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Below the boundary layer, the air pollutants have been confirmed to present the decreasing trend with the height in most situaitons. However, the disperiosn rate of air pollutants in the vertical profile is rarely investigated in detail, especially through in-situ measurement. With this consideration, we employed an unmanned aerial vehicle equipped with portable monitoring equipments to scrutinize the vertical distribution of PM 2.5. Based on the original data, we found that PM 2.5 concentration decreases gradually with altitude below the boundary layer and demonstrated an obvious linear correlation. Therefore, the vertical distribution of PM 2.5 was quantified by representing the distribution of PM 2.5 with the slope of PM 2.5 vertical distribution. We used backward trajectories to reveal the causes of outliers (PM 2.5 increasing with altitude), and found that PM 2.5 in the high altitude came from the southwest. Besides, the relationship between the vertical distribution of PM 2.5 and various meteorological factors was investigated using stepwise regression analysis. The results show that the four meteorological factors most strongly correlated with the slope values are: (a) the difference in relative humidity between the ground and the air; (b) the difference in temperature between the ground and the air; (c) the height of the boundary layer; and (d) the wind speed. The slope values increase with increasing the difference in relative humidity between ground and air and the difference in temperature between the ground and the air, and decrease with increasing boundary layer height and wind speed. According to the Random Forest calculations, the ground-to-air relative humidity difference is the most important at 0.718; the wind speed is the least important at 0.053; and the ground-to-air temperature difference and boundary layer height are 0.140 and 0.088, respectively. [Display omitted] • PM 2.5 concentration decreases linearly with height below the boundary layer. • The slope is obtained to reflect the dispersion rate of PM 2.5 in vertical profile. • Relative humidity shows notable effect on PM 2.5 distribution in vertical profile. • The dispersion rate shows increasing trend in the morning and then decreases after 9a.m.. [ABSTRACT FROM AUTHOR]

Knowledge of spatio-temporal patterns of global land surface evapotranspiration (ET) is essential for understanding the exchanges of energy, water and carbon between the earth surface and atmosphere and responses to human activities, climate changes, and extreme weather events. This paper comprehensively reviewed accuracies and spatio-temporal patterns of 25 state-of-the-art global datasets of land surface ET from 2001 to 2018, where the global and/or local distributions of annual mean, interannual variability, and annual trend for both ET and its components [canopy transpiration (Ec), soil evaporation (Es), and interception evaporation (Ei)] were investigated. Overall, 23 out of the 25 ET products exhibited good consistency with monthly eddy covariance observations at 83 globally distributed sites, with the root mean square error (RMSE) ranging from ∼19 mm/month to ∼29 mm/month and the coefficient of determination (R2) ranging from 0.45 to 0.76. Comparatively, almost all ET products were in good agreement with the water balance-based observations at 137 large basins worldwide, with the R2 of >0.60 and the RMSE ranging from ∼200 mm/yr to ∼260 mm/yr. In general, remote sensing-based, machine learning-based, and hybrid-based ET products generally agreed better with site observations than reanalysis-based products. Global annual ET ranged from 530 mm/yr to 700 mm/yr with the ensemble mean of 628 ± 44 mm/yr (excluding areas of the urban, barren, wetlands, permanent snow and ice, and water bodies). Most products captured consistent global spatial distributions of annual mean, interannual variability, and annual trends of land surface ET and its components. Both mean annual ET and its components generally decreased with increasing latitudes though with an increasing trend in time. Interannual variability also decreased with increasing latitudes and with an increasing trend in time, but only in the Northern Hemisphere; these signals were not clear in the Southern Hemisphere. Most of the 25 products presented unimodal shapes of frequency curves, and displayed a sequenced multi-year mean of seasonal ET of JJA > MAM > SON > DJF. The Ec exhibited the largest mean annual value, in most areas followed successively by the Es and Ei. The ET products displayed a relatively high consistency in the spatial distribution of the Ec/ET with higher estimates of Ec/ET in the Southern Hemisphere than in the Northern Hemisphere. This up-to-date review could benefit the understanding of the states and advances of global ET datasets, afford scientific instruction for the development and improvement of ET models and products, and serve as a basis for the choice of ET datasets for specific use. • Spatio-temporal patterns of 25 global datasets of land surface ET are reviewed. • The 25 global ET products are validated against EC- and WB-based observations. • Global and local patterns for both ET and its components are investigated. [ABSTRACT FROM AUTHOR]

