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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]

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]

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]

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]

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]

Individual footprint indicators are limited in that they usually only address one specific environmental aspect. For this reason, assessments involving multiple footprint indicators are preferred. However, the interpretation of a profile of footprint indicators can be difficult as the relative importance of the different footprint results is not readily discerned by decision-makers. In this study, a time series (1997–2012) of carbon, water and land footprints was calculated for industry sectors in the Beijing region using input-output analysis. An integrated environmental footprint (IEF) was subsequently developed using normalization and entropy weighting. The results show that steep increases in environmental footprint have accompanied Beijing's rapid economic development. In 2012, the Primary Industry had the largest IEF (8.32); however, the Secondary Industry had the greatest increase over the study period, from 0.19 to 6.37. For the Primary Industry, the greatest contribution to the IEF came from the land footprint. For the Secondary and Tertiary Industries, the water footprint was most important. Using the IEF, industry sectors with low resource utilization efficiency and high greenhouse gas emissions intensity can be identified. As such, the IEF can help to inform about industry sectors which should be given priority for modernization as well as the particular footprints that require priority attention in each sector. The IEF can also be helpful in identifying industry sectors that could be encouraged to expand within the Beijing region as they are especially efficient in terms of value adding relative to IEF. Other industries, over time, may be better located in other regions that do not face the same environmental pressures as Beijing. [ABSTRACT FROM AUTHOR]

The 2014 follow-up of the Anniston Community Health Survey (ACHS II) consisted of 338 surviving participants from the 2005–2007 baseline study (ACHS) who had previous polychlorinated biphenyl (PCB) measurements, were not pregnant, and were not institutionalized. Questionnaires and blood samples provided the demographic, personal history, and chemical concentration data of the Anniston residents. Approximately 51% of participants were African American, 72% were female, and the mean age was 63 years old. The objectives of this study were to provide an exposure assessment of dioxin-like chemicals in the ACHS II participants and compare the measurements with the general United States (U.S.) population via the National Health and Nutrition Examination Survey (NHANES). Stratified analyses revealed significantly higher average total dioxin toxic equivalencies (TEQs) among African Americans compared to Whites (33.1 vs. 19.2 pg/g lipid), and in females compared to males (29.8 vs. 17.0 pg/g lipid). When adjusting for age, sex, and race in linear regression, we found ACHS II participants to have significantly higher total dioxin TEQ than the general 2014 U.S. population that we estimated for using half-life and NHANES 2003/04 data (most recent NHANES individual samples data), by 16.7 pg/g lipid. Principal component analyses showed that non-ortho and mono-ortho PCBs were separated from the other dioxin-like chemicals among the Anniston residents, whereas the chemicals were all clustered together for estimated NHANES 2014. The concentrations of dioxin-like chemicals, especially non-ortho and mono-ortho PCBs, in Anniston residents who resided near the former PCB production plant were higher than those in the general U.S. population. Although data strongly supported this difference, these inferences are limited because NHANES 2013/14 data were unavailable and we used estimated NHANES 2014 levels that we imputed from NHANES 2003/04 data in conjunction with half-life values estimated from Milbrath et al., 2009. [ABSTRACT FROM AUTHOR]

China suffers from severe hazy conditions, and the central government has introduced a mandatory target responsibility system to curb haze pollution. It is of policy importance to explore whether the mandatory target responsibility system is effective at improving the performance of environmental governance in China. However, studies have tended to ignore the impact of mandatory targets on PM 2.5 concentration control. To fill this gap, this study, based on a nationwide dataset of 267 Chinese cities, applies a novel two-stage regression approach to identify the causal relationship between mandatory targets and PM 2.5 concentration reduction by solving the endogeneity bias. The results demonstrate that a 1% increase in mandatory PM 2.5 performance targets helped reduce the annual average PM 2.5 concentrations by 0.5283 μg/m 3 on average after nearly 2 years of implementation. Moreover, the PM 2.5 concentrations of Chinese cities showed strong positive spatial dependence, and when spatial dependence is controlled, the average marginal impact of mandatory targets on PM 2.5 concentration reduction decreased to 0.1998 μg/m 3 . This research confirms the spatial agglomeration of PM 2.5 concentrations across Chinese cities and highlights the effectiveness of the mandatory target responsibility system for the control of China's haze pollution. [ABSTRACT FROM AUTHOR]

Highlights • Data on the impact of four trees’ species on the UHI are obtained. • Three physiological and seven microclimatic parameters are studied. • Differences in cooling performance among the four trees’ species are assessed. • Ficus microcarpa has the best cooling performance (reduced PET by 32.4 °C). • Tree planting implications are discussed from a microclimatic perspective. Abstract Tree morphology and characteristics are quite different among different tree species, leading to large differences in cooling performance across tree species, particularly across different climatic regions. To obtain microclimatic characteristics and data on the influence of common subtropical tree species on the outdoor thermal environment, this study investigates, with field measurements, three physiological indices (leaf transpiration rate, leaf surface temperature, and leaf reflectance) and seven microclimatic parameters (solar radiation, long wave radiation, mean radiant temperature (Tmrt), ground surface temperature, air temperature, relative humidity, and wind speed) characterizing four common tree species in Guangzhou: Ficus microcarpa , Mangifera indica , Michelia alba, and Bauhinia blakeana. The Physiological Equivalent Temperature (PET) is calculated with the Rayman 12 tool to assess human thermal comfort. Special focus is set on the differences between these parameters in the presence and absence of tree cover. The results are as follows: Ficus microcarpa has the best cooling performance (reduced solar radiation by 1050 W/m2, reduced Tmrt by 14.8 °C, reduced PET by 32.4 °C). These trees have also some negative effects: reducing wind speed (2.83 m/s) and increasing long wave radiation (55 W/m2). It is expected that these data and results will shed some light on tree planting implications in subtropical areas. [ABSTRACT FROM AUTHOR]

