The urban building plays an important role that dominates the urban thermal environment by altering the heat exchange. In this study, we coupled GIS techniques with statistical methods to investigate ...the variance of Air Temperature (AT) and how it is influenced by urban buildings in Wuhan (China). The objectives of this study are to: 1) explore the dynamic relationships of building indicators and AT at varying geographic scales, so as to determine the calculation scale for spatial configuration; 2) examine how the relationships change with time; 3) investigate the combined and individual effects of these building indicators. The indicators were chosen from the perspective of urban planning, including Floor Area Ratio (FAR), Building Density (BD), the local Moran's I of Building (MB) and Building Height (BH). Results show that an area extent of 200 m is optimal for examining the AT-building relationships. The AT-building relationships are evidenced to be significant during nighttime but negligible during daytime, and reach the strongest level at different time depending on the day's temperature levels. Results of ridge regression analyses demonstrate that, for hot days, urban buildings can jointly explain as high as 48.9% of the AT variance during summer nighttime, and the explanatory level can reach 53.4% at 1:00 a.m. Spatial configuration was proved to effectively impact on AT, which is always neglected by urban planners and decision-makers. Our findings suggest that optimizing building patterns at an appropriate scale can achieve more significant effects on mitigating nighttime UHI. The insights gained from our study have significant implications for sustainable urban development.
•The quantified building configurations were involved to explore its impacts on summer air temperature.•Scaling effects on building-temperature relationships revealed that 200 m can be a reasonable size in our study area.•Buildings only significantly amplify the air temperature during the nighttime.•Combined effects of composition and configuration would potentially achieve more effective cooling effects.
Short-term environmental exposures, including green space, air pollution, and noise, have been suggested to affect health. However, the evidence is limited to aggregated exposure estimates which do ...not allow the capture of daily spatiotemporal exposure sequences. We aimed to (1) determine individuals' sequential exposure patterns along their daily mobility paths and (2) examine whether and to what extent these exposure patterns were associated with anxiety symptoms. We cross-sectionally tracked 141 participants aged 18-65 using their global positioning system (GPS) enabled smartphones for up to 7 days in the Netherlands. We estimated their location-dependent exposures for green space, fine particulate matter, and noise along their moving trajectories at 10-min intervals. The resulting time-resolved exposure sequences were then partitioned using multivariate time series clustering with dynamic time warping as the similarity measure. Respondents' anxiety symptoms were assessed with the Generalized Anxiety Disorders-7 questionnaire. We fitted linear regressions to assess the associations between sequential exposure patterns and anxiety symptoms. We found four distinctive daily sequential exposure patterns across the participants. Exposure patterns differed in terms of exposure levels and daily variations. Regression results revealed that participants with a "moderately health-threatening" exposure pattern were significantly associated with fewer anxiety symptoms than participants with a "strongly health-threatening" exposure pattern. Our findings support that environmental exposures' daily sequence and short-term magnitudes may be associated with mental health. We urge more time-resolved mobility-based assessments in future analyses of environmental health effects in daily life.
Residential district is the important space for people living and outdoor activities. Vegetation is proved to be effectively regulate microclimate. Living in Wuhan, residents have to suffer heat ...stress in summer and strong cold wind in winter simultaneously. It is necessary to dictate vegetation types and layout in residential area to get comfortable environment both in hot summer and cold winter. This study examined the vegetation influences of residential wind environment in hot and cold seasons by using the ENVI-met model V4. Field measurement validated the performance of ENVI-met model. The simulation was based on multi-story buildings representing the current primary form of residential area in Wuhan. 3 scenarios with three tree arrangements and 8 vegetation species were simulated. Height-to-distance ratio of trees (as “Aspect ratio of trees”, ART) was used to describe the tree distribution. Results showed that the impact of vegetation on both heat environment and ventilation depended on tree arrangement, LAI, crown width and tree height. The comparison of 3 tree distributions revealed that trees with an ART < 2 should be a priority to mitigate hot environments due to the large effects on PET reduction in summer. Evergreen species with an ART < 2 also effectively decreased wind speed in winter as well as blocked direct sunlight, resulting in negative effects on PET. Tall trees with a large LAI and canopy diameter should be a priority to improve the comfort of outdoor environments.
