Understanding the effectiveness of national air pollution controls is important for control policy design to improve the future air quality in China. This study evaluated the effectiveness of major national control po...Understanding the effectiveness of national air pollution controls is important for control policy design to improve the future air quality in China. This study evaluated the effectiveness of major national control policies implemented recently in China through a modeling analysis. The sulfur dioxide （SO2） control policy during the llth Five Year Plan period （2006-2010） had succeeded in reducing the national SO2 emission in 2010 by 14% from its 2005 level, which correspondingly reduced ambient SO2 and sulfate （SO42-） concentrations by 13%-15% and 8%-10% respectively over east China. The nitrogen oxides （NOx） control policy during the 12th Five Year Plan period （2011-2015） targets the reduction of the national NOx emission in 2015 by 10% on the basis of 2010. The simulation results suggest that such a reduction in NOx emission will reduce the ambient nitrogen dioxide （NO2）, nitrate （NO3-）, 1-hr maxima ozone （03） concentrations and total nitrogen deposition by 8%, 3%-14%, 2% and 2%--4%, respectively over east China. The application of new emission standards for power plants will further reduce the NO2, NO3-, 1-hr maxima 03 concentrations and total nitrogen deposition by 2%-4%, 1%-%, 0-2% and 1%-2%, respectively. Sensitivity analysis was conducted to evaluate the inter-provincial impacts of emission reduction in Beijing-Tianjin-Hebei and the Yangtze River Delta, which indicated the need to implement joint regional air pollution control.展开更多
Gamma irradiation mutagenesis is a technique commonly used to induce seedlessness in citrus fruits. We compared fruit quality traits of eight different seeded mandarin varieties within the Israeli citrus breeding coll...Gamma irradiation mutagenesis is a technique commonly used to induce seedlessness in citrus fruits. We compared fruit quality traits of eight different seeded mandarin varieties within the Israeli citrus breeding collection with those of their corresponding gamma-irradiated low-seeded mutants. The mandarin varieties compared were: “Rishon” with “Kedem”;“Michal” with irradiated “Michal”;“Merav” with “Meravit”;“Vered” with “Vardit”;“Ora” with “Or”;“Murcott” with “Mor”;“Shani” with irradiated “Shani”;“King” with irradiated “King”. Mutational breeding by gamma irradiation reduced average fruit seed number by 70% - 92%. Furthermore, mutational breeding by gamma irradiation delayed ripening of the early-season mandarin varieties “Rishon” and “Michal” by 8 - 13 days, but did not delay ripening of most mid- and late-season varieties. Gamma-irradia- tion mutagenesis also reduced fruit weight of seven of the eight tested low-seeded varieties by 6 - 41 g per fruit. Gamma-irradiation mutagenesis had variable effects on biochemical composition and nutritional quality, in that some irradiated clones presented no changes whereas other had either higher or lower levels of juice total soluble solids, acidity, vitamin C and total antioxidant activity. Finally, sensory evaluations by a trained panel revealed that the flavor of most of the low-seeded, gamma-irradiated varieties was slightly or significantly preferable to that of unirradiated varieties.展开更多
The national Air Pollution Prevention and Control Action Plan required significant decreases in PM_（2.5） levels over China.To explore more effective emission abatement strategies in industrial cities,a case study wa...The national Air Pollution Prevention and Control Action Plan required significant decreases in PM_（2.5） levels over China.To explore more effective emission abatement strategies in industrial cities,a case study was conducted in Baotou to evaluate the current national control measures.The total emissions of SO_2,NO_X,PM_（2.5） and NMVOC（non-methane volatile organic compounds） in Baotou were 211.2 Gg,156.1 Gg,28.8 Gg,and 48.5 Gg,respectively in 2013,and they would experience a reduction of 30.4%,26.6%,15.1%,and 8.7%,respectively in 2017 and 39.0%,32.0%,24.4%,and 12.9%,respectively in2020.The SO_2,NO_Xand PM_（2.5） emissions from the industrial sector would experience a greater decrease,with reductions of 37%,32.7 and 24.3%,respectively.From 2013 to 2020,the concentrations of SO_2,NO_2,and PM_（2.5） are expected to decline by approximately 30%,10% and 14.5%,respectively.The reduction rate of SNA（sulfate,nitrate and ammonium）concentrations was significantly higher than that of PM_（2.5） in 2017,implying that the current key strategy toward controlling air pollutants from the industrial sector is more powerful for SNA.Although air pollution control measures implemented in the industrial sector could greatly reduce total emissions,constraining the emissions from lower sources such as residential coal combustion would be more effective in decreasing the concentration of PM_（2.5） from 2017 to 2020.These results suggest that even for a typical industrial city,the reduction of PM_（2.5） concentrations not only requires decreases in emissions from the industrial sector,but also from the low emission sources.The seasonal variation in sulfate concentration also showed that emission from coal-burning is the key factor to control during the heating season.展开更多