Urban heat island affects cities climate and results in higher air temperature with respect to the surrounding rural zones. Anthropogenic heat released by human activities exacerbates this phenomenon which impacts on environmental and energy fields. Air conditioning is commonly used to achieve comfort indoor conditions in the warmer urban climate but it is also one of the serious cause of the urban heat islands. The heat rejected by the condensers of air conditioning systems, increases the air temperature next to the buildings in which they are installed. In this paper a system consisting of a ground-source heat pump, a low temperature thermal network and a series of electric heat pumps, is analysed. The thermal grid is the heat source/sink for the water to water electric heat pumps that are installed at each end-user of a multi-purpose six floors building located in Naples (Southern of Italy). In cooling mode the condenser heat is discarded in the ground by the ground source heat pump that operates between the lower temperature thermal grid and the borefield. In the heating period the thermal network is heated by the ground source heat pump, that draws energy from the ground. The models simulating the energy conversion systems, the low temperature thermal network and the building, are implemented in the dynamic simulation software TRNSYS 17. A first advantage of the proposed configuration is the avoided interaction with the outside air and the corresponding mitigation of the urban heat island phenomenon. A second one is the higher coefficient of performance of the water to water electric heat pumps, operating with a lower temperature gap with respect to the case in which the electric heat pumps interact with the outside air. Furthermore, the interaction with thermal grid allows high seasonal performance due to the low fluctuation of the temperature with respect to the air. Finally this energy efficient system could be simply installed not only in the new buildings, but also in refurbishments. The proposed system is compared with a conventional one installed in each dwelling consisting of an air to water air conditioner for cooling operation and a boiler for heating. Interesting global and local environmental advantages are obtained. [ABSTRACT FROM AUTHOR]

Bogota is a Latin American megacity located at an average altitude of 2600 m in the tropical Andes. It registers frequent episodes of poor air quality due to high PM 10 concentrations. The carbonaceous fraction is the main PM 10 component (>50%), but there is a lack of specific studies analyzing the characteristics and temporal variability of organic carbon (OC) and elemental carbon (EC) aerosols. In this study, daily samples (24±1h) were collected from June 2015 to May 2016 (a total of 308 samples) at an urban background site during an El Niño year, and the quartz filters were analyzed using a thermal-optical method. Results showed that EC and organic matter accounted for ~60% of the PM 10 mass. The OC and EC averages were 8.92 ± 4.52 μg/m 3 and 3.25 ± 1.59 μg/m 3 , respectively. The months with the highest average OC values were January to March, while EC concentrations were relatively constant throughout the year. Regarding daily values, the highest mean concentrations of OC (10.2 ± 5.13 μg/m 3 ) and EC (3.73 ± 1.74 μg/m 3 ) were obtained on Thursdays, and the lowest on Sundays (OC = 6.67 ± 3.04 μg/m 3 and EC = 2.46 ± 0.94 μg/m 3 ). The OC/EC ratio ranged from 1.66 (June) to 4.88 (March), with an annual average of 3.16 ± 2.01. The secondary organic carbon (SOC) contributions, measured using the EC-tracer method, accounted for 45% of the total OC. The effective carbon ratio, which indicates an association between carbonaceous particles and climate change, ranged from 0.12 (July) to 0.74 (May). The study of air-mass origins revealed that days with air mass from E + NE registered the highest OC concentrations. This research provides new data on the variability of carbonaceous aerosols over the course of a year. It also highlights forest fires as a significant source of OC and EC, and indicates the high impact of SOC on OC concentration at the sampling site. [ABSTRACT FROM AUTHOR]

Observational black carbon (BC) data are needed at high resolution in vast areas to better study the climatic and environmental effect of BC aerosols. The BC concentration from Shanghai to Arctic Ocean was measured with an aethalometer (AE31) by the 7th Chinese National Arctic Research Expedition (CHINARE) during July to September 2016. A generally decreasing distribution of BC was shown from mid to high latitudes. The average BC concentration of the 7th CHINARE was higher than previous expeditions, at 22.77 ng m −3 in the Arctic Ocean. Moreover, we found heavy BC aerosols appearing occasionally during the CHINARE navigation. Therefore the impact of terrestrial transport was discussed based on the Arctic Transport Potential model. It was found that air pollution sources such as fires in the Arctic Circle of Eurasia could lead to BC transport to the high Arctic, inducing a high BC concentration of 95.62 ng m −3 . [ABSTRACT FROM AUTHOR]

Fine urban aerosol particles with aerodynamic equivalent dimeter ≤2.5 μm (PM 2.5 ) were collected in Mainz (a city within the Rhine-Main area, the third largest metropolitan region in Germany) and Beijing (Chinese megacity). A solvent mixture of acetonitrile-water was used to extract the organic aerosol fraction (OA) from the particle samples. The extracts were analyzed by an ultrahigh resolution mass spectrometer (UHRMS) Orbitrap coupled with ultra-high-performance liquid chromatography (UHPLC) both in the negative and positive ion mode. The number of compounds observed in Beijing is a factor of 2–10 higher compared to Mainz. The clear differences on chemical composition of OA in the two cities were observed. The majority of organics in Beijing OA is characterized by lower elemental H/C and O/C ratio but a higher degree of unsaturation and a larger aromaticity equivalent (X C ) compared to Mainz OA, suggesting that aromatics, which are related to direct combustion compounds (e.g., oxidized polycyclic aromatic hydrocarbon (PAH)), play an important role for OA in Beijing. A significant number of organosulfates (OSs) with long-carbon chain and low degree of unsaturation were observed in Beijing OA, indicating that long-chain alkanes emitted by vehicle might be their precursors. [ABSTRACT FROM AUTHOR]

Air pollution continues to be one of the main issues in urban areas. In addition to air quality plans and emission abatement policies, additional measures for high pollution episodes are needed to avoid exceedances of hourly limit values under unfavourable meteorological conditions such as the Madrid's short-term action NO 2 protocol. In December 2016 there was a strong atmospheric stability episode that turned out in generalized high NO 2 levels, causing the stage 3 of the NO 2 protocol to be triggered for the first time in Madrid (29th December). In addition to other traffic-related measures, this involves access restrictions to the city centre (50% to private cars). We simulated the episode with and without measures under a multi-scale modelling approach. A 1 km 2 resolution modelling system based on WRF-SMOKE-CMAQ was applied to assess city-wide effects while the Star-CCM+ (RANS CFD model) was used to investigate the effect at street level in a microscale domain in the city centre, focusing on Gran Vía Avenue. Changes in road traffic were simulated with the mesoscale VISUM model, incorporating real flux measurements during those days. The corresponding simulations suggest that the application of the protocol during this particular episode may have prevented concentrations to increase by 24 μg·m −3 (14% respect to the hypothetical no action scenario) downtown although it may have cause NO 2 to slightly increase in the city outskirts due to traffic redistribution. Speed limitation and parking restrictions alone (stages 1 and 2 respectively) have a very limited effect. The microscale simulation provides consistent results but shows an important variability at street level, with reduction above 100 μg·m −3 in some spots inside Gran Vía. Although further research is needed, these results point out the need to implement short-term action plans and to apply a consistent multi-scale modelling assessment to optimize urban air quality abatement strategies. [ABSTRACT FROM AUTHOR]

