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The article discusses the changes in the landscape of Washington, D.C., by U.S. soldiers during the U.S. Civil War in order to defend the city from invasion from Confederate forces and the environmental change that it wrought. It examines the rural aspect of the Washington, D.C. landscape that threatened invasion, particularly the potential use of the Potomac River heights. According to the article, U.S. forces constructed forts, batteries.

The failure of experts and lay people to understand each other has been fueling conflict around the environmental clean-up of the many sites in the United States that are contaminated by the nuclear weapons program. This mutual distrust was exacerbated by the culture of secrecy surrounding the atomic weapons program during World War II, and later by the innate culture of bureaucracy in the federal agencies that have sprung up since then. A prime example of this problem can be found in the regulation of chronic long-term risk from low-level radiation exposure affecting communities in Missouri's North St. Louis County. This case study illuminates this divide, and illustrates opportunities to close it. [ABSTRACT FROM AUTHOR]

During the 2008 Olympic Games, after years of environmental regulations, two months of short-term measures, and opportune weather, Beijing measured a record number of "blue sky days," at the same time reassuring international athletes and journalists the air was safe for competition and Beijing residents. We use this case to understand how environmental objectives are achieved in sport. Using Bruno Latour's object-oriented political ecology, we describe the events leading to, during, and after the Games. We argue environmental objectives are possible when environments are made public; this means environmental objects--such as skies and particulate matter--must be assembled and then articulated or, in other words, brought forward and made capable of speech. [ABSTRACT FROM AUTHOR]

This study looks at the hosting of the 2014 Fédération Internationale de Football Association World Cup in Rio de Janeiro and, based on research drawing on environmental psychology and studies of liminality, hypothesizes that the perceived celebrative atmosphere in the city increases subjective well-being of host city residents (cariocas). Data were collected via in-person intercept surveys from 221 and 218 cariocas before and during the event, respectively. There was an increase in subjective well-being from before the event to during the event. The results of two-group path modeling revealed further that there was a positive impact of the perceived celebrative atmosphere in the host city on residents’ subjective well-being during the event; the effect was weaker (though still positive) for the time period when the event was not being hosted. Initiatives may build upon the atmospheric elements in a city to increase subjective well-being of residents, particularly in the context of event hosting. [ABSTRACT FROM AUTHOR]

While climate change is a global challenge, its impact is generally felt in local communities, particularly cities. The impact of climate change in urban settings is exacerbated by the built environment, high energy usage, air pollution and urbanisation, among other factors. Due to urbanisation, more children will be born and raised, or migrate to live in cities. Children in cities are vulnerable to the impact of climate change due to their physiology and developmental needs. City authorities are expected to utilise their constitutional and legislative powers in climate governance to protect children from the impact of climate change. The central inquiry of this article is to explore how city-level climate law and policy protects children in the context of climate change. Using Kenya and South Africa, as key examples, it illustrates that cities have constitutional powers and legislative authority to plan, implement and govern in certain climate-related functional areas and that could be leveraged to ensure the protection of children. The discussion of cities, children's rights and climate change governance has global significance given the trends of urban growth in the present and coming decade. [ABSTRACT FROM AUTHOR]

Whether the urban heat island (UHI) is affected by air pollution in urban areas has attracted much attention. By analyzing the observation data of automatic weather stations and environmental monitoring stations in Beijing from 2016 to 2018, we found a seasonally dependent interlink of the UHI intensity (UHII) and PM2.5 concentration in urban areas. PM2.5 pollution weakens the UHII in summer and winter night, but strengthens it during winter daytime. The correlation between the UHI and PM2.5 concentration has been regulated by the interaction of aerosol with radiation, evaporation and planetary boundary layer (PBL) height. The former two change the surface energy balance via sensible and latent heat fluxes, while the latter affects atmospheric stability and energy exchange. In summer daytime, aerosol‐radiation interaction plays an important role, and the energy balance in urban areas is more sensitive to PM2.5 concentration than in rural areas, thereby weakening UHII. In winter daytime, aerosol‐PBL interaction is dominant, because aerosols lower the PBL height and stabilize atmosphere, weaken the heat exchange with the surrounding, with more heat accumulated in the urban areas and the increased UHII. Changes in evaporation and radiation strengthen the relationship. At night, the change of UHII more depends on the energy stored in the urban canopy. Aerosols effectively reduce the incident energy during daytime, and the long‐wave radiation from the buildings of urban canopy at night becomes less, leading to a weakened UHII. Our analysis results can improve the understanding of climate‐aerosols interaction in megacities like Beijing. Plain Language Summary: A detailed understanding of the relationship between PM2.5 and the urban heat island (UHI) effect is significant for climate change adaption, planning, and sustainable development in urban regions. While Beijing is among the cities with the highest population densities and fastest urbanization rates in China and even the world, the impacts of PM2.5 pollution on UHI remain unclear, and the works using different methods (observations or models), observational data (stations or satellites) and the selecting procedures to classify stations deliver different results. This study demonstrates that the UHI intensities in summer and winter, respectively, exhibit weakening and strengthening tendency as PM2.5 concentration increases. These effects are modulated by aerosol‐radiation interaction in summer and winter, and aerosol interaction with planetary boundary layer and evaporation in winter. Our analysis improves the understanding of interaction of urban climate and air pollution. Key Points: With increasing PM2.5, summer urban heat island intensity (UHII) weakens and winter UHII strengthensWinter PM2.5 pollution weakens the UHII at night but strengthens it during daytimePM2.5 affects UHII via aerosol‐radiation interaction in summer and via aerosol‐planetary boundary layer interaction in winter [ABSTRACT FROM AUTHOR]