Traditional air quality data have a spatial resolution of 1 km or above, making it challenging to resolve detailed air pollution exposure in complex urban areas. Combining urban morphology, dynamic traffic emission, r...Traditional air quality data have a spatial resolution of 1 km or above, making it challenging to resolve detailed air pollution exposure in complex urban areas. Combining urban morphology, dynamic traffic emission, regional and local meteorology, physicochemical transformations in air quality models using big data fusion technology, an ultra-fine resolution modeling system was developed to provide air quality data down to street level. Based on one-year ultra-fine resolution data, this study investigated the effects of pollution heterogeneity on the individual and population exposure to particulate matter(PM_(2.5)and PM_(10)),nitrogen dioxide(NO_(2)), and ozone(O_(3)) in Hong Kong, one of the most densely populated and urbanized cities. Sharp fine-scale variabilities in air pollution were revealed within individual city blocks. Using traditional 1 km average to represent individual exposure resulted in a positively skewed deviation of up to 200% for high-end exposure individuals. Citizens were disproportionally affected by air pollution, with annual pollutant concentrations varied by factors of 2 to 5 among 452 District Council Constituency Areas(DCCAs) in Hong Kong, indicating great environmental inequities among the population. Unfavorable city planning resulted in a positive spatial coincidence between pollution and population, which increased public exposure to air pollutants by as large as 46% among districts in Hong Kong. Our results highlight the importance of ultra-fine pollutant data in quantifying the heterogeneity in pollution exposure in the dense urban area and the critical role of smart urban planning in reducing exposure inequities.展开更多
Sodium-ion batteries(SIBs)hold great promise for large-scale energy storage in the post-lithium-ion battery era due to their high rate performance and long lifespan,although their sluggish Na^(+) transformation kineti...Sodium-ion batteries(SIBs)hold great promise for large-scale energy storage in the post-lithium-ion battery era due to their high rate performance and long lifespan,although their sluggish Na^(+) transformation kinetics still require improvement.Encouraged by the excellent electrochemical performance of titanium-based anode materials,here,we present a novel titanium vanadate@carbon(TVO@C)material as anode for SIBs.Our TVO@C material is synthesized via a facile coprecipitation method,with the following annealing process in an acetylene atomosphere.The opened ion channel and the oxygen vacancies within TVO@C facilitate the diffusion of Na^(+) ions,reducing their diffusion barrier.Thus,an ultrahigh rate of 100 A g^(-1)and long life of 10,000 cycles have been achieved.Furthermore,the TVO@C electrode exhibits stable performance,not only at room temperature,but also at temperatures as low as 20 C.The TVO@CjjNa_(3)V_(2)(PO_(4))_(3)@C full cells have also achieved stable discharge/charge for 500 cycles.It is believed that this strategy provides new insight into the development of advanced electrodes and provides a new opportunity for constructing novel high rate electrodes.展开更多
Understanding the influence of HCl on the NH_(3)-selective catalytic reduction reaction mechanism is crucial for designing highly efficient denitrification catalysts.The formation of chlorate species on the surface of...Understanding the influence of HCl on the NH_(3)-selective catalytic reduction reaction mechanism is crucial for designing highly efficient denitrification catalysts.The formation of chlorate species on the surface of the synthesized SbCeO_(x)catalyst,induced by HCl,significantly enhances low-temperature activity,as evidenced by a 30%increase in NO conversion at 155℃.Furthermore,it improves N_(2)selectivity at high temperatures,with a notable 17%increase observed at 405℃.Both experimental results and density functional theory calculations confirm that chlorate species form at Ce sites.This formation facilitates the creation of oxygen vacancies,boosting the oxygen exchange capacity.It also increases NH_(3)adsorption at the Ce sites,promotes the formation of Sb-OH,and reduces competitive OH adsorption on these sites.Notably,compared with the reaction mechanism without HCl,the presence of chlorate species enhances NH_(3)adsorption and activation,which is vital for subsequent catalytic reactions.展开更多