Background Epidemiologic studies of PM 2.5 (particulate matter with aerodynamic diameter ≤2.5 μm) and black carbon (BC) typically use ambient measurements as exposure proxies given that individual measurement is infeasible among large populations. Failure to account for variation in exposure will bias epidemiologic study results. The ability of ambient measurement as a proxy of exposure in regions with heavy pollution is untested. Objective We aimed to investigate effects of potential determinants and to estimate PM 2.5 and BC exposure by a modeling approach. Methods We collected 417 24 h personal PM 2.5 and 130 72 h personal BC measurements from a panel of 36 nonsmoking college students in Shanghai, China. Each participant underwent 4 rounds of three consecutive 24-h sampling sessions through December 2014 to July 2015. We applied backwards regression to construct mixed effect models incorporating all accessible variables of ambient pollution, climate and time-location information for exposure prediction. All models were evaluated by marginal R 2 and root mean square error (RMSE) from a leave-one-out-cross-validation (LOOCV) and a 10-fold cross-validation (10-fold CV). Results Personal PM 2.5 was 47.6% lower than ambient level, with mean (±Standard Deviation, SD) level of 39.9 (±32.1) μg/m 3 ; whereas personal BC (6.1 (±2.8) μg/m 3 ) was about one-fold higher than the corresponding ambient concentrations. Ambient levels were the most significant determinants of PM 2.5 and BC exposure. Meteorological and season indicators were also important predictors. Our final models predicted 75% of the variance in 24 h personal PM 2.5 and 72 h personal BC. LOOCV analysis showed an R 2 (RMSE) of 0.73 (0.40) for PM 2.5 and 0.66 (0.27) for BC. Ten-fold CV analysis showed a R 2 (RMSE) of 0.73 (0.41) for PM 2.5 and 0.68 (0.26) for BC. Conclusion We used readily accessible data and established intuitive models that can predict PM 2.5 and BC exposure. This modeling approach can be a feasible solution for PM exposure estimation in epidemiological studies. [ABSTRACT FROM AUTHOR]

Aerosol size distributions were measured using a scanning mobility particle sizer (SMPS), and also PM 1 (particulate matter ≤ 1 μm in aerodynamic diameter) samples were collected in parallel at a representative site in New Delhi during spring in 2013 and 2014. Based on the temporal variation of particle count mean diameter (CMD), sampling periods are characterized as growth events and non-growth events. Particle size distribution measurements suggest that some consecutive nights experienced unique nighttime subsequent growth of particles, which sustained for a longer period. Average particle growth rate measured during growth events was 5.64 ± 3.03 nm h −1 . Atmospheric trace gas concentrations and meteorological data show that these growth events (nighttime) are influenced by higher concentrations of gases, e.g., NO 2 (56.5 ± 29.7 μg m −3 ), SO 2 (9.34 ± 1.14 μg m −3 ) and RH (45.7 ± 9.5%) than those of non-growth events (daytime) (37.9 ± 18.6 μg m −3 , 7.19 ± 2.08 μg m −3 and 37.7 ± 6.9%, respectively). Further, analysis of PM 1 samples collected during the study period shows that the particulate water-soluble organic carbon (WSOC) (12.7 ± 4.1 μg m −3 ), NH 4 + (9.4 ± 3.2 μg m −3 ), SO 4 2− (2.03 ± 0.70 μg m −3 ), K + (1.06 ± 0.40 μg m −3 ), and NO 2 − + NO 3 − (0.59 ± 0.36 μg m −3 ) are the major contributors of particulate mass, wherein NH 4 + , SO 4 2− , K + , NO 2 − + NO 3 − mass concentrations were higher during growth events. Correlation study shows that nighttime aerosol composition during growth (in sub-micron range) events are more enriched by inorganic species (i.e., NH 4 NO 3 , (NH 4 ) 2 SO 4 and H 2 SO 4 vapors) as compared to organics (i.e., WSOC, does not show much difference in growth events and non events). Our results suggest that nighttime sulfate formation at the site is mostly mediated by high NO 2 and NH 3 at elevated RH. For the formation of sulfate and other inorganic species, a nighttime atmospheric chemistry is proposed, which is linked to particle growth. Growth events observed typically in nighttime have both biomass burning and anthropogenic influences as indicated by high concentrations of WSOC, K + and black carbon in PM 1 and carbon monoxide in gas phase. [ABSTRACT FROM AUTHOR]

The Stockholm Convention (SC) on Persistent Organic Pollutants (POPs) calls for the Parties' effectiveness evaluation of those measures taken to meet the reduction and eventual elimination of POPs from the environment. With that goal, air concentrations of different POP families have been measured uninterruptedly since 2008 under the Spanish Monitoring Program (SMP) by means of passive air sampling. This work focuses on data for polybrominated diphenyl ethers (PBDEs) determined in a total of 321 samples collected seasonally each year in 5 urban and 7 background sites. Neither significant temporal trends nor significant seasonal variations for total PBDE air burdens were detected. In contrast, significant variations were found among PBDE congeners. Those related to the octa-PBDE formulation significantly decreased in the study period. However, PBDEs related to the penta-formulation showed steady concentrations while PBDE-209, the congener found at the greatest levels, showed increasing or steady levels in most sampling sites. Seasonal variations were also markedly different among congeners. Concentrations of the lightest PBDEs (tri- to penta-substituted) were highly influenced by ambient temperature (T), showing maximum values in summer probably due to higher volatilization rates compared to those of heavier PBDEs. Contrarily, no clear seasonal trends were found for hexa- to deca-PBDEs, which were negatively related to precipitation; thereby, indicating an efficient atmospheric wash out by wet deposition episodes. Regarding spatial patterns, overall significant greater PBDE levels were found in cities compared to background areas, pointing out the role of highly populated areas as sources for these pollutants in Spain. Yet and especially in the case of PBDE-209, our results suggested the presence of significant unknown sources of PBDEs in some background sites. Further monitoring efforts are needed to assess potential unknown sources in the sampling network as well as to ensure temporal trends of these pollutants in Spain. [ABSTRACT FROM AUTHOR]