Many novel research algorithms have been developed to analyze urban heat island (UHI) and UHI regional impacts (UHIRIP) with remotely sensed thermal data tables. We present a comprehensive review of some important aspects of UHI and UHIRIP studies that use remotely sensed thermal data, including concepts, datasets, methodologies, and applications. We focus on reviewing progress on multi-sensor image selection, preprocessing, computing, gap filling, image fusion, deep learning, and developing new metrics. This literature review shows that new satellite sensors and valuable methods have been developed for calculating land surface temperature (LST) and UHI intensity, and for assessing UHIRIP. Additionally, some of the limitations of using remotely sensed data to analyze the LST, UHI, and UHI intensity are discussed. Finally, we review a variety of applications in UHI and UHIRIP analyses. The assimilation of time-series remotely sensed data with the application of data fusion, gap filling models, and deep learning using the Google Cloud platform and Google Earth Engine platform also has the potential to improve the estimation accuracy of change patterns of UHI and UHIRIP over long time periods. [ABSTRACT FROM AUTHOR]

As a result of urbanization, natural surfaces are replaced by artifcial surfaces that trap heat such as buildings, pavements and asphalt, so residential areas have higher temperature values than rural areas. This effect, defned as the urban heat island, causes an increase not only in air temperature but also in the subsurface and groundwater. Groundwater temperature values were measured during one year in an area approximately 53 km2 consisting of different types of settlement areas to determine the urban heat island effect on the subsurface of Kütahya. As a result of the measurements, urban heat island maps were prepared. It was observed that the groundwater temperature anomalies increased towards the urban/industrial areas. The difference of groundwater temperature in urban/rural areas reached up to 7°C by well. This heat energy increasing with the effect of urban heat island can be used in the heating processes of buildings by utilizing systems called "shallow geothermal energy". For this reason, the heat potential of the alluvial aquifer under Kütahya was calculated. The theoretical heat potential values of the this aquifer range between 1.64 x 1013 kJ K-1 and 5.55 x 1013 kJ K-1 with a mean value of 3.50 x 1013 kJ K-1. It is thought that urban heat island maps and the heat potential calculations of the aquifers may be important parameters for applicability of shallow geothermal systems in the city center of Kütahya. [ABSTRACT FROM AUTHOR]

Urban areas generally have higher near‐surface air temperature and lower air humidity than rural areas. Little is known about how heat stress, the combined effect of high air temperature and high humidity on human physiology, will be affected by future urban land expansion. Here we use a mesoscale numerical weather prediction model to examine the effects of urban land expansion from 2000 to 2050 on heat stress (measured as wet‐bulb globe temperature, WBGT) in the urban areas of China, India, and Nigeria, which are projected to account for one‐third of global urban population growth through 2050. Our results show that urban expansion slightly reduces heat stress during the day (∼0.2°C) but substantially intensifies it at night, by ∼1°C on average and by up to 2–3°C in five mega‐urban regions (MURs). These effects exist with or without climate change induced by rising concentrations of greenhouse gases (GHGs). Installing cool roofs—an urban heat island mitigation measures—can reduce the daytime WBGT by 0.5–1°C, partially offsetting the heat stress conditions caused by GHG‐induced climate change. However, even with cool roofs, the nighttime WBGTs are higher by 0.3–0.9°C over the whole countries studied, and by 1–2°C in the MURs under the urban expansion scenario, compared to the situation in which urban areas remain unchanged. These results show that future urban expansion and heat island mitigation can result in potential daytime benefits but also persistent nighttime risks. Key Points: Urban land expansion by 2050 will slightly reduce heat stress during the day but substantially intensifies it at nightAbout half of the outdoor nighttime urban heat stress increases will persist even with cool roofs installed at large‐scalePossible complimentary adaptation measures include improving building insulation to reduce indoor heat stress [ABSTRACT FROM AUTHOR]

The effectiveness of urban hydrological processes in mitigating the urban heat island (UHI) effect and human thermal stress in the megacity of Nanjing during an extreme heat wave event (6th–10th August 2013) was assessed using Weather Research and Forecasting Single‐Layer Urban Canopy Models. The inclusion of urban hydrological processes improved model performance, with more reasonable diurnal cycles and smaller mean errors, root mean square errors, and normalized root mean square errors for meteorological variables. Through evaporative cooling, urban hydrological processes can greatly increase specific and relative humidity, while reducing near‐surface and surface temperatures, wind speed, and planetary boundary layer (PBL) height, and the cooling and wetting effects could affect the entire PBL, especially in low‐intensity residential areas. Urban hydrological processes can effectively mitigate both the near‐surface and surface UHI effect. The city‐wide mitigation effectiveness of near‐surface UHI ranged between 0.9°C and 1.1°C throughout the day, while the city‐wide mitigation effectiveness of surface UHI at noon reached ∼5°C. The maximum reduction of near‐surface and surface UHI in low‐intensity residential areas reached 1.3°C and 10.0°C, respectively. Changes in heat stress indices indicate that the cooling effect improves human thermal comfort at night, while the increased humidity outweighs the cooling effect and exacerbates human thermal discomfort during daytime. The city‐wide thermal stress increased by up to 0.4°C, 0.2°C, and 0.5°C during daytime and decreased by up to 0.4°C, 0.3°C, and 0.6°C at night for wet‐bulb globe temperature, apparent temperature, and humidity index, respectively. Key Points: The cooling and wetting effects of urban hydrological processes are most significant during daytime and in low‐intensity residential areasUrban hydrological processes effectively mitigate both the near‐surface and surface urban heat island effectUrban hydrological processes improve human thermal comfort at night but exacerbate it during daytime under heat‐wave conditions [ABSTRACT FROM AUTHOR]