Nitrogen oxides(NO_(x))are crucial in tropospheric photochemical ozone(O_(3))production and oxidation capacity.Currently,the widely used NO_(x)measurement technique is chemiluminescence(CL)(CL-NO_(x)),which tends to o...Nitrogen oxides(NO_(x))are crucial in tropospheric photochemical ozone(O_(3))production and oxidation capacity.Currently,the widely used NO_(x)measurement technique is chemiluminescence(CL)(CL-NO_(x)),which tends to overestimate NO_(2)due to atmospheric oxidation products of NO_(x)(i.e.,NO_(z)).We developed and characterized a NO_(x)measurement system using the cavity attenuated phase shift(CAPS)technique(CAPS-NO_(x)),which is free from interferences with nitrogen-containing species.The NO_(x)measured by the CAPS-NO_(x)and CL-NO_(x)analyzers were compared.Results show that both analyzers showed consistent measurement results for NO,but the NO_(2)measured by the CAPS-NO_(x)analyzer(NO_(2)_CAPS)was mostly lower than that measured by the CL-NO_(x)analyzer(NO_(2)_CL),which led to the deviations in O_(3)formation sensitivity regime and O_(x)(=O_(3)+NO_(2))sources(i.e.,regional background and photochemically produced O_(x))determined by the ozone production efficiencies(OPE)calculated from NO_(2)_CL and NO_(2)_CAPS.Overall,OPE_CL exceeded OPE_CAPS by 18.9%,which shifted 3 out of 13 observation days from the VOCs-limited to the transition regime when judging using OPE_CL,as compared to calculations using OPE_CAPS.During the observation period,days dominated by regional background O_(x)accounted for 46%and 62%when determined using NO_(2)_CL and NO_(2)_CAPS,respectively.These findings suggest that the use of the CL-NO_(x)analyzer tends to underestimate both the VOCs-limited regime and the regional background O_(x)dominated days.The newly built CAPS-NO_(x)analyzer here can promote the accurate measurement of NO_(2),which is meaningful for diagnosing O_(3)formation regimes and O_(x)sources.展开更多
Roadside habitat through major urban areas may offer remnant examples of natural grasslands.These habitats may be subjected to frequent as mowing and exposure to automobile emissions and runoff.This study was conducte...Roadside habitat through major urban areas may offer remnant examples of natural grasslands.These habitats may be subjected to frequent as mowing and exposure to automobile emissions and runoff.This study was conducted on interstate highway right-of-ways in San Antonio,Texas,U.S.A.We compared the vegetation species and diversity,and the organic carbon of leaf litter,plants,and soils.Two non-native grasses accounted for 50.9% cover,while all native forbs and grasses accounted for only 9.8% cover.The mean biomass of nonnative grasseswas 4.5 times greater than that of all native species.Organic carbon content of leaf litter,plants,and soils was variable among the study sites,possibly due to management practices and a drought that occurred during the study.Themean organic carbon content in the upper 20 cm soil was 5.0 kg C/m^(2) and organic carbon content was greater in the upper 10 cm than organic carbon in the 10.1 to 20 cm portion.Cynodon dactylon and Bouteloua curtipendula exhibited the greatest photosynthesis efficiency indicating these grasses are more adaptable to hot summer temperatures found in Central Texas.The organic carbon content along a major interstate was 13,793 kg·C/ha for leaf litter,vegetation,and the upper 20 cm of the soil.We conclude that interstate highways provide habitat for some native species,but the vegetation along right-of-ways is dominated by two non-native grasses.It appears unlikely that roadside habitat can be restored to resemble native grasslands without large scale and costly restoration efforts.展开更多