Industrial structures in China's resource-based cities are unlikely to materially change in the short term, and the large quantities of air pollutants emitted by residents' energy consumption cause serious air pollution. It is therefore urgently required to frame policies that can be adopted to realize the sustainable development of a social economy under the constraint of atmospheric environment in China's resource-based cities. In this paper, we develop a dynamic optimization model by using input–output analysis with gross regional product (GRP) maximization as the objective function. This model contains three submodels: the socioeconomic submodel, atmo-environmental control submodel, and energy submodel. The model is applied to Tangshan City, a typical resource-based industrial city, to conduct a dynamic simulation with 13 terms from 2013 to 2025 and based on the data in 2012. The goal for the model operation is to realize the optimal development of a social economy under the restrain of certain emission levels of air pollutants. This goal is achieved by introducing a comprehensive policy that includes a residential clean energy promotion policy and an industry emission reduction policy, and industrial restructuring also plays a role by industrial subsidies. The simulation results demonstrate that sulfur dioxide ( S O 2 ) and nitrogen oxides ( N O x ) can be reduced by 53% and 45%, respectively, in Tangshan City in 2025 compared with their values in 2012 with an annual GRP growth rate of 6.2%. The total output of the clean energy in the simulation period is 41.4 million tons of standard coal. The goal of improving the atmospheric environment and sustainable development of social economies in resource-based cities can be achieved by coordinating the relationship among economic development, atmospheric environmental protection, and energy consumption through a dynamic optimization model with a comprehensive policy and industrial restructuring. [ABSTRACT FROM AUTHOR]

Our study focuses on the carbon emission and mitigation potential in the domain of daily travel in Beijing. Using a sample with the focus on working class, the average individual carbon emissions from daily travel are computed as 1.46 kg/day•person and 2.40 kg/day•person for weekday and weekend. Except for residents who need to conduct more long-distance trips, the main contributor to the emissions of the rest high emitters are not the need of longer daily travel distances or the need to conduct more long distance trips, but the need to use cars more intensively for trips with similar distances compared with low emitters. High emitters are associated with the characteristics of being male, having higher income, owning cars, and being in the age between 30s and 40s. On the other hand, living within fifth ring and having good accessibility to public transport are associated with lower emissions. We innovatively use trip-based information to obtain a more relevant and realistic assessment of mitigation potential through mode shift under the current transport system. The mitigation percentage can be as high as 20%–25% if only travel time is considered, but will be substantially constrained by practical barriers. Therefore mitigation policy for daily transport should not only focus on improving travel time of low emission modes to comparable levels with cars but also tackle practical barriers for car drivers to use low emission modes. [ABSTRACT FROM AUTHOR]

Environmental noise is a growing concern for urban planners and public health experts. Continuous noise exposure has implications for people’s physical and mental health. Urban planning strategies are also involved in the need for regular noise assessments within urban areas. The objective of this study is to evaluate the exposure to noise of vulnerable population groups in the city of Barcelona, and to determine whether they are affected by an environmental inequity regarding this nuisance. Assessment of noise levels was performed by two methods of analysis—real measures and simulation—in order to build the noise database at block level for the 10 districts of the city. The results obtained by various statistical tests and spatial regression analysis show that children and low-income individuals are not affected by environmental inequity. On the other hand, we found a positive relationship between noise levels and the other groups considered: namely, the unemployed and people over age 65. [ABSTRACT FROM AUTHOR]

Traffic Related Air Pollution ( TRAP ) studies are usually investigated using different categories such as air pollution exposure for health impacts, urban transportation network design to mitigate pollution, environmental impacts of pollution, etc. All of these subfields often rely on a robust air pollution model, which also necessitates an accurate prediction of future pollutants. As is widely accepted by the heath authorities, TRAP is considered to be the major health issue in urban areas, and it is difficult to keep pollution at harmless levels if the time sequenced dynamic pollution and traffic parameters are not identified and modelled efficiently. In our work here, artificial intelligence techniques, such as Bayesian Networks with an optimized configuration, are used to deliver a probabilistic traffic data analysis and predictive modelling for air pollution (SO 2 , NO 2 and CO) at very local scale of an urban region with up to 85% accuracy. The main challenge for traditional data analysis is a lack of capability to reveal the hidden links between distant data attributes (e.g. pollution sources, dynamic traffic parameters, etc.), whereas some subtle effects of these parameters or events may play an important role in pollution on a long-term basis. This study focuses on the optimisation of Bayesian Networks to unveil hidden links and to increase the prediction accuracy of TRAP considering its further association with a predictive GIS system. [ABSTRACT FROM AUTHOR]

It is widely believed air pollution is an obstacle to cycling as it has negative effects on cyclists’ health outcomes and deteriorates their cycling experiences. However, the empirical studies investigating the impact of air pollution on cycling behaviour remains scarce. The aim of this paper is to fill the gap by looking at Beijing as a case study. The authors conducted a survey of 307 cyclists on the days with different levels of air quality in terms of concentration of PM 2.5 in 2015. The results show that in the polluted weather, those who persist in cycling are more likely to be male, over 30 years old, lower income or those who travel short distances. Specifically, female cyclists have a higher tendency to shift from cycling to public transit than the males and medium and high-income earners are more likely to shift to using a car than low income earners. The residents’ subjective perceptions of safety and comfort have major effects on their cycling behaviour. A higher perception of comfort and safety is related to a higher possibility of continuing cycling when air quality became polluted. Cycling for commuting trips is less likely to be replaced by other modes than cycling for non-commuting trips, such as shopping. Results of this study reveal that improving air quality in a metropolitan area such as Beijing has co-benefits of cycling renaissance. The huge investments into cycling infrastructure should be integrated with policies designed to create an attractive environment for cycling. [ABSTRACT FROM AUTHOR]

Since 2006, Beijing lowered its public transit fares as a way to improve air quality. However, Beijing increased public transportation fare prices from December 28, 2014, and commuters pay for the distance they traveled rather than a flat fare. This paper explores the effect of Beijing public transit fares increase on air quality. We collect daily data of air pollution and weather variables and use synthetic control method of Abadie and Gardeazabal (2003) to select control units. We then estimate a difference-in-differences model and assess the effect of the policy on air quality index (AQI). We find a 16.28% increase in air pollution in short run. However, we find no longer-run effect on air quality. [ABSTRACT FROM AUTHOR]

