traffic sound) with three A-weighted equivalent continuous sound pressure level (LAeq) (60, 70 and 80 dBA) as visual-acoustic-thermal conditions. 458 elderly adults completed a subjective questionnaire while environmental parameters (meteorological parameters, illumination intensity (LUX), visible green index (VGI) and LAeq) were simultaneously measured to determine effects of visual-acoustic-thermal perceptions on overall comfort. We found that: 1) When physiological equivalent temperature (PET) was above 43.80 °C, the elderly felt thermally uncomfortable. Older adults perceived traffic sound as acoustic uncomfortable when LAeq was higher than 66.1 dBA. A higher VGI decreased the sensitivity of respondents to LUX. 2) Thermal sensation vote (TSV) and thermal comfort vote (TCV) were susceptible to the acoustic and visual environments. The influence of the visual environment and PET on acoustic sensation vote (ASV) and acoustic comfort vote (ACV) were not significant. We found a significant correlation between PET and sunlight sensation vote (SSV). 3) Acoustic and thermal comfort had a one-vote veto tendency relative to overall comfort, but no absolute veto power. Thermal comfort was the most important factor affecting overall comfort in summer while acoustic comfort was the most important in spring. 4) A binary logistic regression to predict overall comfort of elderly adults had 84.7 % accuracy, indicating a good performance.

Coleman A.F., Eisenman T.S., Locke D.H., Harper R.W.

Street-facing trees have been cited as providing a vast range of environmental benefits and also a contributing factor to community livability and quality of life. One measure of well-being that speaks directly to the livability of a city is residential satisfaction, which is represented by the social and physical environments of the particular places in which people live. Resident satisfaction can also demonstrate the degree of “fit” between one's ideal vision of a neighborhood and the actual, existing circumstances. Dimensions of resident satisfaction are less commonly studied as a variable to predict behavioral intentions or actions, and this study begins to fill that research gap by assessing resident willingness to participate in environmental restoration programs based on the streets where they live. Given the increased reliance on local residents as key actors to urban tree planting and management, this study was designed to understand the role of street-facing trees to different dimensions of resident satisfaction. We also assess the degree to which objective and subjective attributes of street trees influence resident satisfaction and explore the extent to which resident satisfaction can predict interest in a local urban tree planting initiative. Results indicate the unique role of urban trees to satisfaction and that subjectively held attitudes toward trees are important considerations when administering tree planting programs. This study also reinforces that urban tree planning and planting is a negotiation of priorities and visions between different stakeholder groups.

Song C., Sang H., Liu Y., Wang D., Suolang B., Duan G., Cao R.

The Qinghai-Tibet Plateau is cold and dry, and creating a suitable indoor environment is a prerequisite for ensuring the normal life of sojourners in mainland China. Sojourners from the plains experienced geographical spans and faced changes in the thermal and humid environments, and their thermal acclimation characteristics differed from plains and plateau residents. In this study, the intensities of thermal and humid stresses were classified according to changes in outdoor temperature and humidity caused by migration. The temperature was divided into five grades: A, B, C, D, and E, with an interval of 5 °C; humidity was divided into four grades: a, b, c, and d, with a relative humidity interval of 20%. A nationwide questionnaire survey was conducted to obtain subjective evaluations of sojourners, plains and plateau residents. Reliability and validity tests were conducted for the questionnaire. The results showed that previous exposure significantly influenced the thermal and humid expectation levels. Compared with plains residents, the proportion of sojourners who felt cold and dry increased. Sojourners from region D were less accepting of indoor temperature and had the strongest desire to improve indoor humidity, with an average humid preference vote (HPV) value of 1.7. The present study provided implications for the thermal comfort of plateau sojourners from the perspective of comprehensive demand of thermal and humid environments.

Xu M., Wu F., Moore S., Li Z.

Although the integration of migrants has been increasingly pursued by the policy makers in many countries, there remains a paucity of knowledge regarding what migrants themselves think about integration. Based on the 2014 China Migrants Dynamic Survey, this study draws upon new assimilation theory to investigate migrants' willingness to contact locals in China. Our results suggest that most migrants in China are willing to contact natives, but their willingness may not be strong. Different from the actual intergroup contact, migrants' willingness to develop intergroup contact is not affected by their socioeconomic status. Instead, such willingness might be developed based on the cultural commonalities between migrants and natives. Residential segregation can weaken migrants' willingness to contact locals even after the endogeneity bias of residential choice is controlled by using instrumental variable method and focusing on migrants who live in the housing provided by employers. This draws a darker picture of migrant integration. Previous literature explains that migrants faced with residential segregation have fewer opportunities to form intergroup contact which in turn can hamper their overall integration. Our analysis goes a step further by revealing that they may also lose their motivation to make intergroup contact – a preference that is critical to changing their disadvantaged situation.

Liu K., Xu X., Zhang R., Kong L., Wang W., Deng W.

