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Summary Exposure to air pollution by burning solid fuels (such as coal) for residential cooking and heating in China has caused significant health impacts in the past. The government has implemented measures to replace coal with relatively clean energy sources (e.g., natural gas). However, the scale and scope of health benefits associated with such energy switching in an urban context, when considering both ambient and indoor air quality, remain unclear. Here we used an atmospheric chemical transport model showing that relatively clean energy use increased from 2% to 71% from 1980 to 2014, and although annual premature deaths attributed to particulate matter with an aerodynamic diameter less than 2.5 μm (PM2.5) from urban residential sources increased from 136,000 (87,000–194,000) to 202,000 (117,000–302,000) during the same period, this was primarily due to population growth, urbanization, aging, and background mortality rate changes. In the absence of energy switching, there would have been 2.2 million additional premature deaths. The results provide solid evidence on health benefits of energy switching, suggesting further switching to cleaner energy for expanded health-climate co-benefits.

Harmful SO2 largely originates from coal and oil combustions, but in some areas the biomass burning contribution could not be ignored. Here, we evaluated SO2 emissions from biomass burning (BB-SO2) with largely focusing on regional difference and temporal trends in the relative contributions of biomass burning from different sectors. Globally, the biomass burning emitted 4.26 (3.20–6.20) Tg SO2 in 2014, contributing 4.0% of the total SO2 emissions stemming from anthropogenic sources and natural open fires. But in some African and South Asian countries, biomass burning was a major source of SO2 with the contribution as high as 80–90%. Regarding sector contributions of biomass SO2, open fires contributed nearly half, followed by the residential sector (~29%) on the global scale, however, substantially different profiles were revealed across countries. Residential sector is the largest anthropogenic BB-SO2 source in the developing countries, while in the developed countries, industry and energy production were the two main anthropogenic BB-SO2sources. From 1960 to 2014, biomass SO2 emission, either the absolute amount or the relative contribution to the total, increased in the U.S. and Europe, and the contributions were over 20% in some countries. The biomass burning SO2 emission showed an increasing trend in India and a unimodal change in China, while a decreasing trend in the relative contributions were revealed in these two largest developing countries, which were 2.7% and 0.8%, respectively in 2014. With unignorable biomass burning contribution to SO2, as well as other hazardous air pollutants, in some regions, it is suggested that in assessing climate and health impacts of promoted biomass utilization when phasing out of fossil fuels, multiple components should be co-evaluated.

The imbalance of atmospheric, terrestrial and aquatic phosphorus budgets remains a research conundrum and global concern. In this work, the uptake, distribution, bioaccumulation and emission of organophosphate esters (OPEs) by clove trees (Syzygium aromaticum), lemon trees (Citrus limon) and cape jasmine trees (Gardenia jasminoides var. fortuniana) was investigated as conduits for phosphorus transfer or sinks and sources. The objective was to assess the role OPEs in soils play as atmospheric phosphorus sources through plant bioaccumulation and emission. Results demonstrated OPEs in experimental soil plots ranging from 0.01 to 81.0 ng g

Accurate estimation of black carbon (BC) emissions is essential for assessing the health and climate impact of this pollutant. Past emission inventories were associated with high uncertainty due to data limitations, and recent information has provided a unique updating opportunity. Moreover, understanding the drivers that cause temporal emission changes is of research value. Here, we update the global BC emission estimates using new data on the activities and emission factors (EFs). The new inventory covers 73 detailed sources at 0.1° × 0.1° spatial resolution and monthly temporal resolution from 1960 to 2017. The estimated annual emissions were 32% higher than the average of several previous inventories, which was primarily due to field-measured EFs for residential stoves and differentiated EFs for motor vehicles. In addition, the updated emissions show an inverse U-shaped temporal trend, which was mainly driven by the interaction between the positive effects of population growth, per capita energy consumption, and vehicle fleet and the negative effects of residential energy switching, stove upgrading, phasing out of beehive coke ovens, and reduced EFs for vehicles and industrial processes. Urbanization caused a significant increase in urban emissions accompanied by a more significant decline in rural emissions.

The residential sector is a major source of air pollutant emission inventory uncertainties. A nationwide field emission measurement campaign was conducted in rural China to evaluate the variabilities of realistic emission factors (EFs) from indoor solid fuel combustion. For a total of 1313 burning events, the overall average EFs (±standard deviation) of PM2.5 were 8.93 ± 6.95 and 7.33 ± 9.01 g/kg for biomass and coals, respectively, and 89.3 ± 51.2 and 114 ± 87 g/kg for CO. Higher EFs were found from burning of uncompressed straws, while lower EFs were found from processed biomass pellets, coal briquettes, and relatively clean anthracite coals. Modified combustion efficiency was found to be the most significant factor associated with variations in CO EFs, whereas for PM2.5, fuel and stove differences determined its variations. Weak correlations between PM2.5 and CO indicated high uncertainties in using CO as a surrogate for PM2.5. EFs accurately fit log-normal distributions, and obvious spatial heterogeneity was observed attributed to different fuel-stove combinations across the country. Emission estimation variabilities, which are determined by the interquartile ranges divided by the median values, were notably reduced when spatially resolved EFs were adopted in the inventory.