Studies on the natural human exposures to fine particulate matter (PM 2.5 ) and their elements composition are practically non-existent in South America. In order to understand the natural exposure of the typical Brazilian population to PM 2.5 and their trace element composition, we measured PM 2.5 concentrations and collected mass on filters for nine continuous hours during a typical workday of volunteers. In addition, bus routes were performed at peak and non-peak periods, mimicking the routine activity of the population. Mean concentrations of PM 2.5 in the bus and car groups were similar while the fraction of BCe was higher for the bus group. For all routes, mean PM 2.5 concentrations were higher during peak than non-peak hours, with an average of 43.5 ± 33.1 μg m −3 and 14.3 ± 10.2 μg m −3 , respectively. The trace elements S, K and Na originated mainly from vehicle emissions; Na was associated with the presence of biofuel in diesel. Toxic elements (Pb, Cr, Cu, Ni, Zn, Mn) were found at low levels as evident by the total hazard index that ranged from 2.15 × 10 −03 to 1.38 for volunteers. For all routes, the hazard index ranged from 2.25 × 10 −03 to 5.03. Average PM 2.5 respiratory deposition dose was estimated to be 0.60 μg/kg-hour for peak hours. Potential health damages to people during their movements and at workplaces close to the traffic were identified. Improvements in the design of the building to reduce the entrance of air pollutants as well as the use of filters in the buses could help to limit population exposure. [ABSTRACT FROM AUTHOR]

Background Although epidemiological studies have reported associations between mortality and both ambient air pollution and air temperature, it remains uncertain whether the mortality effects of air pollution are modified by temperature and vice versa. Moreover, little is known on the interactions between ultrafine particles (diameter ≤ 100 nm, UFP) and temperature. Objective We investigated whether the short-term associations of particle number concentration (PNC in the ultrafine range (≤100 nm) or total PNC ≤ 3000 nm, as a proxy for UFP), particulate matter ≤ 2.5 μm (PM 2.5 ) and ≤ 10 μm (PM 10 ), and ozone with daily total natural and cardiovascular mortality were modified by air temperature and whether air pollution levels affected the temperature-mortality associations in eight European urban areas during 1999–2013. Methods We first analyzed air temperature-stratified associations between air pollution and total natural (nonaccidental) and cardiovascular mortality as well as air pollution-stratified temperature-mortality associations using city-specific over-dispersed Poisson additive models with a distributed lag nonlinear temperature term in each city. All models were adjusted for long-term and seasonal trend, day of the week, influenza epidemics, and population dynamics due to summer vacation and holidays. City-specific effect estimates were then pooled using random-effects meta-analysis. Results Pooled associations between air pollutants and total and cardiovascular mortality were overall positive and generally stronger at high relatively compared to low air temperatures. For example, on days with high air temperatures (>75th percentile), an increase of 10,000 particles/cm 3 in PNC corresponded to a 2.51% (95% CI: 0.39%, 4.67%) increase in cardiovascular mortality, which was significantly higher than that on days with low air temperatures (<25th percentile) [−0.18% (95% CI: −0.97%, 0.62%)]. On days with high air pollution (>50th percentile), both heat- and cold-related mortality risks increased. Conclusion Our findings showed that high temperature could modify the effects of air pollution on daily mortality and high air pollution might enhance the air temperature effects. [ABSTRACT FROM AUTHOR]

Both climate change and intensive human activities are thought to have contributed to the impairment of atmospheric visibility in Beijing. But the detailed processes involved and relative roles of human activities and climate change have not been quantified. Optical extinction of aerosols, the inverse of meteorological visibility is especially sensitive to fine particles <1.0 μm. These submicron particles are considered more hazardous than larger ones in terms of cardiovascular and respiratory diseases. Here we used the aerosol optical extinction (inverse of visibility) as the indicator of submicron particles pollution to estimate its inter-annual variability from 1980 to 2015. Our results indicated that optical extinction experienced two different periods: a weakly increasing stage (1980–2005) and a rapidly increasing stage (2005–2015). We attributed the variations of optical extinction to the joint effects of human activities and climate change. Over the past 36 years, human activities played a leading role in the increase of optical extinction, with a positive contribution of 0.077 km −1 /10 y. While under the effects of climate change, optical extinction firstly decreased by 0.035 km −1 /10 y until 2005 and then increased by 0.087 km −1 /10 y. Detailed analysis revealed that the abrupt change (around 2005) of optical extinction resulted from the trend reversals of climate change. We found since 2005 the decreasing trend by 0.58 m·s −1 /10 y in wind speed, the growing trend at 8.69%/10 y in relative humidity and the declining trend by 2.72 hPa/10 y in atmospheric pressure have caused the rapid increase of optical extinction. In brief, the higher load of fine particles <1.0 μm in Beijing in recent decades could be associated with both human activities and climate change. Particularly after 2005, the adverse climate change aggravated the situation of submicron particles pollution. [ABSTRACT FROM AUTHOR]

In this study, the relationships between interannual variations of surface urban heat islands (SUHIs) and climate variability were studied in 31 cities of China for the period 2001–2016. For cold and dry Northern China, it was found that the interannual variations of SUHI intensity (SUHII, land surface temperature (LST) in urban minus rural) in urban cores was significantly ( p < 0.05) and negatively correlated with rural LST in 9 (in summer days (SDs)) and 8 (in winter days (WDs)) of the 15 northern cities, respectively. In addition, the daytime LST differences between hot summers and other summers and between cold winters and other winters were generally lower in urban cores (1.141 °C for SDs and 2.535 °C for WDs) than in rural areas (1.890 °C for SDs and 3.377 °C for WDs). The standard deviation was further used to reflect the interannual stabilities of LST, enhanced vegetation index (EVI) and white sky albedo (WSA). Interestingly, the standard deviations of LST across 2001–2016 were generally lower in urban cores (0.994 °C for SDs and 1.577 °C for WDs) than in rural areas (1.431 °C for SDs and 2.077 °C for WDs). Similar results were observed for EVI and WSA (winter). The results suggested that the urban surface is less sensitive to climate variability than rural areas in Northern China. Comparatively, most findings were less evident in hot and humid Southern China. Despite the whole world would become warmer or colder in future, the insensitivity of urban surface may mitigate its impacts in cold and dry Northern China. However, it does not mean that urbanization is totally good due to its environmental problem. [ABSTRACT FROM AUTHOR]

Droughts have historically had large impacts on agricultural production in rainfed agricultural systems. Scientists and policymakers have proposed various strategies for managing risks, with limited success. In this study we consider two such strategies, specifically drought tolerant rice and weather index insurance. While neither drought tolerant cultivars nor weather index insurance products are perfect solutions for adequately managing drought risk in and of themselves, there is scope to exploit the benefits of each and bundle them into a complementary risk management product, specifically through proper index calibration and an optimized insurance design. In this study, we explore preferences for such a complementary risk management product using discrete choice experiments in Odisha, India. We are able to estimate the added value that farmers perceive in the bundled product above and beyond the value associated with each of the independent products. We also show that valuations are very sensitive to the basis risk implied by the insurance product, with farmers less enthusiastic about risk management products that leave significant risks uninsured. [ABSTRACT FROM AUTHOR]