Vehicle emission has been regarded to the major source of air pollution in urban area. Especially, the emissions originating from container diesel trucks (CDTs) constitute a significant portion of road transportation emissions in port city. However, the instantaneous measurement of CDTs emission in real road situation remains limited. In this study, we employed a portable emission measurement system (PEMS) to measure the real-world emissions of CDTs that meet the China IV and China V standards on highway and port roads. Based on the data, the impacts of vehicle speed, acceleration, and vehicle specific power (VSP) on CO 2 and NOx emission rates are investigated. Additionally, random forests is employed to explore the interplay of driving, engine, and external factors on vehicle emission rates, as well as to predict these rates. Finally, the emission factors under diverse driving conditions are examined. The results indicate that elevated CO 2 and NOx emission rates are primarily observed during instances of low and medium-speed acceleration on highway. On port road, the distribution of high CO 2 and NOx emission rates are relatively scattered. The relationship between the emission rates of CO 2 and NOx and VSP follows a third-order polynomial function. Engine power, engine speed, and VSP exhibit a strong correlation with CO 2 and NOx emission rates. Remarkably, the CO 2 and NOx emission factors on highway for China V CDT have decreased by 58.04% and 55.13%, respectively, compared to China IV CDT. [Display omitted] • High emission of CO 2 and NOx appeared during acceleration at low and medium speeds. • CO 2 and NOx emissions strongly link to VSP in a third-degree polynomial. • Driving factors explain 63% of CO 2 emissions in China V container diesel trucks. • The China V container diesel truck emits 46.6% less CO 2 than the China IV truck. [ABSTRACT FROM AUTHOR]

Previous evaluation of flood risk overlooks the behavior and capacity of private stakeholders, thus limiting the application of adaptation policies. This study presents an agent-based model, applied to Miami-Dade County, FL, as the case study, to explore the public and private interaction in coastal flood adaptation and mitigation. The decision making of individuals' adaptive behavior is simulated based on the prospected theory under households' risk perception, insurance policies, and the local flood mitigation. The NFIP and private insurance policy are simulated separately to reflect the flood insurance market. Our results show that households' risk mitigation behaviors are clustered in high-risk coastal areas, including Miami-Beach and the east coast of the County. The overall flood risk is still high in the southern part of the County. To better reflect the flooding risk and address the affordability issue, a voucher coupled house elevation program could improve the insurance take-up rates as well as reduce the overall flood risk in the area. Results also indicate that private insurance would slightly increase if the NFIP's insurance rates increase. Afterward, four adaptation scenarios in response to future sea level rises are examined by considering the voucher-based insurance program and the local adaptation actions. Compared with the high-risk reduction but low coverage mitigation plan, more extensive coverage of public adaptation would better improve the overall adaptation outcome of the County, which indicates the importance of public participation in local risk mitigation and urban governance. • An agent-based model is developed to study the public and private interaction in flood adaptation. • The risk mitigation behaviors of large quantities of households are explored in Miami-Dade County. • The NFIP and private insurance policy are simulated separately to reflect the flood insurance market • Households' risk mitigation behaviors are irrational and clustered in high-risk coastal areas. • Scenario analysis indicates the effective public adaptation actions. [ABSTRACT FROM AUTHOR]

Abstract Previous studies on air pollution exposure have mostly focused on the urban, regional, national and global scales, but the outcomes cannot well support risk assessments in urban communities. To determine how the urban form and meteorology influence the air pollution distribution at a neighborhood scale (2 km*2 km), we performed a fine-scale investigation of a typical air pollutant (i.e., PM 2.5) by mobile measurements in two communities in the inner and outer cities of Shanghai, China. The PM 2.5 mass concentrations and potential impacting factors, such as PM 2.5 background levels, road networks, traffic volumes, meteorological parameters, building heights and land use types, were collected at a 10 m spatial resolution, and their relationships were analyzed using both a generalized additive model (GAM) and land use regression (LUR). The modeling results showed that the GAM outperformed LUR in both study areas, with a higher adjusted R2 and a lower RMSE. The PM 2.5 was found to have drastic variations at the neighborhood scale, which was primarily driven by spatial patterns of the PM 2.5 background levels and traffic volumes. The GAM-based PM 2.5 concentration surface clearly disclosed the heterogeneous variation of the PM 2.5 mass concentrations in each community, and demonstrated the prominent influence from the nearby highway, especially in the central urban area. This study provides the first empirical evidence of the exposure heterogeneity of the air pollution on a neighborhood scale, which can assist planners and policymakers in evaluating planning strategies with a full consideration of reducing local air pollution. Highlights • Mobile measurements of PM 2.5 concentrations are performed in two neighborhoods of Shanghai. • Generalized additive models outperform land use regressions for assessing PM 2.5 variations. • PM 2.5 of high values are mainly distributed alongside highways up to 100–300 m. • Building height with wind speed primarily determines PM 2.5 variations in the central urban area. • PM 2.5 variations in the suburban area are mainly impacted by regional emission sources. [ABSTRACT FROM AUTHOR]