This paper presents an impact of hydro-meteorological extreme events and urban catchment to water quality in small rivers in Białystok (Poland). The results from a five-year study have taken into account droughts, continuous precipitation, and storm precipitation causing flash floods. Extreme hydro-meteorological events has a different impact on the physical and chemical parameters of water. It was found that the largest change in water quality occurs on the 2nd day after the rainfall and changed concentration of some chemical parameters persists for a long time. The majority but, what's important, not all of them are diluted after floods and concentrated after droughts. Flash flooding results in a large increase concentrations of DOC and selected forms of phosphorus. Higher values of EC, Eh, Mg2+, HCO3-, Cl-, SiO32-, NO3-N, TN were observed during drought compared to the average values from 2014–2018. A high degree of naturalness of the river valley and increased water retention results in a decreased concentration of NH4+-N, DOC and phosphorus forms. The buffer zone plays an important role in limiting the inflow of pollutants and nutrients from the catchment area. That is why it is worth undertaking restoration of river valleys in urban areas. [ABSTRACT FROM AUTHOR]

Anthropogenic activities, by far the largest source of NOx into the atmosphere, induce a weekly cycle of NO2 abundances in cities. Comprehensive analysis of the 2005–2017 OMI NO2 dataset reveals significant weekly cycles in 115 of the 274 cities considered. These results are corroborated by a full year of high-resolution TROPOMI NO2 observations. The OMI dataset permits us to identify trends in the weekly cycle resulting from NOx emissions changes. The data show a clear weakening of the weekly cycle over European and U.S. cities, an evolution attributed to the decline in anthropogenic emissions and the resulting growing importance of background NO2, whereas NO2 lifetime changes also play a minor role. In particular, the Sunday NO2 columns averaged over all U.S. cities are found to increase, relative to the weekly average, from 0.72 during 2005–2007 to 0.88 in 2015–2017. The opposite tendency is recorded in regions undergoing rapid emission growth. Multiyear simulations over the U.S. and the Middle East using the chemistry-transport model MAGRITTEv1.1 succeed in capturing the observed weekly cycles over the largest cities, as well as the observed long-term trends in the weekly cycle. [ABSTRACT FROM AUTHOR]

Cool roof is the technique that delivers higher solar reflectance and higher thermal emittance than standard roofing products. Its fastest developing applications in the built environment comes with various benefits, such as reducing the urban heat island effect by decreasing surface temperatures, which reduces the flow of heat into the atmosphere, and offsetting warming caused by greenhouse gases. In this study, a Cool Coating Paint has been experimented while the impact was measured in terms of an integration with the Solar PV technology. This research investigated cool roof applications on building's rooftop together with PV panels for the Middle East climatic conditions, and its impact on the electricity generation. The preliminary findings of the experimental study indicated that there is a likely impact of 5–10% improvement of electricity generation with the cool roof applications. [ABSTRACT FROM AUTHOR]

Climate change is likely to increase the risks related to heat waves in urban areas. We map spatial pattern of heat wave vulnerability and risk in the Helsinki metropolitan area in southern Finland. First, we assess differences that zoning, i.e., differences in spatial units of analysis, and weighting, i.e., weights given to indicators when constructing the index, cause in map production. Second, we evaluate how maps of consensus and certainty could pave the way for visualizing and assessing uncertainties in risk and vulnerability indices. For vulnerability, we use socioeconomic data using 5 different zoning options and 11 different weighting options. For risk, we add two extra layers to vulnerability maps: hazard map showing the spatial pattern of heat based on Landsat satellite images and exposure map showing the spatial pattern of population. We found that when different zoning options are used, the spatial pattern of vulnerability may differ dramatically. In risk maps, the differences between zoning options are smaller. Contrary to previous literature, differences in indicator weighting alter the final maps slightly. The consensus and certainty maps show their potential, e.g., in pointing out areas which may have both high risk/vulnerability and high certainty for risk/vulnerability. Finally, we discuss other possibilities in tackling the uncertainties in mapping and propose new avenues for research. [ABSTRACT FROM AUTHOR]

The article discusses U.S. government support for an aqueduct project in Los Angeles, California, between 1904 and 1941. According to the article, the U.S. government's endorsement of the project stemmed from the conservationist policies of former U.S. president Theodore Roosevelt during the early 20th century. The article discusses plans devised by the city of Los Angeles to draw water from Owens River. The article also discusses the role of the U.S. Reclamation Service in the project.