This paper argues that climate change adaptation through strategic greenspace planning requires scholars and planners to think differently about what equity means in an urban greenspace context. We use the heat mitigation potential of greenspace and the case of Taipei Metropolis in Taiwan to assess challenges arising from thinking about fairness in terms of distribution of benefits from greenspace functions, as opposed to fairness in greenspace accessibility and availability. Urban greening to foster ‘resilient’ communities arguably deflects from – or even exacerbates – structural causes of vulnerability, with benefits accruing disproportionately to more affluent or empowered groups. Yet the need for practical action on climate threats in cities is urgent, and for heat, strategic greenspace use considered systematically across a city may mitigate effects through the cooling effect of vegetation. The challenge is thus to balance the justice concerns associated with urban greening with this tangible risk reduction potential. We undertake content analysis of articles from two Taiwanese newspapers – the Taipei Times and the China Post – to assess how heat and greenspace issues have been discussed in urban governance debates within Taipei. We suggest change adaptation through urban greening raises three challenges for equity thinking: (a) guiding planning and governance processes with scientific understanding of how greenspace functions are delivered, even in the face of urban development pressures and site-specific controversies; (b) tempering the social cohesion and practical deployment benefits of neighbourhood-level greening with the need for specific understanding at the city-wide level to most effectively realise ecosystem services; and (c) linking targeted adaptation actions with broader rationales for urban greening, whilst not diluting justice concerns. We caution that pragmatism towards all urban climate adaptation via greening as intrinsically ‘good’ must not serve as a blinder to the need for accompanying social policy measures to reduce unequal vulnerability to climate risks. [ABSTRACT FROM AUTHOR]

The urgent need to develop low carbon urban transport systems particularly in Asian megacities is facing the significant challenge of growing motorization following population increase and economic development. Sustainable urban public transport (UPT) plays a crucial role to fulfil the ambitious targets on carbon emission reduction. In this study, life cycle assessment was employed to quantify the environmental impacts (measured by carbon emissions) of UPT systems (including bus and subway) in Shenzhen, a leading megacity in South China, and then to examine corresponding carbon intensity reduction potentials. Results showed that the total carbon emissions from UPT in Shenzhen have increased rapidly from 0.70 Mt in 2005 to 1.74 Mt in 2015 due to the fast growth of the volume of transport turnover. However, current low-carbon UPT mode has only reduced 0.21 Mt CO 2 e (cumulative value, from 2005 to 2015), and thus could not contribute proportionally to the city’s overall emission reduction target. Three advanced scenarios (from conservative to optimistic) were further simulated to estimate carbon emissions and their intensity reduction potentials over the next 15 years (2016–2030). Compared to the business-as-usual scenario, all these three low-carbon transition scenarios could significantly mitigate the rapid growth of carbon emissions and consequently help achieve Shenzhen’s carbon intensity reduction goal by 2030 (60%, compared to 2005 level). These findings could not only inform evidence-based policy making to facilitate the low-carbon transition of the urban transport sector in Shenzhen, but also shed light on sustainable urban transition in other megacities. [ABSTRACT FROM AUTHOR]

Quantifying the spatial pattern and change of urban greenspace is a prerequisite to understanding the myriad ecosystem services provided by urban greenspace. Previous studies have largely focused on loss of greenspace due to urban expansion, using medium resolution imagery. This paper presents a comparison study on the spatiotemporal patterns of urban greenspace in nine major cities in China, using 2.5 m resolution ALOS and SPOT image data collected in 2005 and 2010, respectively. The changes in urban greenspace were further compared with those based on the commonly used 30 m Landsat TM data. The results show: 1) Urban greenspace was highly fragmented and heterogeneous, characterized by a mix of a large number of small-sized patches (smaller than 0.1 ha) with relatively few dispersed large patches in nine cities. 2) In contrast to findings from previous research that greenspace in inner cities tends to remain largely unchanged, urban greenspace in all nine cities was highly dynamic, experiencing both gain and loss, with net change ranging from 0.51% to 11.26% over five years. Most of the changes in urban greenspace, however, tended to occur as small patches, and could only be revealed by high spatial resolution imagery. 3) Spatial patterns of greenspace varied greatly across cities in terms of patch size, patch and edge density, and shape. Urban greenspace became increasingly fragmented and complex in the southern cities, but the opposite in the northern cities. The high turnover dynamics of urban greenspace in cities proper provide opportunities for better design and planning to achieve urban sustainability, but also call for better protection of small-sized urban greenspaces in Chinese cities. [ABSTRACT FROM AUTHOR]

Atmospheric ammonia plays an important role in haze formation in East China. In this study, long-term measurements of NH 3 concentrations were implemented at urban, suburban, and tunnel sites in Shanghai, the largest city in East China. The average monthly ammonia concentrations at the urban site varied from 3.7 ppb to 14.5 ppb and exhibited the highest levels in summer and lowest levels in winter, indicating that the biological emissions and agriculture in the surrounding areas are important contributors. The suburban NH 3 levels were significantly higher in autumn compared to those at the urban site, indicating the important contribution of agricultural activities. Regardless of the season, the difference of NH 3 concentrations between the tunnel and urban sites remained almost constant. On average, the tunnel NH 3 level was three times higher than that of the nearby urban site, indicating strong vehicle NH 3 emissions in the tunnel. The tunnel NH 3 levels on weekdays were comparable to those on weekends, a result that was in agreement with the daily average traffic volume. It was estimated that the vehicle emissions contributed 12.6–24.6% of the atmospheric NH 3 in the urban area and 3.8–7.5% for the whole area of Shanghai. Our results suggest that vehicle NH 3 emissions should be considered, although agricultural emissions are still more important for mitigating severe haze pollution during wintertime in the megacities of China. [ABSTRACT FROM AUTHOR]