Conductive hydrogels with excellent electronic and mechanical properties are promising materials for flexible sensors. Herein we present a facile method to prepare reduced graphene oxide (rGO)-cont...

It remains challenging to develop hydrogels with comprehensive mechanical properties including ultrahigh strength, toughness and rapid self-recovery. Herein, dual physical crosslinking strategy was used to develop novel nanocomposite hydrogels reinforced by poly(N-vinylpyrrolidone) grafted cellulose nanocrystal (CNC-g-PVP). The hydrogels were fabricated via in situ copolymerization of acrylic acid (AA) and acrylamide (AM) in presence of CNC-g-PVP and subsequent introduction of Fe3+ ions. CNC-g-PVP induced the first crosslinking through strong cooperative hydrogen bonds existing between PVP chains grafted onto CNCs and amide groups from P(AM-co-AA) chains. Fe3+ triggered the second crosslinking by forming coordination bonds with –COO− groups. The cooperative hydrogen bonds enhanced the interfacial compatibility between CNC-g-PVP nanofillers and hydrogel matrix, and served as fast recoverable sacrificial bonds. As a result, the hydrogels exhibited high tensile strength (1.89–2.51 MPa), remarkable toughness (6.01–6.81 MJ/m3), rapid self-recovery (83.4–97.8% recovery of hysteresis loop within 5 min) and favourable fatigue resistance.

A nanofiber-directed templating strategy has been employed in this work to fabricate reticulated composites by decorating metal organic framework (MOF) onto a biomass scaffold of bacterial cellulose (BC). The abundant oxygen-containing groups on BC facilitate the highly dispersed nucleation of ZIF-8 (a typical MOF) and thus direct these nanocrystals assembly and growth along BC nanofibers homogeneously. The as-prepared ZIF-8@BC composites are converted into hierarchically porous carbon nanofibers with high intensity of N-dopants (N-PC@CBC) by a convenient carbonization process. In comparison with the bulk N-doping porous carbon (N-PC) by direct carbonization of pristine ZIF-8, N-PC@CBC exhibits more pronounced specific surface area and pore volume. As a result, N-PC@CBC shows outstanding oxygen reduction reaction catalytic performance approaching or even surpassing the commercial Pt/C catalyst. Additionally, the robust architecture of highly interweaved N-PC@CBC nanofibers as well as the sufficient N-dopants is also favorable for the enhancement of sodium-ion storage capability. After assembling the sodium-ion half-cells, the free-standing N-PC@CBC anodes display relatively high specific capacity, superior rate capability, and excellent cycling stability. The present work sheds light on a promising avenue to develop high-performance MOF-derived electrodes with cost-effective cellulose skeleton.

The hygroscopic behavior of black carbon (BC)-containing particles (BCPs) has a significant impact on global and regional climate change. However, the mechanism and factors controlling the hygroscopicity of BCPs from different carbon sources are not well understood. Here, we systematically measured the equilibrium and kinetics of water uptake by 15 different BCPs (10 herb-derived BCPs, 2 wood-derived BCPs, and 3 soot-type BCPs) using a gravimetric water vapor sorption method combined with in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). In the gravimetric analysis, the sorption–desorption equilibrium isotherms were measured under continuous-stepwise water vapor pressure conditions, while the kinetics was measured at a variety of humidity levels obtained by different saturated aqueous salt solutions. The equilibrium water uptake of the tested group of BCPs at high relative humidity (>80 %) positively correlated to the dissolved mineral content (0.01–13.0 wt %) (R2=0.86, P=0.0001), the content of the thermogravimetrically analyzed organic carbon (OCTGA, 4.48–15.25 wt %) (R2=0.52, P=0.002), and the content of the alkali-extracted organic carbon (OCAE, 0.14–8.39 wt %) (R2=0.80, P=0.0001). In contrast, no positive correlation was obtained with the content of total organic carbon or elemental carbon. Among the major soluble ionic constituents, chloride and ammonium were each correlated with the equilibrium water uptake at high relative humidity. Compared with the herbal BCPs and soot, the woody BCPs had much lower equilibrium water uptake, especially at high relative humidity, likely due to the very low dissolved mineral content and OC content. The DRIFTS analysis provided generally consistent results at low relative humidity. The kinetics of water uptake (measured by pseudo-second-order rate constant) correlated to the content of OCTGA and OCAE as well as the content of chloride and ammonium at low relative humidity (33 %) but to the porosity of BCPs at high relative humidity (94 %). This was the first study to show that BCPs of different types and sources had greatly varying hygroscopic properties.