•Trees with an ART <2 should be a priority to mitigate hot environments due to the large effects on PET reduction in summer.•Evergreen species with an ART <2 also effectively decreased wind speed in winter as well as blocked direct sunlight.•Tall trees with a large LAI and canopy diameter should be a priority to improve the comfort of outdoor environments.
Few mobility-based studies have investigated the associations between multiple environmental exposures, including social exposures, and mental health.
To assess how exposure to green space, blue ...space, noise, air pollution, and crowdedness along people's daily mobility paths are associated with anxiety symptoms.
358 participants were cross-sectionally tracked with Global Positioning System (GPS)-enabled mobile phones. Anxiety symptoms were measured at baseline using the Generalized Anxiety Disorder-7 (GAD-7) questionnaire. Green space, blue space, noise, and air pollution were assessed based on concentric buffers of 50 m and 100 m around each GPS point. Crowdedness was measured by the number of nearby Bluetooth-enabled devices detected along the mobility paths. Multiple linear regressions with full covariate adjustment were fitted to examine anxiety-environmental exposures associations. Random forest models were applied to explore possible nonlinear associations and exposure interactions.
Regression results showed null linear associations between GAD-7 scores and environmental exposures. Random forest models indicated that GAD-7-environment associations varied nonlinearly with exposure levels. We found a negative association between green space and GAD-7 scores only for participants with moderate green space exposure. We observed a positive association between GAD-7 scores and noise levels above 60 dB and air pollution concentrations above 17.2 μg m−3. Crowdedness was positively associated with GAD-7 scores, but exposure-response functions flattened out with pronounced crowdedness of >7.5. Blue space tended to be positively associated with GAD-7 scores. Random forest models ranked environmental exposures as more important to explain GAD-7 scores than linear models.
Our findings indicate possible nonlinear associations between mobility-based environmental exposures and anxiety symptoms. More studies are needed to obtain an in-depth understanding of underlying anxiety-environment mechanisms during daily life.
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•Environmental exposures were assessed along people's GPS-tracked mobility paths.•Anxiety was negatively related with green space and positively related with crowdedness.•Null linear associations were observed between environmental exposures and anxiety.•Random forest showed that associations varied nonlinearly with exposure levels.•Random forest ranked environmental exposures as more important to explain anxiety.
Exposure to transportation noise is hypothesized to contribute to anxiety, but consistent associations have not been established.
To provide a comprehensive synthesis of the literature by examining ...associations between traffic-related noise (i.e., road traffic noise, railway noise, aircraft noise and mixed traffic noise) and anxiety.
We systematically searched Web of Science, Scopus, Embase, PubMed, and PsycINFO for English-language observational studies published up to February 2020 reporting on the traffic noise-anxiety association. We appraised the risk of bias using an assessment tool and the quality of evidence following established guidelines. A random-effects meta-analysis was performed for pooled and separated traffic-related noise sources.
Of the 3575 studies identified, 11 fulfilled the inclusion criteria and 9 studies were appropriate for meta-analysis. For the pooled overall effect size between transport noise and anxiety, we found 9% higher odds of anxiety associated with a 10 dB(A) increase in day-evening-night noise level (Lden), with moderate heterogeneity (OR = 1.09, 95% CI: 0.97; 1.23, I2 = 70%). The association was more likely to be significant with more severe anxiety (OR = 1.08, 95% CI: 1.01; 1.15, I2 = 48%). Sub-group analysis revealed that the effects of different noise sources on anxiety were inconsistent and insignificant. The quality of evidence was rated as very low to low.
Our findings support the hypothesis of an association between traffic noise and more severe anxiety. More high-quality studies are needed to confirm associations between different noise types and anxiety, as well as to better understand underlying mechanisms.