Computational Fluids Dynamics(CFD)simulations are essential for optimizing the design of a cockpit’s internal environment,but the complex geometric models consume a significant amount of computational resources and t...Computational Fluids Dynamics(CFD)simulations are essential for optimizing the design of a cockpit’s internal environment,but the complex geometric models consume a significant amount of computational resources and time.Arbitrary simplification of geometric models may result in inaccurate calculations of physical fields.To address this issue,this study establishes a geometric model simplification strategy and successfully applies it to a cockpit.The implementation of the whole approach is divided into three steps,summarized in three methods,namely Sensitivity Analysis Method(SAM),Detail Suppression Method(DSM),and Evaluation Standards Method(ESM).Sensitivity analysis of the detailed features of the geometric model is performed using the adjoint method.The details of the geometric model are suppressed based on the principle of curvature continuity.After evaluation,the suppression degrees of detailed features with different sensitivity levels are obtained.The results demonstrate that this strategy can be employed to achieve precise simplification standards,thereby avoiding excessive deviations caused by arbitrary simplification and reducing the significant costs associated with trial-and-error simplification.展开更多
The Pearl River Delta(PRD)region has been identified as a significant hotspot of wet ammonium deposition.However,the absence of long-term monitoring data in the area hinders the comprehension of the historical trends ...The Pearl River Delta(PRD)region has been identified as a significant hotspot of wet ammonium deposition.However,the absence of long-term monitoring data in the area hinders the comprehension of the historical trends and changes in wet NH_(4)^(+)-N deposition in response to emissions,which interferes with the ability to make effective decisions.This study has analyzed the long-term trends of wet NH_(4)^(+)-N deposition flux and has quantified the effect of anthropogenic emissions and meteorological factors at a typical urban site and a typical forest site in the PRD region from 2009 to 2020.It revealed a significant decreasing trend in wet NH_(4)^(+)-N flux in both the typical urban and forest areas of the PRD region,at-6.2%/year(p<0.001)and-3.3%/year(p<0.001),respectively.Anthropogenic emissions are thought to have contributed 47%–57%of the wet NH_(4)^(+)-N deposition trend over the past 12 years compared to meteorological factors.Meteorological conditions dominated the interannual fluctuations in wet NH_(4)^(+)-N deposition with an absolute contribution of 46%–52%,while anthropogenic emissions change alone explained 10%–31%.NH_(3)emissions have the greatest impact on the urban area among anthropogenic emission factors,while SO_(2)emissions have the greatest impact on the forest area.Additionally,precipitation was identified as the primary meteorological driver for both sites.Our findings also imply that the benefits of NH_(3)emissions reductions might not immediately emerge due to interference from weather-related factors.展开更多
This study tracked the characteristics of atmospheric wet deposition of the toxic element arsenic(As)at both urban(Guangzhou(GZ))and forested(Dinghushan Natural Reserve(DHS))sites within the Pearl River Delta(PRD)regi...This study tracked the characteristics of atmospheric wet deposition of the toxic element arsenic(As)at both urban(Guangzhou(GZ))and forested(Dinghushan Natural Reserve(DHS))sites within the Pearl River Delta(PRD)region between 2016 and 2019,examining its correlation with rainfall patterns.Additionally,by employing backward trajectory analysis and the potential source contribution function(PSCF)in conjunction with pertinent emission inventories,we pinpointed the main pathways of atmospheric arsenic transport and evaluated the emission contributions from priority source areas.The study revealed that the atmospheric arsenic wet deposition fluxes at the GZ and DHS sites exhibited a trend of increase followed by a decrease over the four-year period.Wet season deposition fluxes were more than triple those of the dry season,with urban site showing a difference of over four times.Notably,wet season As deposition at both sites was predominantly affected by heavy rainfall from marine air masses,constituting 31%of the total deposition.The predominant trajectory directions contributing to arsenic deposition at GZ and DHS were northeast(55%)and south(53%),respectively.The primary source areas for both sites were largely outside the PRD region,with the GZ site having 80%to 95%of its source area in the non-PRD region,compared to 69%to 88%at the DHS site.Furthermore,non-PRD areas contributed approximately 65%to arsenic emissions for both sites,with the industrial sector being the dominant emission source,exceeding 97%of the total emissions.展开更多