Black carbon (BC) contributes to patterns of Arctic warming, yet the initial hydrophilic ratio (IHR) of BC emitted from various sources and its impact on Arctic BC remain uncertain. With the use of a tagged tracer method of BC implemented in the global chemistry transport model GEOS-Chem, IHRs were partitioned into 7 BC combustion source categories according to the PKU-BC-v2 emission inventory. The results show that as the IHR increased, the concentration of BC decreased globally. The impact on Arctic BC was mainly reflected in the vertical profile and the burden rather than at the surface. Specifically, the greatest impact of IHR on Arctic BC appeared in summer, with the largest perturbation appearing at an altitude of approximately 600 hPa, reaching 8%. This change in BC vertical profile was mainly caused by the IHR change of wildfire combustion in Russia (44%) and Canada (51%), and the emissions from these two regions were also the two most important contributors to the BC concentration and burden in the middle and lower Arctic atmosphere in summer. In the other three seasons, anthropogenic combustion sources (oil, coal, and biomass) in East Asia, Russia, and Europe accounted for 19-40%, 14-28%, and 7-23%, respectively, of the monthly BC burden. Emissions from Russia were the most important contributor (27-43%) to the monthly BC surface concentration. Due to the large adjustment in IHR from 20% to 70%, biomass burning in Europe was shown to be the dominant contributor causing both burden (39%) and surface concentration (88%) changes in all seasons except summer.

Polyacrylamide grafted cellulose nanocrystals (CNC-g-PAM) were incorporated into poly(vinyl alcohol) (PVA) by a solution casting method to fabricate nanocomposite films with enhanced therma...

Developing self-healable hydrogels with excellent mechanical performance is important for their potential applications. In this paper, tough and self-healable dual physically crosslinked nanocomposite hydrogels reinforced with polyacrylamide grafted cellulose nanocrystal (CNC-g-PAM) were fabricated by in situ free radical polymerization of acrylic acid (AA) monomers in the presence of FeCl3 (0.75% of AA mole) and CNC-g-PAM (1–3% of AA mass). The primary network of PAA/CNC-g-PAM nanocomposite hydrogels was constructed via coordination bonds between carboxylic groups from PAA and Fe3+ ions, while CNC-g-PAM served as both reinforcing nanofillers and physical crosslinkers via hydrogen bonds between PAA matrix and PAM chains on the surface of CNC. The nanocomposite hydrogels exhibited simultaneously improved elastic modulus, tensile strength and elongation at break with the increase of CNC-g-PAM loading. The dynamic nature of both coordination bonds and hydrogen bonds endowed the nanocomposite hydrogels with excellent energy dissipation, self-recovery ability and autonomous self-healing capacity.

Energy is vital to human society but significantly contributes to the deterioration of environmental quality and the global issue of climate change. Biomass and fossil fuels are important energy sources but have distinct pollutant emission characteristics during the burning process. This study aimed at attributing radiative forcing of climate forcers, including greenhouse gases but also short-lived climate pollutants, from the burning of fossil and biomass fuels, and the spatiotemporal characteristics. We found that air pollutant emissions from the burning process of biofuel and fossil fuels induced RFs of 68.2 ± 36.8 mW m

Atmospheric black carbon (BC) concentrations are governed by both emissions and meteorological conditions. Distinguishing these effects enables quantification of the effectiveness of emission mitigation actions by excluding meteorological effects. Here, we develop reduced-form models in both direct (RFDMs) and inverse (RFIMs) modes to estimate ambient BC concentrations. The models were developed based on outputs from multiyear simulations under three conditional scenarios with realistic or fixed emissions and meteorological conditions. We established a set of probabilistic functions (PFs) to quantify the meteorological influences. A significant two-way linear relationship between multiyear annual emissions and mean ambient BC concentrations was revealed at the grid cell scale. The correlation between them was more significant at grid cells with high emission densities. The concentrations and emissions at a given grid cell are also significantly correlated with emissions and concentrations of the surrounding areas, respectively, although to a lesser extent. These dependences are anisotropic depending on the prevailing winds and source regions. The meteorologically induced variation at the monthly scale was significantly higher than that at the annual scale. Of the major meteorological parameters, wind vectors, temperature, and relative humidity were found to most significantly affect variation in ambient BC concentrations.

