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The research interest of urban researchers and geographers in the relationship between urban environments and happiness has been increasing. Previous studies have mostly focused on people's long-term overall wellbeing. However, there is limited evidence that momentary happiness is associated with immediate urban environments. This study provides new evidence on this issue. 144 participants living in Guangzhou, China, were asked to repeatedly self-report their momentary happiness through ecological momentary assessment (EMA) and the day reconstruction method (DRM). The microenvironment variables were captured by portable sensors, while the built environment variables were captured by associating the GPS response locations with objective spatial data. The results indicate that momentary happiness is influenced by immediate microenvironment variables and built environment characteristics including temperature, noise, PM2.5, population, POI density, POI types and street intersections. On the other hand, the use of different sizes of contextual units affects the results. The built environment in 100 m buffers and the microenvironment has higher explanatory power for momentary happiness recorded by EMA than the built environment in 500 m buffers. Similarly, the temporality of the contextual influences also affects the results. Urban environment features have higher explanatory power for real-time momentary happiness recorded by EMA than recalled momentary happiness recorded by DRM. These results also strongly corroborate the results of recent studies on the uncertain geographic context problem (UGCoP) and partly explain the inconsistency in the results of past research. [ABSTRACT FROM AUTHOR]

Background: Numerous urban villages (UVs) and frequent infectious disease outbreaks are major environmental and public health concerns in highly urbanized regions, especially in developing countries. However, the spatial and quantitative associations between UVs and infections remain little understood on a fine scale. Methodology and principal findings: In this study, the relationships between reported dengue fever (DF) epidemics during 2012–2017, gross domestic product (GDP), the traffic system (road density, bus and/or subway stations), and UVs derived from high-resolution remotely sensed imagery in the central area of Guangzhou, were explored using geographically weighted regression (GWR) models based on a 1 km × 1 km grid scale. Accounting for 16.53%–18.07% of residential area and 16.84%–18.02% of population, UVs possessed 28.55%–38.24% of total reported DF cases in the core area of Guangzhou. The density of DF cases and the DF incidence rates in UVs were 1.81–3.13 and 1.82–3.06 times of that of normal construction land. Approximately 90% of the total cases were concentrated in the UVs and their buffering zones of radius ranged from 0 to 500 m. Significantly positive associations were observed between gridded DF incidence rates and UV area (r = 0.33, P = 0.000), the number of bus stops (r = 0.49, P = 0.000) and subway stations (r = 0.27, P = 0.000), and road density (r = 0.39, P = 0.000). About 60% of spatial variations in the gridded DF incidence rates were interpreted by the different variables of GDP, UVs, and bus stops integrated in GWR models. Conclusions: UVs likely acted as special transfer stations, receiving and/or exporting DF cases during epidemics. This work increases our understanding of the influences of UVs on vector-borne diseases in highly urbanized areas, supplying valuable clues to local authorities making targeted interventions for the prevention and control of DF epidemics. [ABSTRACT FROM AUTHOR]

This study focused on characterizing the oral bioaccessibilities and human health risks of eight heavy metals (Cd, Pb, Cr, Ni, Cu, Zn, Fe, and Mn) in surface-exposed lawn soils from 28 urban parks in Guangzhou. The physiologically-based extraction test (PBET) method was used to assess bioavailability (in gastric and intestinal phases) and human health risk was assessed via statistical modelling (carcinogenic risk assessment, hazard quotients and hazard indices). Mean bioaccessibilities of Cd, Pb, Cr, Ni, Cu, Zn, Fe, and Mn from all soil samples were 50.90 ± 17.67%, 5.81 ± 1.67%, 7.12 ± 3.24%, 17.91 ± 18.34%, 11.93 ± 2.88%, 34.33 ± 10.02%, 1.68 ± 0.48%, 26.71 ± 5.06%, respectively. The concentrations of most heavy metals were higher in the gastric phase, except for Cr and Ni which remained higher in the intestinal phase. Principal component analysis revealed that the bioaccessibilities of the heavy metals could be split into three groupings, based on the urban park of soil origin. The carcinogenic risk probabilities for Pb and Cr were under the acceptable level (< 1 × 10 −4 ) for both adults and children. The hazard quotient and hazard index values indicated no significant risk of non-carcinogenic effects to children or adults exposed to Guangzhou urban park soils. This research will help inform further risk assessment and management of heavy metal contaminants in urban environments. [ABSTRACT FROM AUTHOR]