An essay is presented on the environmental pollution, humans, and animals. It discusses the author's thoughts on the ecological consequences of a filtration project designed by the Albuquerque, New Mexico, Metropolitan Arroyo and Flood Control Authority (AMAFCA) and a Power of New Mexico (PNM) electricity plant, particularly on the birds of the area.

In this work an Operational Street Pollution Model was used to define the minimum number and the expected position of the stations for an air quality network with three monitoring stations to be installed in Battipaglia (Italy). The features of the urban background, the type of daily traffic, all the meteorological parameters typical of the investigated area, were implemented in the software to simulate the hourly emissions. These allowed to determine the feasible number of air sampling station and their best location points. [ABSTRACT FROM AUTHOR]

To keep up with world Rapid population growth in many countries including Egypt, the Egyptian government adopted polices to establish new urban communities, which many of them located in severe conditions of hot arid climate. However, the urban plans of those new cities do not prioritize the local climate considerations in its planning, which negatively effect on the thermal performance of urban spaces. In recent decades, greater attention was given to study the relationship between urban features and the local climate, developing mitigation and adaptation strategies with the aim of improving the thermal performance of urban spaces. So, this study aims to formulate a matrix of guidelines for urban heat islands mitigation strategies concerning urban geometry that can be helpful in improving the thermal performance of outdoor spaces in the existing new Egyptian cities -which allocated in hot arid climate zone, to enhance thermal comfort in these spaces. To achieve this goal, a comprehensive review, and analysis of the impacts of different urban geometrical thermal mitigation strategies on outdoor spaces in hot-arid climate, is presented. The geometrical variables of urban spaces which have been investigated in the reviewed researches classified into two main groups (squares and plazas, canyons). The geometrical variables of squares and plazas include; side compactness, and Sky View Factor (SVF). Canyons geometrical variables are; SVF, aspect ratio and side profile shape. These variables depend on the features of those spaces which resulting from the urban pattern form and geometry. These guided values have been applied theoretically and practically on three real cases, to illustrate the mechanism of matrix guidelines applying on urban outdoor spaces thermal behavior initial evaluation and determine the most suitable environmental mitigation strategies directly. Applying of guidelines help in mitigating thermal behavior of plaza with about 18.73 k degree and the canyon space with 3.28 k degree. The discussion of this research clearly reflects the importance of urban planning guidelines that can be applied to help enhancing outdoor thermal comfort. This study is useful in controlling the climatic consequences of urban planning at an early stage. [ABSTRACT FROM AUTHOR]

Interactions between humans and nature are understood to be beneficial for human well-being. In cities, urban green spaces are believed to provide many benefits to urban populations in terms of mental and emotional well-being. Through a case study of 60 urban green spaces in Birmingham, United Kingdom, this article investigates the spatial and temporal variation of the emotions experienced by individuals whilst using urban green spaces. Using a dataset obtained from Twitter as the basis for emotional explorations, sentiment analysis was performed on over 10,000 tweets to ascertain the positivity/negativity of individuals. Positive responses were more common than negative responses across all seasons, with happiness and appreciation of beauty being the common positive emotions identified. For the negative responses, fear and anger were present in similar amounts, with fewer tweets indicating sadness and disgust. Our findings show that Twitter data is a viable source of information to researchers investigating human interaction and emotional response to space in cities. Such information has implications for urban planners and park managers, enabling the creation of evidence-based spaces which enhance positive outdoor experience. Limitations in using Twitter data are discussed and these should be considered in future research. [ABSTRACT FROM AUTHOR]

Research in urban ecology depends on frameworks that meaningfully integrate our understanding of biophysical and social change. Although the coupled nature of urban ecosystems is widely accepted, the core mechanisms we use to integrate the social and biophysical aspects of urban ecosystems - their social-ecological feedbacks - are poorly understood. This paper considers how feedbacks are used to conceptualize social-ecological change, noting their utility and their limitations. In so doing, we suggest that coproduction provides a meaningful alternative to feedbacks, one that captures not only the structure-function relationships usually assumed in studies of biophysical landscape change, but also the structure-agency relationships that facilitate our most comprehensive understanding of social change. By addressing both the stepwise forms of transformation that a feedback approach captures and the simultaneous forms of transformation captured by a coproduction approach, a more comprehensive assessment of the ways that social and ecological change take place is afforded. We contend that thinking in terms of coproduction is essential for moving beyond the interdisciplinary approach that usually guides urban ecology models, toward a more integrated, trans-disciplinary approach. [ABSTRACT FROM AUTHOR]

Although outdoor thermal comfort has gained increasing research attention, meteorological conditions and thermal sensation in different urban settings in high-density cities have not been systematically studied from the perspective of urban planning and design. Considering the potential relationship between environmental quality and thermal sensation in outdoor spaces— an emerging topic in perceived comfort, this study offers a new approach for planning and design for climate resilience in cities. This paper presents the results of an outdoor thermal comfort survey conducted on hot summer days in Hong Kong. Diverse patterns of PET-comfort ratings relationships were found in different urban settings. The study revealed that air temperature, subjective assessments of solar radiation and wind environment were strong determinants of thermal sensation and evaluation. In our analysis, wind condition showed a significant indirect effect on comfort through subjective perception. Statistical modelling showed that subjective perceptions on microclimate condition and comfort are moderated by various aspects of environmental quality. The findings of this study help inform future design for climate resilience in outdoor urban spaces in hot-humid subtropical cities. [ABSTRACT FROM AUTHOR]