Coal abatement actions for pollution reduction often target total coal consumption. The health impacts of coal uses, however, vary extensively among sectors. Here, we modeled the sectorial contributions of coal uses to emissions, outdoor and indoor PM2.5 (particulate matter with an aerodynamic diameter of less than 2.5 mm) concentrations, exposures, and health outcomes in China from 1970 to 2014. We show that in 2014, residential coal accounted for 2.9% of total energy use but 34% of premature deaths associated with PM2.5 exposure, showing that effects were magnified substantially along the causal path. The number of premature deaths attributed to unit coal consumption in the residential sector was 40 times higher than that in the power and industrial sectors. Emissions of primary PM2.5 were more important than secondary aerosol precursors in terms of health consequences, and indoor exposure accounted for 97% and 91% of total premature deaths attributable to PM2.5 from coal combustion in 1974 and 2014, respectively. Our assessment raises a critical challenge in the switching of residential coal uses to effectively mitigate PM2.5 exposure in the Chinese population.

International audience; Knowing the historical relative contribution of greenhouse gases (GHGs) and short-lived climate forcers (SLCFs) to global radiative forcing (RF) at the regional level can help understand how future GHGs emission reductions and associated or independent reductions in SLCFs will affect the ultimate purpose of the Paris Agreement. In this study, we use a compact Earth system model to quantify the global RF and attribute global RF to individual countries and regions. As our evaluation, the United States, the first 15 European Union members, and China are the top three contributors, accounting for 21.9 ± 3.1%, 13.7 ± 1.6%, and 8.6 ± 7.0% of global RF in 2014, respectively. We also find a contrast between developed countries where GHGs dominate the RF and developing countries where SLCFs including aerosols and ozone are more dominant. In developing countries, negative RF caused by aerosols largely masks the positive RF from GHGs. As developing countries take measures to improve the air quality, their negative contributions from aerosols will likely be reduced in the future, which will in turn enhance global warming. This underlines the importance of reducing GHG emissions in parallel to avoid any detrimental consequences from air quality policies.

Satellite data and models suggest that oceanic productivity is reduced in response to less nutrient supply under warming. In contrast, anthropogenic aerosols provide nutrients and exert a fertilizing effect, but its contribution to evolution of oceanic productivity is unknown. We simulate the response of oceanic biogeochemistry to anthropogenic aerosols deposition under varying climate from 1850 to 2010. We find a positive response of observed chlorophyll to deposition of anthropogenic aerosols. Our results suggest that anthropogenic aerosols reduce the sensitivity of oceanic productivity to warming from −15.2 ± 1.8 to −13.3 ± 1.6 Pg C yr−1 °C−1 in global stratified oceans during 1948–2007. The reducing percentage over the North Atlantic, North Pacific, and Indian Oceans reaches 40, 24, and 25%, respectively. We hypothesize that inevitable reduction of aerosol emissions in response to higher air quality standards in the future might accelerate the decline of oceanic productivity per unit warming., Key Points Anthropogenic aerosol deposition alleviates the nutrient limitation in the oceansResponse of observed chlorophyll to anthropogenic aerosol deposition is modeledOver 1948–2007, the sensitivity of oceanic productivity to warming is reduced by 12.5%

The Research to Practice Full Paper focuses on the professional code of ethics which sets a standard for which each member of the profession can be expected to meet. It is a promise to act in a manner that protects the public's well-being. In the workplace, if we use shoddy materials or workmanship on the job, we can jeopardize the safety of others. Therefore, it is essential that all students shall fully understand the professional and ethical responsibility before they graduate for career development.Unfortunately, there is a consistent lack of data measuring students’ capabilities to understand their professional ethics due to the unmeasurable nature of moral reasoning. To address this issue and equip faculty with more tools to enhance students’ comprehension of ethical engineering practice, the present research proposes a quantitative approach to measuring ethical behavior and exploring its contributing factors based on a somewhat long duration (years 2013-2019) of senior exit survey data consisting of more than 1000 survey responses. The senior exit survey questionnaire is made up of a set of questions to gauge the students' self-rated capabilities of student outcomes (e.g., ethical responsibility, communication skills, life-long learning, etc.), collect background information (e.g., admission year, transfer or first-time freshman, etc.) and quantity the level of extracurricular participation (e.g., number of student clubs participated, the amount of engagement for part-time work, etc.).There is a broad range of statistical tools to deal with the multiple categorical responses (1- Poor; 2 – Fair; 3 – Average; 4– Good; 5 – Excellent) to the understanding of professional ethics as implemented in the survey, which includes nominal, ordinal, logit, and probit, and so on. Given the strengths and weaknesses associated with various modeling techniques, the study uses different combinations containing multinomial logit, ordinal logit, and ordinal probit. The multiple combinations are employed for two reasons: First, the comparison of these models is rarely conducted based on the educational data. Second, the common results identified from the different models would lead to reliable findings with more confidence. Distinct data preparation tasks such as data-centering, scaling, outlier identification, and covariate correlation analysis, were used prior to modeling development to ensure result accuracy. The findings illustrate various statically influential factors to enhance students’ professional ethics and therefore shed more insight into faculty who aims at improving student outcomes especially from the fact of ethics and morals.