The compositions and distributions of monoterpenes,isoprene,aromatics and sesquiterpene SOA tracers(SOAM,SOAI,SOAA and SOAS,respectively)at an island site(Da Wan Shan Island,DWS)were investigated in the context of the...The compositions and distributions of monoterpenes,isoprene,aromatics and sesquiterpene SOA tracers(SOAM,SOAI,SOAA and SOAS,respectively)at an island site(Da Wan Shan Island,DWS)were investigated in the context of the influence of continental and marine air masses over the Pearl River Estuary(PRE)region in winter 2021.The sum concentration of SOA tracers was 6.2–132.8 ng m^(−3),with SOAM and SOAI as the main components in both continental(scenarios A1 and A2)and marine air masses(scenario A3),as well as their combination(scenario A4).The highest and lowest levels of SOAM were observed in A1 and A3,respectively,which were mainly related to the variations in meteorological conditions,precursor concentrations,and the degree of photochemical processes.Higher MBTCA/HGA(3-methyl-1,2,3-butanetricarboxylic acid/3-hydroxyglutaric acid)ratios suggested a less significant contribution fromα-pinene to SOAM.The variations of SOAI in the different scenarios were associated with differences in relative humidity,particle acidity,and isoprene/NOx ratios.The respective highest and lowest concentrations of aromatics SOA tracers in A1 and A3 revealed the influence of anthropogenic precursors from upwind continental areas,which was confirmed by the correlation among biogenic and anthropogenic precursors.The results of the tracer-based-method suggested dominant contributions of SOAs from aromatics and monoterpenes,with the highest concentrations in A1.A WRF-Chem simulation revealed that the SOAs from the above precursors only contributed 12%–25%to the total SOA at DWS,while the spatial distributions of SOAs further highlighted that the abundance of SOAs over the PRE region in winter is highly associated with air masses transported from upwind continental areas.展开更多
Particulate levoglucosan is an important tracer for biomass burning emission in ambient air.However,recent studies question its reliability as a biomass burning tracer in Chinesemega cities due to important contributi...Particulate levoglucosan is an important tracer for biomass burning emission in ambient air.However,recent studies question its reliability as a biomass burning tracer in Chinesemega cities due to important contribution from potential non-biomass burning sources,such as cooking.To address this,we examined the dynamic variation and sources of levoglucosan using a chemical ionization mass spectrometer and other advanced instruments during Beijing’s summer of 2021.The average mass concentration of levoglucosan and its isomer(C_(6)H_(10)O_(5))was 0.025±0.014μg/m^(3),constituting 0.55%±0.32%of total organic carbon(OC)in this campaign.Despite cooking emissions contributing significantly to the organic aerosol(OA,20%),levoglucosan and its isomers correlated more strongly with biomass-burning related tracers(R>0.6),black carbon(R=0.72)and less so with cooking-related sources(R=0.3).This indicates that levoglucosan is primarily dominated by biomass-burning emissions rather than cooking in Beijing’s urban areas during summertime.The diurnal variation of levoglucosan concentrations highlighted the importance of daytime and nocturnal biomass burning emissions during polluted periods in Beijing.Using levoglucosan as a tracer to quantify the biomass burning OC(BBOC),we found good agreement on the time series of BBOC between the tracermethod and other independent source apportionmentmethod.This reaffirms the reliability of levoglucosan as a biomass burning tracer.Biomass burning contributed an average of 7%-8%to OC,highlighting its significant impact on Beijing’s summer air quality.Our study enhances understanding of biomass burning influences on ambient aerosol in typical urban areas.展开更多
Understanding the characteristics and driving factors behind changes in vegetation ecosystem resilience is crucial for mitigating both current and future impacts of climate change. Despite recent advances in resilienc...Understanding the characteristics and driving factors behind changes in vegetation ecosystem resilience is crucial for mitigating both current and future impacts of climate change. Despite recent advances in resilience research, significant knowledge gaps remain regarding the drivers of resilience changes. In this study, we investigated the dynamics of ecosystem resilience across China and identified potential driving factors using the kernel normalized difference vegetation index(kNDVI) from 2000 to 2020. Our results indicate that vegetation resilience in China has exhibited an increasing trend over the past two decades, with a notable breakpoint occurring around 2012. We found that precipitation was the dominant driver of changes in ecosystem resilience, accounting for 35.82% of the variation across China, followed by monthly average maximum temperature(Tmax) and vapor pressure deficit(VPD), which explained 28.95% and 28.31% of the variation, respectively. Furthermore, we revealed that daytime and nighttime warming has asymmetric impacts on vegetation resilience, with temperature factors such as Tmin and Tmax becoming more influential, while the importance of precipitation slightly decreases after the resilience change point. Overall, our study highlights the key roles of water availability and temperature in shaping vegetation resilience and underscores the asymmetric effects of daytime and nighttime warming on ecosystem resilience.展开更多