Abstract The correct contextualisation of urban measurements is one of the challenges that urban climate researchers have been dealing with for decades. The Local Climate Zones scheme (LCZs) emerges as a system for characterising these measurements from the thermal perspective. The rapid embracing of the LCZs by researchers from many disciplines, altogether with its adoption for other purposes such as planning, has led to an inexistent or, at its best, flexible use of the source area definition. This practice might call into question the contextualisation of many measurements, highlighting the imperative need to shed light on the source area methods within the urban context. In this study, a systematic review is conducted to compile previous experiences in which the source area was applied in the built environment. Results obtained from the systematic search are summarized and presented according to three scales: the inertial sublayer, the roughness sublayer, and the urban canopy layer. These previous experiences are studied according to their methodological contribution to the source area definition, emphasizing those studies that have considered this concept altogether with the LCZ scheme. This review aims at promoting the knowledge about footprint methodologies and its correct application within the LCZs. Highlights • The source area definition within urban contexts was systematically reviewed. • Differences in the footprint adoption are related with the atmospheric scale. • The embracement of the source area by LCZ studies is low and very heterogeneous. • Choosing, estimating and reporting the source area should be standardised. • Further research is needed to develop reliable footprint tools within the UCL. [ABSTRACT FROM AUTHOR]

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Highlights • Facade greening is beneficial for daytime urban cooling and heat island mitigation. • The degree of cooling benefit is mostly dependent on greened facade ratio (GFR). • For a high-density Hong Kong, ∼1 °C temperature drop requires 30–50% GFR. • Same GFR ensures daytime thermal comfort improvement by at least one class. Abstract To improve outdoor thermal environment and reduce indoor energy use, passive techniques including façade greenery have been suggested. In high-density cities like Hong Kong, buildings' surface area is much greater than the roof and ground surface areas combined, offering a huge vertical surface platform for greening. However, scientific evidence to assert the thermal benefit from this greening option especially at neighborhood scale is still very few. Therefore, this study was designed to provide such evidence using results from validated ENVI-met model simulation. Thereafter, parametric study was conducted to investigate the quantity and location of facade greening required for potential air cooling and thermal comfort improvement of a neighborhood of varying densities. Model validation results revealed an acceptable modelling of facade surface temperature, air temperature, relative humidity and wall-emitted long-wave fluxes. From the parametric study, we found that 30–50% of facades in the high-density urban setting of Hong Kong must be greened to potentially cause ∼1 °C reduction in both daytime and nighttime air temperature while the same could help improve daytime pedestrian thermal comfort by at least one thermal class. We also established that higher greened facade ratio will be required to obtain similar thermal benefits in low and medium density urban settings. Also, realized benefits at pedestrians' height can be enhanced when the vertical greening facilities are placed along podium than tower heights. Lastly, practicable urban planning recommendations were presented for the attention of urban planners and landscape architects. [ABSTRACT FROM AUTHOR]

Highlights • Individual types of green land use have a different impact on UHIM in different PFs. • The forests' configuration and composition affect the urban heat island magnitude. • The share of forest does not affect the UHIM in all PFs in the same direction. • Higher forest share is associated with a lower UHIM in Southern and Eastern Europe. • Higher share of agricultural land use reduces the UHIM in North Europe. Abstract The phenomenon of increased temperature in cities compared to their rural environs, also referred to as urban heat island, is one of the most evident anthropogenic climatic modifications. Introducing green spaces and vegetation is the fastest, simplest, and a highly effective way of mitigating and adapting urban temperature conditions. The primary goal of the presented research is to identify the interrelationship between urban heat island magnitude (UHIM) and urban green infrastructure extent, shape, and distribution on European scale comparing different green space planning traditions – planning families (PFs). The UHIM for the European cities was calculated based on a reconstructed MODIS LST dataset of a period of ten years. The reasons for the arrangement of UHIMs according to PFs and green land use are not easily explained and are certainly influenced by a number of various conditions in different PFs. UHIM increases with the longitude of cities. In some of the PFs, the relation between the UHIM and land use proportion is characteristic for certain land uses, but a considerable difference between PFs regarding land use proportion with significant impact on UHIM can only be noted in case of a forest. The configuration and composition of the forest correlate with UHIM with statistical significance, but the share of the forest does not affect UHI in all PFs in the same way. While a higher proportion of forest, higher largest patch index, higher mean patch area, higher edge density and higher proportional landscape core is associated with a lower UHIM in the New member and Mediterranean PFs, the relationship in other PFs is reversed. Information on general patterns of UHIM occurrence in relation to urban green infrastructure characteristics could help urban planners and politicians introduce changes on the local level, which would help providing nature-based solutions for the mitigation of the UHI phenomenon. [ABSTRACT FROM AUTHOR]