Introduction: Pedestrian safety is a major concern as traffic crashes are the leading cause of fatalities and injuries for commuters. Traffic safety research in the past has developed various strategies to counteract traffic crashes, including the safety performance function (SPF). However, there is still a need for research dedicated to enhancing the SPF for pedestrians from perspectives of methodological framework and data input. To fill this gap, this study aims to add to the current SPF development practice literature by focusing on pedestrian-involved collisions, while considering the typical vehicle ones as well. Methods: First, bivariate models are used to account for the common unobserved heterogeneity shared by the pedestrian- and vehicle-related crashes at the same intersections. Second, variable importance ranking technique is used, along with correlation analysis, to determine mode-specific feature input. Third, the exposure information for both modes, annual pedestrian count, and annual daily vehicles traveled are used for model development. Fourth, a recent Bayesian inference approach (integrated nested Laplace approximation (INLA)) was adopted for bivariate setting. Finally, different evaluation criteria are used to facilitate comprehensive model assessment. Results: The results reveal different statistically significant factors contributing to each of the modes. The offset intersection provides better safety performance for both pedestrians and drivers as compared to other intersection designs. The model findings also corroborate the sensibility of using the bivariate models, rather than the separate univariate ones. Practical Applications: The study shows that pedestrians are more vulnerable to various intersection features such as left-turn channelization, intersection control, urban and rural population group, presence of signal mastarm on the cross-street, and mainline average daily traffic. Greater focus should be directed toward such intersection features to improve pedestrian safety.

We tracked atmospheric phosphorus (P) in suspended particulate matter (PM) from a site in Beijing, China over a three-year period and found a new relationship between plants and atmospheric P. Concentrations of total phosphorus (TP) in the atmosphere during plant growing seasons were 2.5 times those observed in other months and levels of organic phosphorus (OP) were 3.9 times as high. TP and OP increases during growing seasons were much more significant in PM with diameters of over 2.5 μm (PM>2.5). PM collected during growing seasons included high levels of P but less nitrogen than that in primary biogenic aerosol particles (PBAPs) and differed from other emission sources such as combustion emissions and dust. A time series of OP concentrations in the atmosphere shows a time lag relative to Normalized Difference Vegetation Index (NDVI) data with high levels found during early growing periods and much lower levels found during flourishing periods. Thus, we find that plants contribute to atmospheric P and especially to OP rather than to PBAP levels.

Rice yield have been affected by the increased extreme precipitation events in recent decades. Yet, the spatio-temporal patterns of extreme precipitation by rice type and phenology remain elusive. Here, we investigate the characteristics of four extreme precipitation indices across China’s rice paddy and their potential association with crop yields, by using hourly precipitation data from 1,215 stations and rice phenology observations from 45 sub-regions. The data indicate that hourly extreme precipitation have significantly increased in 1961–2012 for single rice and early rice in China but not for late rice. Rice were mainly exposed to extreme precipitation from transplantation to flowering stages. The frequency and proportion of extreme precipitation were significantly increased by 2.0–4.7% and 2.3–2.9% per decade, respectively, mainly in south China and Yangtze River Basin. The precipitation intensity and maximum hourly precipitation were increased by 0.7–1.1% and 0.9–2.8% per decade, respectively, mainly in central China and southeast coastal area. These extreme precipitation indices played a role as important as accumulated precipitation and mean temperature on the interannual variability of rice yields, regardless of rice types. Our results also highlight the urgencies to uncover the underlying mechanisms of extreme precipitation on rice growth, which in turn strengthens the predictability of crop models.

International audience; The emission and deposition of global atmospheric phosphorus (P) have long been considered unbalanced, and primary biogenic aerosol particles (PBAP) and phosphine (PH3) are considered to be the only atmospheric P sources from the ecosystem. In this work, we found and quantified volatile organic phosphorus (VOP) emissions from plants unaccounted for in previous studies. In a greenhouse in which lemons were cultivated, the atmospheric total phosphorus (TP) concentration of particulate matter (PM) was 41.8% higher than that in a greenhouse containing only soil, and the proportion of organic phosphorus (OP) in TP was doubled. 31P nuclear magnetic resonance tests (31P-NMR) of PM showed that phosphate monoesters were the main components contributed by plants in both the greenhouse and at an outside observation site. Atmospheric gaseous P was directly measured to be 1–2 orders of magnitude lower than P in PM but appeared to double during plant growing seasons relative to other months. Bag-sampling and gas chromatography mass spectrometry (GCMS) tests showed that the gaseous P emitted by plants in the greenhouse was triethyl phosphate. VOP might be an important component of atmospheric P that has been underestimated in previous studies.