During summer monsoon season heavy to very heavy rainfall events have been occurring over most part of India, routinely result in flooding over Indian Monsoon Region (IMR). It is worthwhile to mention that as per Geological Survey of India, Odisha is one of the most flood prone regions of India. The present study analyses the occurrence of very light (0–2.4 mm/day), light (2.5 – 15.5 mm/day), moderate (15.6 – 64.4 mm/day), heavy (64.5 – 115.4 mm/day), very heavy (115.5 – 204.4 mm/day) and extreme (≥ 204.5 mm/day) rainy days over Odisha during summer monsoon season for a period of 113 years (1901 – 2013) and a detailed study has been done for heavy-to-extreme rainy days. For this purpose, India Meteorological Department (IMD) gridded (0.25° × 0.25° lat/lon) rainfall data and the European Centre for Medium-Range Weather Forecasts (ECMWF) Re-Analysis (ERA-Interim) (0.125° × 0.125° lat/lon) datasets are used. The analysis reveals that the frequency of very light, light and moderate rainy days persists with almost constant trend, but the heavy, very heavy and extreme rainy days exhibit an increasing trend during the study period. It may be noted that more than 60% of heavy-to-extreme rainy days are observed in the month of July and August. Furthermore, during the recent period (1980–2013), there are a total of 150 extreme rainy days are observed over Odisha, out of which 47% are associated with monsoon depressions (MDs) and cyclonic storms, 41% are with lows, 2% are due to the presence of middle and upper tropospheric cyclonic circulations, 1% is due to monsoon trough and other 9% of extreme rainy days does not follow any of these synoptic conditions. Since a large (nearly half) percentage of extreme rainy days over Odisha is due to the presence of MDs, a detailed examination of MDs is illustrated in this study. Analysis reveals that there are a total of 91 MDs formed over the Bay of Bengal (BoB) during 1980 – 2013, and out of which 56 (61.5% of total MD) MDs crossed Odisha. Further spatial analysis of extreme rainfall days exhibits that the maximum frequency of extreme rainy days is present over the south west region of Odisha. [ABSTRACT FROM AUTHOR]

Nowcasting short-duration (i.e., <6 h) rainfall (SDR) events is examined using total [i.e., cloud-to-ground (CG) and intra-cloud (IC)] lightning observations over the Beijing Metropolitan Region (BMR) during the warm seasons of 2006–2007. A total of 928 moderate and 554 intense SDR events, i.e., with the respective hourly rainfall rates (HRR) of 10–20 and ≥20 mm h −1 , are utilized to estimate sharp-increasing rates in rainfall and lightning flash, termed as rainfall and lightning jumps, respectively. By optimizing the parameters in a lightning jump and a rainfall jump algorithm, their different jump intensity grades are verified for the above two categories of SDR events. Then, their corresponding graded nowcast-warning models are developed for the moderate and intense SDR events, respectively, with a low-grade warning for hitting more SDR events and a high-grade warning for reducing false alarms. Any issued warning in the nowcast-warning models is designed to last for 2 h after the occurrence of a lightning jump. It is demonstrated that the low-grade warnings can have the probability of detection (POD) of 67.8% (87.0%) and the high-grade warnings have the false alarms ratio (FAR) of 27.0% (22.2%) for the moderate (intense) SDR events, with an averaged lead time of 36.7 (52.0) min. The nowcast-warning models are further validated using three typical heavy-rain-producing storms that are independent from those used to develop the models. Results show that the nowcast-warning models can provide encouraging early warnings for the associated SDR events from the regional to meso-γ scales, indicating that they have a great potential in being applied to the other regions where high-resolution total lightning observations are available. [ABSTRACT FROM AUTHOR]

This study focuses on the evolution through time of Tungurahua volcano (Ecuador), and provides new information regarding its history. Eighteen new K-Ar ages constrain its construction and the activity of its three successive edifices. We show that the volcano is much younger than expected. Indeed, the older edifice activity only began around 293 ± 10 ka, and ended at 79 ± 3 ka. After ~50 ka of quiescence, the second edifice started growing at 29 ± 2 ka after a major sector collapse, and itself collapsed at ~3 ka. Since then, the third edifice filled the amphitheatre and is still active. Together with numerical reconstructions of the morphology of the three edifices flanks before erosion, these new ages allow us to quantify the magmatic productivity rates during their construction, from 0.6 ± 0.3 and 0.9 ± 0.2 km 3 /ka for the two older edifices to 2.5 ± 1.0 km 3 /ka for the youngest, as well as an erosion rate of 0.2 ± 0.1 km 3 /ka, occurring since the end of Tungurahua I construction. Major and trace element contents of lavas from the three edifices display rather similar trends. Combined with our new ages, the magmatic signature through time does not seem to have been significantly affected either by the sector collapses experienced by the volcano, or by changes of the deep magmatic source. Finally, our results show that the K-Ar dating method by the unspiked Cassignol-Gillot technique performed on groundmass can be successfully applied to lava flows older than the Holocene, while the uncertainties related to younger units can prevent an accurate age determination. Particularly, this method can be applied to Quaternary volcanoes from the Ecuadorian arc, with many of them remaining without knowledge of the timing of their past activity. [ABSTRACT FROM AUTHOR]

Olive tree is one of the most important crop at global scale. Apulia is the first olive-producing region in Italy, with a huge amount of farms that generate Integrated Pest Management (IPM) data. IPM requires the simultaneous use of different crop protection techniques to control pests through an ecological and economic approach. The crop protection strategies are correlated to the climate condition considering the very important relation among climate, crops and pests. Therefore, in this work is presented a new advanced On-Line Analytical Processing (OLAP) model integrating the Growing Season Index (GSI), a phenology model, to compare indirectly the farms by a climatic point of view. The proposed system allows analysing IPM data of different farms having the same phenological conditions over a year to understand some best practices and to highlight and explain different practices adopted by farms working in different climatic conditions. [ABSTRACT FROM AUTHOR]