Extensive green roofs are urban construction systems that provide thermal regulation and sound proofing for the buildings involved, in addition to providing an urban heat island mitigation or water retention. On the other hand, policies towards reduction of energy consumption, a circular economy and sustainability are core in the European Union. Motivated by this, an experimental study was carried out to evaluate the environmental risk assessment according to release levels of polluting elements on leachates of different green roof substrate mixtures based on recycled aggregates from construction and demolition waste through (i) the performance in laboratory of two procedures: compliance and percolation tests and (ii) an upscaled experimental leaching test for long-term on-site prediction. Four plots were built on a building roof and covered with autochthonous Mediterranean plants in Córdoba, South of Spain. As growing substrate, four mixtures were used of a commercial growing substrate with different proportions of a fine mixed recycled aggregate ranging from 0 to 75% by volume. The results show that these mixtures were classified as non-hazardous materials according to legal limits of the Landfill Directive 2003/33/CE. The release levels registered in extensive green roofs were lower compared to the laboratory test data. This shows how laboratory conditions can overestimate the potential pollutant effect of these materials compared to actual conditions. [ABSTRACT FROM AUTHOR]

The adverse health impact of air pollution is becoming more serious. The purpose of this study is twofold: One is to analyze the effect of air pollution and temperatures on human health by analyzing the number of deaths from cardiovascular disease in Seoul, Korea; the other is to determine what impact the location of a monitoring site has on the results of a health study. For this latter purpose, air pollution and temperature monitors are sited at three locations termed green, public, and residential. Then, a decision tree model is used to analyze factors linked with deaths occurring at each monitoring site. The results show that the environmental temperatures before death and the PM2.5 concentrations on the day of death are highly linked with the number of deaths regardless of the monitoring location. However, results are most accurate with residential data. The results of this study can be used as base data for a similar analysis and ultimately, as a guide to minimize the health impact of air pollution. [ABSTRACT FROM AUTHOR]

Abstract China has become the world's largest energy consumer, accounting for approximately 30% of global CO 2 emissions. City contributions make up 84% of China's commercial energy consumption. However, energy consumption data for most Chinese cities are not accessible. Many studies have focused on the estimation of carbon emissions at the provincial or national level; city-level carbon emissions are not well studied. In order to solve this problem, this research constructed a top-bottom method for city-scale energy-related carbon emissions estimation in China. Typically, cities are considered the constituent units of a province. Relying on provincial energy balance tables and utilizing the available city-level socioeconomic data as indicators, we scaled down provincial energy consumption to the city level. We compared our estimation results with city-level point-source data, and found that for the 41 Chinese cities to which we applied this method, the difference was within 10%, while for 25 of these cities, the difference was within 5%. Thus, we believe our method is reasonably accurate. We also subdivided the city carbon emissions into three major energy categories (coal-related, oil-related, and gas-related) and found that the difference could be attributed mainly to coal-related energy emissions. The results of the uncertainty analysis indicated that the uncertainty of the coal emission factor was the largest, thus demonstrating that it is critical not only to choose appropriate indicators to characterize coal-based industrial carbon emissions, but also to identify accurate emission factors for coal-related fossil fuels. Both analyses demonstrated China's coal-dominant energy structure. We believe our method is practical and can provide detailed data support for the establishment of city-level carbon emission inventories, furthermore, it will also be helpful for Chinese cities to negotiate carbon reduction responsibilities and allocating carbon reduction tasks. Highlights • A new city-scale CO2 emission estimation method was proposed. • Spatial differences of energy consumption in three different regions were analyzed. • Uncertainties caused by three types of fossil fuels' emission factors were analyzed. • City CO2 emission data was provided for formulating climate policies. [ABSTRACT FROM AUTHOR]

Abstract This paper develops a new paradigm to analyze the eco-efficiency of Yangtze River Economic Belt (YREB) in China and makes a first empirical attempt at examining whether the eco-efficiency in urban agglomerations (UA-s) outperform Non-urban agglomerations (Non-UA-s), or driving the Non-UA-s in promoting eco-efficiency using a dataset of 108 prefectural-level cities during 2003–2014. The main findings are as follows. First, the eco-efficiency of YREB gradually increases during the study period. Cities in UA-s with higher eco-efficiency experience an increasing spatial agglomeration while those in Non-UA-s show a slight downward shift. Second, in terms of eco-efficiency, both statistical test and econometrical test confirm that cities in UA-s outperform those in Non-UA-s. Third, the global and club convergence of eco-efficiency in YREB is ascertained. Forth, the eco-efficiency of UA-s exerts backwash effects on those in Non-UA-s, along with decreasing the convergence speed of eco-efficiency. Special issues are briefly discussed, lastly. Highlights • A new analysis paradigm is developed to explore the YREB's eco-efficiency. • Temporal-spatial evolution and empirical tests are conducted, indicating a proof that eco-efficiency in urban agglomerations outperform that in Non-urban agglomerations. • Urban agglomerations have backwash effects and slight constraints to Non-urban agglomerations in terms of eco-efficiency. • Some special issues are discussed. [ABSTRACT FROM AUTHOR]