The hygroscopic behavior of black carbon (BC) has a significant impact on global and regional climate change. However, the mechanism and factors controlling the hygroscopicity of BC from different carbon sources are not well understood. Here, we systematically measured the equilibrium and kinetics of water uptake by 15 different BC (10 herb-derived BC, 2 wood-derived BC, and 3 soot) using gravimetric water vapor sorption method combined with in-situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). In the gravimetric analysis, the sorption/desorption equilibrium isotherms were measured under continuous-stepwise water vapor pressure conditions, while the kinetics was measured at a variety of humidity levels obtained by different saturated aqueous salt solutions. The equilibrium water uptake of the BC pool at high relative humidity (> 80 %) positively correlated to the dissolved mineral content (0.01–13.0 wt %) (R2 = 0.86, P = 0.0001) as well as the content of the thermogravimetrically analyzed organic carbon (OCTGA, 4.48–15.25 wt %) (R2 = 0.52, P = 0.002) and the alkali-extracted organic carbon (OCAE, 0.14–8.39 wt %) (R2 = 0.80, P = 0.0001). In contrast, no positive correlation was obtained with the content of total organic carbon or elemental carbon. Among the major soluble ionic constituents, chloride and ammonium were each correlated with the equilibrium water uptake at high relative humidity. Compared with the herbal BC and soot, the woody BC had much lower equilibrium water uptake, especially at high relative humidity, likely due to the very low dissolved material content and OC content. The DRIFTS analysis provided generally consistent results at low relative humidity. The kinetics of water uptake (measured by pseudo-second order rate constant) correlated to the content of OCTGA and OCAE as well as the content of chloride and ammonium at low relative humidity (33 %), but to the porosity of bulk BC at high relative humidity (94 %). This was the first study to show that BC of different types and sources has greatly varying hygroscopic properties.

We present a facile strategy for the fabrication of mechanically tough and self-recoverable nanocomposite hydrogels reinforced by surface-modified cellulose nanocrystals. Polyacrylamide grafted cellulose nanocrystal (CNC-g-PAM) was first synthesized by ceric salt initiated surface graft polymerization of acrylamide onto CNC, then incorporated into chemically crosslinked poly(acrylic acid) (PAA) networks to obtain dual-crosslinked CNC-g-PAM/PAA nanocomposite hydrogels. CNC-g-PAM acted as both interfacial compatible nanofillers and physical crosslinkers through reversible hydrogen bonds between PAA and PAM on the surface of CNC. FTIR analysis confirmed the formation of above hydrogen bonds. Scanning electron microscopy observations revealed good interfacial compatibility between CNC and PAA matrix. The nanocomposite hydrogels exhibited decreasing swelling ratio with increasing CNC-g-PAM content. Uniaxial tensile tests and tensile loading-unloading tests showed that elastic modulus, breaking strength and elongation at break of the nanocomposite hydrogels were significantly increased compared to PAA hydrogel, and that the nanocomposite hydrogels exhibited good self-recovery ability after large deformation.

International audience; Precipitation is one of the most important factors determining the occurrence of extreme hydro-meteorological events and water resource availability. Precipitation in different grades has diverse ecological effects, and slight precipitation (SP, defined as 0.1-1.0 mm/day) is the minimal level among them. In this study, we investigated SP trends from 1961 to 2013, as well as the relationship between SP and advanced very high radiometric resolution (AVHRR) normalized difference vegetation index (NDVI) in China during growing season from 1981 to 2006. The distributions and trends of SP were analysed by calculating the daily precipitation data. The average annual slight precipitation amount (SPA) and the number of slight precipitation days (SPD), derived from 839 monitoring stations in China, show a decreasing trend over the last five decades, which is in agreement with total precipitation (TP) but in different rates. When the trend was analysed seasonally, SP in most stations decreases significantly in September-October-November (SON) and June-July-August (JJA), and the largest decrease is found in SON. About 49.5 and 68.7% of monitoring stations show a decreasing trend in SON, in both SPA and SPD, whereas the trend is less popular in March-April-May Accepted manuscript. Li et al. 2018, International Journal of Climatology. https://doi.org/10.1002/joc.5763 page 2 (MAM, SPA: 19.7%, SPD: 41.4%) and December-January-February (JJF, SPA: 25.6%, SPD: 43.1%). Moreover, our analysis indicates that the decrease of SP is mainly due to the decrease of SPD as the median amount of daily SP was unchanged over the past five decades (close to 0.3 mm/day). Based on 26-year (1981-2006) semi-monthly AVHRR NDVI data and the records of SP data, the relationship between AVHRR NDVI and SP was also investigated. In regions with lower (