Abstract Sea-level rise (SLR) has drawn unprecedented attention from coastal communities around the world. In fact, many are already being affected and, in response, SLR vulnerability assessments have increasingly emerged in the US as the local communities' first attempt on the adaptation planning agenda. However, to date, little is known about these early planning endeavors in terms of how vulnerability is conceptualized and operationalized. By reviewing the current local SLR vulnerability assessments in the US, we find that most are only focusing on their biophysical exposure to SLR overlooking other important vulnerability factors including sensitivity and adaptive capacity. The limited number of SLR scenarios and the lack of consideration for extreme events are also considered as the major deficiencies. To fill these gaps, we propose a conceptual vulnerability assessment framework to operationalize the full concept of vulnerability and test it through a case study in the Tampa Bay region, Florida. By comparing the vulnerability results of the common practice with our proposed framework, we find large variances in the resulting findings stressing the importance of selecting the proper assessment approach. This paper finally concludes with urban planning and governance implications and future research directions. Coastal planner and managers wanting to improve their understanding of the communities' vulnerability to SLR will benefit from this study. Highlights • How coastal localities conceptualize and assess vulnerability varies. • Most of the existing sea-level rise vulnerability assessments only consider exposure. • A conceptual sea-level rise vulnerability assessment framework is developed. • The assessment approach can significantly affect vulnerability findings. [ABSTRACT FROM AUTHOR]

Ridesourcing, or on-demand ridesharing , is quickly changing today's travel. Recently, research has linked socio-demographics to ridesourcing use. However, little of the research has focused on the impacts of built environment, an important factor to consider in understanding travel behavior. This study applied Geographically Weighted Poisson Regression (GWPR) and examined the spatial relationships between built environment and ridesourcing demand. We used 2016–2017 ridesourcing trip data from a transportation network company (TNC), RideAustin , in Austin, Texas. By capturing the spatial heterogeneity, the GWPRs considerably improve modeling fit compared to the global models. Modeling results present strong relationships between ridesourcing demand and built environment variables (i.e., density, land use, infrastructure, and transit accessibility). More importantly, the results demonstrate significant spatial variations of the effects of both built environment and socio-economic variables and geographic trends from urban to suburban neighborhoods. Overall, these findings suggest that built environment factors have significant impacts on ridesourcing demand, and it is important to consider the spatial context. The study provides useful insights for understanding ridesourcing use as a function of built environment and have important implications for transportation planning, demand modeling, and urban governance. [ABSTRACT FROM AUTHOR]

Abstract Air quality in megacities and its correlation with urban form have become a priority, since numerous cities worldwide are encountering a development bottleneck due to air pollution. This paper analyzed the spatial variations in 8 air pollutants among 18 ambient air monitoring stations across Shanghai based on continuously hourly mass concentration data from 28 days in February 2017. In each of the 18 stations, we created a buffer zone with a radius of 1 km, and derived 18 quantified features of the urban form including points of interest and environmental information by the geographic information system and the Baidu Map program interface. Then, the 18 stations were clustered into 3-level groups by using the k -nearest neighbor method according to every pollutant and urban form. Results showed that the spatial variation differed per pollutant, as did urban form. PM 2.5 concentrations were high in the western and low in the eastern of Shanghai, which can be explained by regional influences and the distance from East China Sea. PM 10 showed a relatively high level in the developed urban areas, and high buildings with a similar height in these areas significantly restrain the dispersion of PM 10. The spatial variations of the 6 gaseous pollutants mainly depend on local human activities and transport-related emissions. The distance to primary road, standard deviation of building floors, and average building floors were the top 3 urban form features influencing the spatial variations of all pollutants. Wind ventilation was identified as a critical index for air quality-oriented urban design. Highlights • Spatial variability is analyzed for 8 air pollutants among 18 monitoring stations. • The cluster analysis is performed to correlate air pollutants and urban form. • Spatial variation of PM 2.5 relies critically on regional impacts and the distance to East China Sea. • High buildings with a similar height significantly restrain the dispersion of PM 10. • Gaseous pollutants strongly correlate to local activities and transport-related emissions. [ABSTRACT FROM AUTHOR]