Abstract As a major consumer of fossil fuels, the transportation sector in Shanghai presents a wide range of problems, including air pollution, noise, and traffic congestion. This study aims to explore the energy substitution effect based on a trans-log production function to evaluate the contribution of each input factor to sectoral output, and reveal the substitution possibilities between capital, labor, and energy. To deal with a multicollinearity problem, we adopt ridge regression to obtain the coefficient of each variable under the appropriate penalty value. The bootstrap method is used for making statistical inferences, and the 95% confidence interval is obtained with 1000 bootstrap samples. The empirical results demonstrate the following. (1) The output elasticities of capital (0.13–0.15), labor (0.24–0.25), and energy (0.43–0.48) are positive and show an increasing trend over the study period. (2) The substitution elasticity between labor and energy is the highest among the input factors (around 1.0095), with a slight decreasing trend. (3) The substitution elasticity between energy and capital ranges from 1.0018 to 1.0021, and the substitution elasticity between capital and labor is infinitely close to 1. Graphical abstract Image 1 Highlights • We analyze the energy substitution effect of Shanghai's transportation sector. • Elasticity of substitution between energy and labor trended down during 2000–2014. • Substitution between energy and labor can occur by mechanization and automation. • Elasticity of substitution between energy and capital ranges from 1.0018 to 1.0021. • Energy consumption can be cut by increasing capital inputs. [ABSTRACT FROM AUTHOR]

Despite the great promise of hybrid solar-wind-biomass energy systems to power future sustainable cities, complexities associated with their optimal planning and design limit their wide-scale implementation. This study provides a novel systematic framework to identify optimal hybrid renewable solutions for urban areas at neighborhood scales. In particular, we examine the role of economies of scale in the techno-economic feasibility and environmental performance of hybrid renewable systems. For demonstration, we assess the impact of the economics of scale (at the neighborhood scales of 1/500, 1/250, and 1/100 of the city's electrical load) on the life-cycle costs of optimal hybrid renewable systems for Vancouver (Canada). Our results indicate that the total net present cost (NPC) of the optimized systems were 59, 116 and 290 million USD, while the levelized costs of electricity (COE) for the three studied scales were almost identical (0.300–0.307 USD/kW h). By comparing the proposed scenarios regarding gross atmospheric emissions, land requirements and economic performance, the mid-scale (1/250) with 6.3 MW of solar PV and 3 MW gasifier (~ 117 t/day biomass wastes) was preferable to the larger (1/100) and smaller (1/500) scale systems. Results from this study can help decision-makers in creating effective policies and mechanisms to advance the integration of hybrid renewable energy systems in cities. [ABSTRACT FROM AUTHOR]

The data of lightning flash density, total rainfall, surface temperature, surface humidity, convective available potential energy (CAPE) and particulate matter up to 10 μm in size (PM 10 ) over Nanning, China from July 2009 to December 2017 were studied on a yearly/monthly/hourly scale. It was found that the correlation between lightning and precipitation varies in various seasons, and the influencing factors of lightning/precipitation are different in various seasons. CAPE is the most important influencing factor of lightning on an hourly scale. Quantitative analysis showed the joint effects of surface temperature, surface humidity, CAPE and PM 10 on lightning. For dry cases, lightning increases with increasing PM 10 for the low value of PM 10 , and decreases with increasing PM 10 for the high value of PM 10 . While the situation is the opposite for wet cases. It was also found that surface temperature and CAPE can affect the correlation between aerosol and lightning. [ABSTRACT FROM AUTHOR]

Changes in climate extremes are studied based on the daily precipitation in North Sikkim Himalaya. The Coupled Model Intercomparison Project Phase 5 (CMIP5) Global Climate Models GCMs) and their Representative Concentration Pathways (RCPs) and India Meteorological Department (IMD) daily precipitation dataset are used for future and observed time periods, respectively. The purpose of this study is to examine the copula-based probabilistic behavior of precipitation extremes over the eastern Himalayan region. Seven extreme combinations were developed based on the eight defined precipitation indices. The extreme combination designates the duration, frequency and amount of heavy and weak precipitation in the same year. Statistical downscaling model (SDSM) and copulas are used for downscaling and bivariate behavior of precipitation extremes, respectively. Trend analysis result exhibits that the precipitation and its extremes (intensity, wet days, heavy precipitation days and very heavy precipitation days) are increasing significantly during 2006–2100. The spatial distributions of joint return period (JRP) of (T5, T10 and T20) marginal values are quite same during 1979–2005. In addition, the co-occurrences of heavy and weak precipitation would be more frequent in future, resulting higher risk of floods and droughts within the same year. The North Sikkim region may be at high risk of floods because precipitation extremes are increasing along with co-occurrence of flood and drought in the same year. [ABSTRACT FROM AUTHOR]

Drought severity in regions North and Northwest of Rio de Janeiro state (SRJ) was evaluated using the Standardized Precipitation Index (SPI) for the monthly (SPI-1) and annual (SPI-12) scales, as well as its relationship with El Niño - Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO). Data of 14 rainfall stations from a time series considering the period of 1967–2013 was used. The SPI calculation was based on the SCI package available at R software version 3.4.2 library. SPI categories used are Very Dry, Moderately Dry and Extremely Dry associated with the hot and cold phases of the PDO, followed by ENSO events according to the Oceanic Niño index (ONI) in El Niño region 3.4 using an interaction matrix. The matrix was evaluated by the coefficients of Kendall ( τ ), Sperman ( ρ ), Pearson ( r ) and R 2 determination, followed by Willmott's concordance index ( d ), Standard Error of Estimation ( SEE ) and Student's t- test. The intense activity of La Niña in the cold 1st phase of the PDO increased rainfall with greater intensity in the Northwest region compared to the North. In the 2nd cold phase of the PDO, the events of El Niño, La Niña and Neutral years of the ENSO mutually contribute to the changes in rainfall regime of both regions. The most frequent SPI categories are Moderately Dry and Extremely Dry. SPI-1 was efficient in perceiving extreme droughts, while SPI-12 results were not significant in the revealing of extreme droughts. In addition, there was no relational pattern through statistical indexes between droughts detected by SPI, ENSO and PDO. Nevertheless, when ENSO cycles were persistent within both phases of the PDO, droughts occurred, mainly on the monthly scale. [ABSTRACT FROM AUTHOR]