Facilitated transport cellulose membranes with different zinc ion loadings are fabricated via a facile and green solvent system (zinc chloride/calcium chloride solution). Zn2+ ions lower the pristine hydrogen bonds that normally reinforce the cellulose chains, and Ca2+ ions facilitate interactions among the Zn–cellulose chains to form nanofibrils. The strategy provides an effective route to immobilize zinc species into membrane matrix and constructs facilitated transport pathway for CO2 molecules. The self-standing membranes are transparent, flexible and demonstrate ultraselective CO2 permeation. The optimum separation performance is achieved over CM-0 with the highest zinc content (22.2%), and it exhibits a CO2 permeability of 155.0 Barrer, with selectivity ratios of 27.2 (CO2/N2) and 100.6 (CO2/O2). The excellent separation performance is assigned to the π complexation mechanism between Zn2+ and CO2.

Rural household energy use for cooking and heating is an important source of air pollutants in China, as it affects both human health and climate change. However, the magnitude of rural household energy use, especially during the recent rapid socioeconomic transition period, has not been well quantified. Here, we present first-hand nationwide data from a 34,489-household energy-mix survey and a 1,670-household fuel-weighing campaign. We found that the consumption of wood and crop residues in rural China decreased by 63% and 51%, respectively, from 1992 to 2012, and these decreases were much greater than the 15% and 8%, respectively, reported by the International Energy Agency and Food and Agriculture Organization. The rapid residential energy transition over these two decades was primarily driven by the rapid socioeconomic development. One important implication of this transition is the significant reduction in the emissions of major air pollutants, especially incomplete combustion products leading to significant impacts on health and climate. Use of wood and crop residue for cooking and heating in rural China is a significant source of carbon emissions and air pollution. Using a survey of more than 34,000 households, researchers show that between 1992 and 2012 usage of these fuels decreased by much more than previous estimates, due primarily to rising incomes.

Significance At present, many environmental laws and regulations are enforced in China, but they are often not well evaluated for their performance. In this study, the health effects of beehive coke oven operations, the ban of the ovens, and the slow implementation of the ban were assessed quantitatively, showing the importance of not only the legislation but also the implementation of the law. This study provides a good example that shows how environmental legislation and implementation can be evaluated to scientifically support decision making., Environmental legislation and proper implementation are critical in environmental protection. In the past, beehive coke ovens (BCOs) were popular in China, resulting in enormous emissions of benzo[a]pyrene (BaP), a common indicator of carcinogenic polycyclic aromatic hydrocarbons. BCOs were banned by the Coal Law in 1996. Although BCO numbers have declined since the ban, they were not eliminated until 2011 due to poor implementation. Here, we present the results of a quantitative evaluation of the health effects of historical BCO operation, the health benefits of the ban, and the adverse impacts of the poor implementation of the ban. With only limited official statistics available, historical and geospatial data about BCOs were reconstructed based on satellite images. Emission inventories of BaP from BCOs were compiled and used to model atmospheric transport, nonoccupational population exposure, and induced lung cancer risk. We demonstrated that more than 20% of the BaP in ambient air was from BCOs in the peak year. The cumulative nonoccupational excess lung cancer cases associated with BaP from BCOs was 3,500 (±1,500) from 1982 to 2015. If there was no ban, the cases would be as high as 9,290 (±4,300), indicating the significant health benefits of the Coal Law. On the other hand, if the ban had been fully implemented immediately after the law was enforced in 1996, the cumulative cases would be 1,500 (±620), showing the importance of implementing the law.

Supramolecular polyurea (PU) hydrogels with combined anti-swelling capacity, thermochromic properties, and tunable water content and mechanical performance were obtained by immersing phase separated PU films with hydrophilic soft segments in water till swelling equilibrium. The multiple H-bonds within hard-segment domains are critical to the swelling and mechanical properties, which were rationally designed by using simultaneously two aliphatic diisocyanates with different symmetry and varying molar ratio. Consequently, the hydrogels exhibit a wide range of equilibrium water content (57–80%), elastic modulus (22–476 kPa), breaking strength (33–1720 kPa), and elongation at break (160–1460%). The hydrogels also exhibit fast recovery during cyclic loading-unloading. The incorporation of strong quadruple H-bonds into hard-segment domains endowed the hydrogels with stable anti-swelling capacity. Additionally, the hydrogels changed from transparent to opaque reversibly upon heating and cooling, originating from the phase transition of soft segments. The developed supramolecular PU hydrogels show promising potentials in many fields like smart windows.