A highly active graphdiyne heterojunction with highly efficient photocatalysis is designed and fabricated. This catalyst demonstrates transformative properties on photocatalysis for ammonia ...synthesis. Such excellent properties are reigned from graphdiyne incorporating Fe site‐specific magnetite resulting in a valence state transition within the catalyst. Our results show the strong advantages of graphdiyne in effectively regulating magnetite activity and coordination environments and also indicate that magnetite can selectively form two different valence tetrahedral coordination Fe and octahedral coordination Fe. The catalysts show remarkable catalytic performance for ammonia synthesis by photocatalysis, indicating transformative photocatalytic activity with an ammonia yield (YNH3
) of unprecedented level of 1762.35±153.71 μmol h−1 gcat.−1 (the highest YNH3
could reach up to 1916.06 μmol h−1 gcat.−1). This work makes full use of the structural and property features of graphdiyne and opens up a new direction for photocatalysis in the field of catalysis.
A graphdiyne heterojunction photocatalyst for ammonia synthesis reaches reaction rates of 1762.35±153.71 μmol h−1 gcat.−1 (the highest YNH3
could reach up to 1916.06 μmol h−1 gcat.−1). Our results demonstrated that the excellent properties originated from graphdiyne incorporating Fe site‐specific magnetite, resulting in a valence state transition in the catalytic process.
It is of great urgency to develop efficient, cost-effective, stable and industrially applicable electrocatalysts for renewable energy systems. But there are still few candidate materials. Here we ...show a bifunctional electrocatalyst, comprising graphdiyne-exfoliated and -sandwiched iron/cobalt layered double-hydroxide nanosheet arrays grown on nickel foam, for the oxygen and hydrogen evolution reactions. Theoretical and experimental data revealed that the charge transport kinetics of the structure were superior to iron/cobalt layered double-hydroxide, a prerequisite for improved electrocatalytic performance. The incorporation with graphdiyne increased the number of catalytically active sites and prevented corrosion, leading to greatly enhanced electrocatalytic activity and stability for oxygen evolution reaction, hydrogen evolution reaction, as well as overall water splitting. Our results suggest that the use of graphdiyne might open up new pathways for the design and fabrication of earth-abundant, efficient, functional, and smart electrode materials with practical applications.
Self‐active metal‐free graphdiyne (GDY) is used, which has a precise chemical structure, as a model carbon‐based metal‐free electrocatalyst to assess its activity in the hydrogen evolution reaction ...(HER) and to understand the origin of electrocatalytic performance at the atomic level. The studies reveal that the unusual electrocatalytic properties of GDY originate from its unique nanostructure, which can simultaneously provide highly active sites for hydrogen adsorption and facilitate the electron‐transfer process for proton reduction. Accordingly, GDY can act as a metal‐free efficient HER electrocatalyst with Pt‐like HER activity, but with long‐term durability superior to that of Pt/C under the wide pH range (from acidic to basic). To the best of knowledge, such HER performance is better than that of other reported metal‐free electrocatalysts and most transition‐metal electrocatalysts—even Pt‐based ones.
The metal‐free graphdiyne (GDY) can act as an efficient hydrogen evolution reaction (HER) electrocatalyst with Pt‐like activity, but with long‐term durability superior to that of Pt/C from acidic to basic conditions. The results reveal that the unusual electrocatalytic properties of GDY originate from its unique nanostructure, which can simultaneously provide maximum active sites and facilitate electron‐transfer for proton reduction.
The first utilization of nitrogen‐doped graphdiyne (NGDY) as an efficient catalytic promoter for hydrogen evolution reaction (HER) is reported. X‐ray powder diffraction and X‐ray photoelectron ...spectroscopy studies indicate the presence of strong interactions between NGDY and MoS2, which should effectively facilitate the charge transport behavior and improvement of the HER kinetics. The creative hybridization of MoS2 and NGDY endows such heterostructure with structural and compositional advantages for boosting the catalytic activity (low overpotential of 186 mV at 10 mA cm−2 and Tafel slope of 63 mV dec−1) and extraordinary stability (higher than all reported MoS2‐based materials and even better than that of commercial Pt and almost all benchmarked electrocatalysts). All of the results not only demonstrate that NGDY can be used as an effective catalytic promoter for hydrogen production, but also provide new strategy for fabricating efficient water‐splitting electrodes.
The creative hybridization of MoS2 and nitrogen‐doped graphdiyne endows such heterostructure with structural and compositional advantages and highly associated interactions, which effectively facilitate the charge transport behavior and hydrogen evolution reaction (HER) kinetics, leading to greatly enhancement in the intrinsic HER catalytic activities and outstanding stability in acidic conditions.
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