Abstract Urban heat island (UHI) shows thermal intensification in urban areas compared to surrounding areas. Land surface temperature (LST) has been widely applied in assessing UHI. However, due to limitations of the LST retrieval method, few researchers attempted to track the long-term dynamics of UHI and their responses to progressive urbanization process based on Landsat series data. In this study, we improved the retrieval method to extract the average UHI intensity of Hangzhou city core in 1990–2010, and explored the dynamics of UHI composition and configuration in response to urbanization. Google Earth Engine (GEE) was applied to calculate the average UHI intensity in the study area. Hangzhou city core was heating up in study period with extensive conversions from neutral and cool area to heated area. The expansion of heated area initially radiated from the original urban core in linear configuration, and subsequently expanded to infill areas away from the core by replacing neutral and cool area. The significant differences in average UHI intensity between different land use and land cover (LULC) types can be observed: urban land had the highest value whereas forest and water body registered the lowest. The expansion of urban land at the expense of natural land had exceeded a threshold to induce spillover of heat energy from the former to the latter. The findings can inform nature-based solutions to optimize the thermal environment and livability of fast-growing subtropical cities. Highlights • Google Earth Engine calculated average UHI intensity to avoid cloud-cover data gaps. • Hangzhou city core converted notably from neutral & cool to heated area in 1990–2010. • Urban land had highest average UHI intensity whereas forest and water body the lowest. • Heated-area expansion increased its high overlay rate with urban land through time. • Urban-land expansion and natural-land shrinkage induced heat spilling to the latter. [ABSTRACT FROM AUTHOR]

Developing reliable frameworks to estimate the potential of CO 2 emission abatement and its associated costs merits urgent attention. This study aims to estimate the potential as well as macroeconomic costs of CO 2 emission abatement in Beijing. Using the industrial economy as the basis, multiobjective programming and genetic algorithm are integrated into the input–output analysis. Several important findings have been gathered in the study: (1) The abatement cost varies between $259.97 and $535.46 per ton at different rates of economic growth. (2) A reinforced emission abatement target can induce higher macroeconomic costs. (3) An inverse U-shaped relationship between CO 2 reduction cost and GDP growth rate was found. When GDP growth rate is above the threshold value of 7%, marginal abatement costs decrease rapidly in parallel with GDP growth. When the GDP growth rate is below 7%, the marginal abatement cost increases significantly with economic growth. (4) Industries that have the highest and least potential of abatement have been identified. For effectively reducing CO 2 emissions, Beijing needs to promote economic restructuring to maximize the potential of emission abatement and also fulfil the emission abatement target in a cost-effective way. This paper provides a quantitative approach to rationalize the policy design process of enacting emission targets and recommends cost-effective abatement strategies. [ABSTRACT FROM AUTHOR]

PM 2.5 samples were collected simultaneously at three urban sites including Beijing (BJ), Tianjin (TJ), Shijiazhuang (SJZ) and one background site Xinglong (XL) from June 2014 till April 2015. Typical polar organic aerosol tracers including 2-methylglyceric acid, 2-methyltetrols, 3-hydroxyglutaric acid, anhydrous saccharides and phthalic acid were analyzed by gas chromatography-mass spectrometry. Both Isoprene secondary organic aerosol (SOA) tracers and pinene SOA tracers had higher mass concentrations at background site than those at urban sites. But they showed different seasonal variations. The former had the highest mass concentration in summer while the latter had the highest mass concentration in spring. Anhydrous saccharides and phthalic acids at urban sites had higher mass concentrations than those at background site and showed higher mass concentration in autumn and winter, respectively. Corresponding estimated secondary organic carbons (SOCs) showed similar variation trends with tracers. In general, biogenic sources had more influence on background site while urban sites were more affected by anthropogenic sources. [ABSTRACT FROM AUTHOR]

Air quality data such as Particulate Matter PM2.5 collection near the ground is difficult, particularly in small complex regions. This study aims to introduce a PM2.5 prediction algorithm based on measurements from Unmanned Arial Vehicle (UAV)-based sensing system and validate the model at a specified low altitude. Observations were applied around 1.6 km² area in University Putra Malaysia. This study uses an empirical method via applying amassed records of PM2.5 and meteorological parameters to produce a predictive Geographically Weighted Regression (GWR) model. An accuracy value is computed from the probability value given by the regression analysis model. To validate this approach, we have utilized training and testing data. To evaluate and validate the suggested model, we applied the model to the training set. The obtained result indicated that there is a good statistical correlation, and demonstrated that the characteristics obtained by analysis are able to predict the concentration of PM2.5. [ABSTRACT FROM AUTHOR]