A two-step method was used to fabricate a superhydrophobic surface on steel sheet, nickel foam (NF), and stainless steel mesh (SS). The micro-nano structure of Layer Double Hydroxide (LDH) is obtained by hydrothermal method. The synergistic effect of triethoxy(octyl)silane (TTOS) and FeNi-LDH produces a superhydrophobic surface. Fourier infrared spectroscopy (FTIR), X-ray diffractometer (XRD), X-ray photoelectron spectroscopy (XPS), and scanning electron microscope (SEM) were used for structural characterization, which confirmed the synthesis and hydrophobic modification of FeNi-LDH. The time of the hydrothermal reaction was discussed, and the results showed that the water contact angle (WCA) of the superhydrophobic surface fabricated by setting the reaction time to 12 h can reach 169 ± 2°. Electrochemical tests also show that the prepared superhydrophobic surface can achieve a corrosion inhibition rate of 96.3%. In addition, the superhydrophobic NF and superhydrophobic SS prepared by the same method were tested for antifouling and oil-water separation performance. The results show that, due to the excellent non-wettability of the surface, the preparation method of this superhydrophobic surface has great potential value in the fields of anti-corrosion, anti-fouling and oil-water separation.

Polycyclic aromatic hydrocarbons (PAHs) derivatives like nitrated and oxygenated PAHs (nitro- and oxy-PAHs) are of growing interests due to their direct and potentially high toxic properties. PAHs derivatives can be produced from primary sources and also can derive from photochemical reactions, however, works about the quantitative contributions of primary and secondary sources are scarce. In this study, levels and seasonal distributions of ambient nitro- and oxy-PAHs were studied in a megacity Nanjing located in East China and evaluated for relative contributions of different sources. The annual average concentrations of most PAH derivatives were generally lower than the levels found in north China, but higher than the levels reported for south China. The relative contributions of secondary formation ranged from 10% to 47% for nitro-PAHs and ∼60% for oxy-PAHs. The study suggested that typical source apportionment technologies could be adopted to investigate primary and secondary sources of PAHs derivatives when derivatives are simultaneously measured with parent PAHs and other source markers. Future studies are interesting to develop, evaluate and compare different source apportionment methodologies for PAHs derivatives.

Sixteen U.S. EPA priority polycyclic aromatic hydrocarbons (PAHs) and eleven non-priority isomers including some dibenzopyrenes were analyzed to evaluate health risk attributable to inhalation exposure to ambient PAHs and contributions of the non-priority PAHs in a megacity Nanjing, east China. The annual average mass concentration of the total 16 EPA priority PAHs in air was 51.1 ± 29.8 ng/m3, comprising up to 93% of the mass concentration of all 27 PAHs, however, the estimated Incremental Lifetime Cancer Risk (ILCR) due to inhalation exposure would be underestimated by 63% on average if only accounting the 16 EPA priority PAHs. The risk would be underestimated by 13% if only particulate PAHs were considered, though gaseous PAHs made up to about 70% of the total mass concentration. During the last fifteen years, ambient Benzo[a]pyrene decreased significantly in the city which was consistent with the declining trend of PAHs emissions. Source contributions to the estimated ILCR were much different from the contributions for the total mass concentration, calling for the introduce of important source-oriented risk assessments. Emissions from gasoline vehicles contributed to 12% of the total mass concentration of 27 PAHs analyzed, but regarding relative contributions to the overall health risk, gasoline vehicle emissions contributed 45% of the calculated ILCR. Dibenzopyrenes were a group of non-priority isomers largely contributing to the calculated ILCR, and vehicle emissions were probably important sources of these high molecular weight isomers. Ambient dibenzo[a,l]pyrene positively correlated with the priority PAH Benzo[g,h,i]perylene. The study indicates that inclusion of non-priority PAHs could be valuable for both PAH source apportionment and health risk assessment.

Residential contributions are substantially magnified from energy use, emissions, air pollution, to health impacts., Residential contribution to air pollution–associated health impacts is critical, but inadequately addressed because of data gaps. Here, we fully model the effects of residential energy use on emissions, outdoor and indoor PM2.5 concentrations, exposure, and premature deaths using updated energy data. We show that the residential sector contributed only 7.5% of total energy consumption but contributed 27% of primary PM2.5 emissions; 23 and 71% of the outdoor and indoor PM2.5 concentrations, respectively; 68% of PM2.5 exposure; and 67% of PM2.5-induced premature deaths in 2014 in China, with a progressive order of magnitude increase from sources to receptors. Biomass fuels and coal provided similar contributions to health impacts. These findings are particularly true for rural populations, which contribute more to emissions and face higher premature death risks than urban populations. The impacts of both residential and nonresidential emissions are interconnected, and efforts are necessary to simultaneously mitigate both emission types.