Urban form can significantly affect building energy consumption and solar energy potential, which is essential to sustainable urban development. However, few studies have proposed a comprehensive framework to discuss this. In addition, how to bridge the gap between theory and practice, and how to combine quantitative research results with urban form design is also a matter of concern. Based on this background, this study proposes a multi-objective urban form design optimization framework based on the Grasshopper platform. Three optimization objectives were identified: minimum building energy consumption, maximum solar potential and maximum sunlight hours. Then, taking Jianhu in China as an example, the building types are extracted from the actual urban context to create blocks. The Ladybug Tools plugin is used for performance simulation, and multi-objective optimization is run in Wallacei X. Furthermore, based on the optimization process data, a correlation analysis of urban form factors with building energy consumption and solar energy potential is conducted. Finally, the research findings are integrated, and energy-efficient urban form design strategies are proposed. The research results show that a block form with excellent energy performance in Jianhu has the following characteristics: (i) The open space is often located in the center of the block. High-rise buildings are located on the west side. (ii) The block presents a layout consisting of a low south side and high north side. (iii) The orientation of the block is 15° south by westor due south. (iv) Avoid building types with large shape coefficient such as P-4, C-1, S-3 and C-2. In addition, building density (BD), open space ratio (OSR), shape coefficient (SC) and average perimeter-area ratio (PAR) have significant correlations with the total building energy use intensity of the block. For solar potential, floor area ratio (FAR), BD, the average number of floors (AF), OSR, SC, and PAR are highly correlated with rooftop PV energy generation, and sky view factor (SVF) is significantly correlated with rooftop PV energy generation.

He X., Gao W., Wang R., Yan D.

The factory area is an important part of the city. Its environment is relatively simple, mainly with large plant buildings and less vegetation, which is easy to form an extreme outdoor thermal environment. However, few studies have focused on how these changes affect outdoor thermal comfort in factory areas. In this study, through field meteorological measurements and questionnaire surveys, outdoor thermal comfort of different built environments in two factory areas in Haining, China, located in the hot summer and cold winter zone, was studied in winter. Combined with thermal comfort indices Physiological Equivalent Temperature (PET) and Universal Thermal Climate Index (UTCI), 12 observation sites in factory areas were analyzed to establish the outdoor thermal benchmark suitable for the factory area. The results show that: (1) Thermal comfort was strongly related to thermal sensation. (2) Air temperature and globe temperature were two primary factors affecting workers' thermal sensations. In addition, thermal sensation was negatively correlated with wind speed and relative humidity. (3) The built environment had a significant influence on human thermal sensation and thermal comfort; sky view factor was an important morphology parameter that affected outdoor thermal sensation, and the outdoor thermal sensation improved as it increases. (4) Neutral temperatures of PET and UTCI were 14.3 °C and 15.8 °C; neutral PET range and neutral UTCI range were 10.7–17.8 °C and 12.2–19.4 °C, respectively. These findings could serve as theoretical baselines and guidelines for factory area design.

Qiu N., Cheng J., Zhang T.

Reducing the spatial disparities and structural inequalities faced by disabled people is a global challenge in both developed and developing countries that requires an understanding of disability-driven deprivation. This study aims to develop and validate a conceptual framework for analysing the structural inequality and spatial disparity of disability-related deprivation. To achieve this goal, an Index of Disability-Related Multiple Deprivation (IDMD) based on six specific domains, including employment, education, marital status, health, services and barrier-free environments, is proposed. The IDMD was calculated at the sub-district level within the Tianjin municipality using aggregated registration information from the Tianjin Disability Database in 2020. Principal component analysis (PCA) was used to assign the weight of each indicator of IDMD. Moran I and LISA analysis were used to quantify the spatial disparity of IDMD across the municipality. Multi-Scale Geographically Weighted Regression (MGWR) was used to model the structural factors shaping the spatial disparity of disability-related deprivation in terms of gender, age, and disability types. Three key findings have been generated as follows. The spatial variability of IDMD revealed significant urban-rural disparity across the municipality, highlighting the difficulties faced by vulnerable and disadvantaged disabled people in rural areas. Men, working age groups and those with intellectual disability contributed most to the structural inequalities of IDMD. Thirdly, the location of greatest deprivation varied for different groups; working age groups faced the highest levels of deprivation in the urban centre, males faced the most deprivation in the urban fringe and those with intellectual, limb, visual, speech or mental disabilities were most deprived in rural areas. These findings reflect the complexity of structural factors affecting disability-related deprivation at the municipality scale. This study points to the need for informed, targeted welfare facilities planning and management strategies to improve spatial equity and social justice for disabled people.

Zhao X., Ju S., Wang W., Su H., Wang L.

With the rapid advance of urbanization, the rural public space in China is undergoing a drastic change. Studying the satisfaction of farmers with rural public space is of great significance for promoting the reconstruction of rural space, enhancing rural resilience, and building sustainable rural communities. This paper constructed an evaluation index system of the satisfaction of farmers with rural public space. Taking the traditional ancient village in the Chinese Loess Plateau as an example, we analyzed the differences in satisfaction of various groups of farmers with public space based on questionnaire survey data and in-depth interview data. This paper found that there is a certain degree of dislocation between the supply of rural public space and the demand of villagers in rural China, resulting in a relatively low overall satisfaction with rural public space. Among them, farmers have the highest satisfaction with production and lives public space, followed by the folk beliefs public space and entertainment public space. There are significant intergenerational and gender differences in the satisfaction of farmers with rural public space. The elders are more satisfied with the rural public space than the young people, and women are more satisfied with public space in production, life, organization and management than men. Therefore, future policies should pay attention to the modern transformation of the village traditional culture, and the requirements of different groups with rural public space. In addition, it is necessary to actively cultivate rural social organizations, enhance the ability of the village public management. • There exists dislocation between the supply of rural public space and farmers' demand in China. • There are significant intergenerational and gender differences in farmers' satisfaction with rural public space. • Older farmers are more satisfied with rural public space than younger farmers. • Women are more satisfied with rural public space of production and life, organization and management. • Promoting the sustainable development of rural public space should focus on physical and cultural transformation.

You Y., Yang X., Xu Z., Cui C., Shi F., Hong X.