Chemical information is essential in understanding the characteristics of airborne particles, and effectively controlling airborne particulate matter pollution, but it remains unclear in some regions due to the scarcity of measurement data. In the present study, 92 daily PM 2.5 (particulate matter with an aerodynamic diameter ≤ 2.5 μm) samples as well as historical observation data of air pollutants were collected in urban Ningbo, one of important industrial cities in the coastal area of the Yangtze River Delta, China in autumn and winter (from Nov. 2014 to Feb. 2015). Various chemical species in PM 2.5 were determined including water soluble ions, organic and elemental carbon and elements. Positive matrix factorization model, cluster analysis of back trajectories, potential source contribution function (PSCF) model and concentration-weighted trajectory (CWT) model were used for identifying sources, apportioning contributions from each source and tracking potential areas of sources. The results showed the PM 2.5 concentration has been reducing; nonetheless, the concentrations of PM 2.5 are still much higher than the World Health Organization guideline with high PM 2.5 concentrations observed in autumn and winter for the past few years. During the sampling period, the average PM 2.5 mass concentration was 77 μg/m 3 with the major components of OC, NO 3 − , SO 4 2 − , NH 4 + and EC, accounting for 24.7, 18.8, 14.5, 11.8 and 6.4% in the total mass concentration, respectively. When the aerosol pollution got worse during the sampling period, the NO 3 − , SO 4 2 − and NH 4 + concentrations increased accordingly and NO 3 − appeared to increase at fastest rate. SO 4 2 − transported from industrial areas led to slight difference in spatial distribution of SO 4 2 − in Ningbo. More secondary organic carbon was formed and the enrichment factor values of Cu, Ag, Cd, Sn and Pb increased with the degradation of air quality. Ten types of sources were identified for PM 2.5 in the autumn and winter of Ningbo, which are metallurgical industry, biomass burning and waste incineration, manufacturing related with Mo, chlor-alkli chemical industry, oil combustion, vehicular emission, secondary source, soil dust, road dust and manufacturing related with Cr, accounting for 9.4, 4.8, 9.4, 7.6, 8.1, 18.7, 27.6, 2, 7.1 and 5.2% of the total sources, respectively. There were five groups of air parcels arriving in Ningbo, of which inland air masses originating from Shandong province were associated with the highest PM 2.5 concentrations. Despite the slight differences, it was obvious that the north of Jiangxi, east of Anhui, west of Jiangsu, south of Shandong were identified as major potential sources-areas of SO 4 2 − , NO 3 − , NH 4 + , Cl − , OC and EC by both PSCF and CWT models. [ABSTRACT FROM AUTHOR]

Partnerships emerge as part of an environmental governance paradigm shift towards less hierarchical, more collaborative, and non-regulative steering arrangements. This paper examines the prevalence of partnerships in environmental governance on an urban level in a semi-authoritarian setting, by exploring climate initiatives in cities in China. The paper presents exploratory qualitative analysis of governance in urban China through analysis of a database of 150 climate initiatives in 15 cities, which are seen at the forefront of climate protection. The analysis suggests that climate partnerships are used as a governance strategy in China. Moreover, partnerships perform a range of essential governance functions, from rule-setting and provision of public infrastructure and services, to supporting technology development and low carbon demonstration projects. The results indicate that partnerships can facilitate local climate action by creating access to resources, such as information, technology, and funding, as well as contribute to introduction of emission reduction technology and new policy approaches. However, the inclusion of non-state actors in the formulation and delivery of climate mitigation projects redefines the lines of authority over public issues. This draws attention to two key governance challenges in the context of a comparatively state-controlled, top-down political system: skewed participation and lack of deliberative opportunities. [ABSTRACT FROM AUTHOR]

It is increasingly recognised that meeting the obligations set out in the Paris Agreement on climate change will not be physically possible without deploying large-scale techniques for either removing greenhouse gases already in the atmosphere or reflecting sunlight away from the Earth. In this article we report on the findings of a scenarios method designed to interrogate how far these ‘climate engineering’ ideas may develop in the future and under what governance arrangements. Unlike previous studies in climate engineering foresight that have narrowly focussed on academic perspectives, a single climate engineering idea and a restricted range of issues, our approach sought to respond to theoretical imperatives for ‘broadening out’ and ‘opening up’ research methods applied to highly uncertain and ambiguous topics. We convened a one-day event with experts in climate change and climate engineering from across the sectors of government, industry, civil society and academia in the UK, with additional experts from Brazil, Germany and India. The participants were invited to develop scenarios for four climate engineering ideas: bioenergy with carbon capture and storage, direct air capture and storage, stratospheric aerosol injection and marine cloud brightening. Manifold challenges for future research were identified, placing the scenarios in sharp contrast with early portrayals of climate engineering research as threatening a ‘slippery slope’ of possible entrenchments, lock-ins and path dependencies that would inexorably lead to deployment. We suggest that the governance challenges for climate engineering should therefore today be thought of as less of a slippery slope than an ‘uphill struggle’ and that there is an increasingly apparent need for governance that responsibly incentivises, rather than constrains, research. We find that affecting market processes by introducing an effective global carbon price and direct government expenditure on research and development are incentives with broad potential applications to climate engineering. Responsibly incentivising research will involve a pluralistic architecture of governance arrangements and policy instruments that attends to collective ambitions as well as national differences and emerges from an inclusive and reflexive process. [ABSTRACT FROM AUTHOR]

Pedestrian-level wind environment in urban areas has a significant impact on the quality of urban dwellers' daily life. For pedestrian-level wind studies in severe cold regions, the cooling effect of wind and related thermal discomfort in winter is quite significant. However, thermal effects of wind are not considered in most wind comfort studies and wind comfort generally only refers to the mechanical effects of wind on people. Therefore, particular consideration is given to the chilling effect of wind on exposed skin and risk of frostbite in winter, and a wind chill criterion based on the wind chill temperature is proposed in this study. The pedestrian-level wind conditions in seven representative residential areas summarized from cities in severe cold regions of China are assessed based on the wind mechanical comfort criterion of NEN 8100 and the wind chill criterion. CFD simulations are performed to provide the pedestrian-level aerodynamic information, and the simulation results are validated by wind tunnel experiments. The assessment results show that the wind mechanical comfort or wind chill criterion need to be combined when assessing the wind conditions in severe cold regions. From the perspective of wind mechanical comfort and wind chill, the multi-storey residential areas with hybrid-type and the enclosed-type layout are recommended in severe cold regions. Moreover, a strict control of building height in residential areas is important to improve the pedestrian-level wind mechanical comfort, but not very helpful to reduce the occurrence of frostbite in winter. [ABSTRACT FROM AUTHOR]

This paper uses urban metabolism as a way to understand the sustainability of cities. It suggests that the city organism can reduce its metabolic footprint (resource inputs and waste outputs) whilst improving its livability. Like organisms, different cities have different metabolisms. This paper demonstrates that different parts of a city (walking, transit and automobile urban fabrics) also have different urban metabolisms. A detailed case study from the city of Perth, Australia, is used to demonstrate metabolic variations in different parts of the city. Understanding urban metabolism and the processes that drive it is the key to transitioning from ecologically extractive to sustainable cities. Through targeted improvements it is even possible for some elements of the city to become regenerative so that they restore parts of the degraded urban environment thus reversing damage to the biosphere. [ABSTRACT FROM AUTHOR]