Road intersections have the potential to pose an additional exposure risk to surrounding dwellers or commuters; however, knowledge of fine-scale variations of traffic pollutants especially PM 2.5 and black carbon (BC) remains limited. To investigate them, we conducted a three-point synchronous observation at an intersection in Shanghai in winter and spring. Real-time monitors with one-minute intervals were used to obtain the pollutant and meteorological data while gasoline and diesel vehicle volumes were manually collected every five minutes. Observational results showed that the average PM 2.5 on the downwind roadside increased by approximately 9% in both seasons and that the average BC increased by 70% in winter and 97% in spring compared to those of the local background site. PM 2.5 displayed a similar diurnal variation among the three sites at the intersection, but in contrast to PM 2.5 , the BC variation was more strongly correlated to the diurnal traffic cycle. Generalized additive models further identified the background variation as the major contributor to the variations in both pollutants at the intersection, explaining 77–99% and 33–43% of the variance in ln ( P M 2.5 ) and ln ( B C ) , respectively. Air pressure and solar radiation were the next top determinants of pollutant variations. Relative humidity combined with air temperature in winter and with dew-point temperature in spring also had a significant impact. Roadside BC was sensitive to traffic from the windward direction, while PM 2.5 was mostly influenced by the external pollution driven by westerly winds. In contrast to gasoline vehicles, diesel vehicles were verified to provide an appreciable contribution of approximately 9% to roadside BC variations in spring. [ABSTRACT FROM AUTHOR]

An innovative end-plate connection is proposed by welding an H-shaped steel corbel to the end-plate and the end-plate is connected to the special T-shape concrete-filled steel tubular (CFST) column using a number of high-strength bolts. This paper presents experimental and numerical studies on the seismic performance of the new end-plate connection between T-shaped CFST columns and reinforced concrete (RC) beams with slabs. Tests of seven specimens are conducted: a specimen is tested under the monotonic loading in order to obtain the load-displacement curve and the development of strains until the failure; and six specimens are tested under cyclic loading. The seismic behaviour of the connections in terms of strength, ductility, energy dissipation, strength degradation and stiffness degradation are evaluated. The experimental results demonstrate that the proposed connections exhibit good seismic performance and that the length of the H-shaped steel corbel and the diameter of the high-strength bolt played important roles in improving the seismic behaviour of the connections. A finite element (FE) model based on ABAQUS is developed and validated by the experimental results for the numerical investigation of the seismic behaviour of the proposed end-plate connections. It has been found that the reinforcement ratio of beam and the concrete strength of the beam and slab can affect the seismic performance of the specimens, but the effect of the axial compressive force ratio of the column on the seismic performance can be neglected. [ABSTRACT FROM AUTHOR]

Bamboo vinegar, a natural liquid manufactured from bamboo, has been regarded as a potential antibiotic substitute in animal production. In this study, we evaluated the effects and mechanism of bamboo vinegar powder (BVP) on the antioxidant ability of pigs. A total of 40 Duroc × Landrace × Yorkshire healthy pigs (80.88 ± 0.82 kg) were selected and randomly allocated into 5 different groups: control group (CG, fed with basal diets); antibiotic group (AG, fed with antibiotic-supplemented diets); 0.5% BVP group (0.5% BVG, fed 0.5% BVP-supplemented diets); 1.0% BVP group (1.0% BVG, fed with 1.0% BVP-supplemented diets) and 1.5% BVP group (1.5% BVG, fed with 1.5% BVP-supplemented diets). With the BVP-supplemented diets, the activities of glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) in the blood increased ( P < 0.05), the activities of GSH-Px and catalase (CAT) in the liver also increased ( P < 0.05), the activity of total antioxidant capacity (T-AOC) increased both in the liver and blood ( P < 0.05), but the activity of iNOS in the liver and blood decreased ( P < 0.05). Moreover, the gene expressions of Nuclear related factor 2 ( Nrf2), catalytic subunit of glutamate-cysteine ligase ( GCLC), NAD(P)H quinone dehydrogenase 1( NQO1), heme oxygenase 1 (HO1), Glutathione peroxidase ( GSH-Px) and Catalase ( CAT) in the liver were also increased due to the addition of BVP ( P < 0.05). In conclusion, BVP supplementation improved the antioxidant ability of the liver in finishing pigs by increasing the activity of some antioxidant enzymes and decreasing the activity of oxidative stress enzymes. These changes may be due to the activation of the Nrf2-Are pathway. [ABSTRACT FROM AUTHOR]