Heavy metal contamination of agricultural soils poses risks and hazards to humans. The remediation of heavy metal-polluted soils has become a hot topic in environmental science and engineering. In this review, the app...Heavy metal contamination of agricultural soils poses risks and hazards to humans. The remediation of heavy metal-polluted soils has become a hot topic in environmental science and engineering. In this review, the application of clay minerals for the remediation of heavy metal-polluted agricultural soils is summarized, in terms of their remediation effects and mechanisms, influencing factors, and future focus. Typical clay minerals, natural sepiolite, palygorskite, and bentonite, have been widely utilized for the in-situ immobilization of heavy metals in soils, especially Cd-polluted paddy soils and wastewater-irrigated farmland soils. Clay minerals are able to increase soil pH, decrease the chemical-extractable fractions and bioavailability of heavy metals in soils, and reduce the heavy metal contents in edible parts of plants. The immobilization effects have been confirmed in field-scale demonstrations and pot trials. Clay minerals can improve the environmental quality of soils and alleviate the hazards of heavy metals to plants. As main factors affecting the immobilization effects, the pH and water condition of soils have drawn academic attention. The remediation mechanisms mainly include liming, precipitation, and sorption effects. However, the molecular mechanisms of microscopic immobilization are unclear. F^ture studies should focus on the long-term stability and improvement of clay minerals in order to obtain a better remediation effect.展开更多
Coal combustion and mercury pollution are closely linked, and this relationship is particularly relevant in China, the world＇s largest coal consumer. This paper begins with a summary of recent China-specific studies ...Coal combustion and mercury pollution are closely linked, and this relationship is particularly relevant in China, the world＇s largest coal consumer. This paper begins with a summary of recent China-specific studies on mercury removal by air pollution control technologies and then provides an economic analysis of mercury abatement from these emission control technologies at coal-fired power plants in China. This includes a cost-effectiveness analysis at the enterprise and sector level in China using 2010 as a baseline and projecting out to 2020 and2030. Of the control technologies evaluated, the most cost-effective is a fabric filter installed upstream of the wet flue gas desulfurization system（FF ＋ WFGD）. Halogen injection（HI） is also a cost-effective mercury-specific control strategy, although it has not yet reached commercial maturity. The sector-level analysis shows that 193 tons of mercury was removed in 2010 in China＇s coal-fired power sector, with annualized mercury emission control costs of 2.7 billion Chinese Yuan. Under a projected 2030 Emission Control（EC） scenario with stringent mercury limits compared to Business As Usual（BAU） scenario, the increase of selective catalytic reduction systems（SCR） and the use of HI could contribute to 39 tons of mercury removal at a cost of 3.8 billion CNY. The economic analysis presented in this paper offers insights on air pollution control technologies and practices for enhancing atmospheric mercury control that can aid decision-making in policy design and private-sector investments.展开更多
Volatile organic compounds（VOCs） are crucial to control air pollution in major Chinese cities since VOCs are the dominant factor influencing ambient ozone level, and also an important precursor of secondary organic ...Volatile organic compounds（VOCs） are crucial to control air pollution in major Chinese cities since VOCs are the dominant factor influencing ambient ozone level, and also an important precursor of secondary organic aerosols. Vehicular evaporative emissions have become a major and growing source of VOC emissions in China. This study consists of lab tests, technology evaluation, emissions modeling, policy projections and cost-benefit analysis to draw a roadmap for China for controlling vehicular evaporative emissions. The analysis suggests that evaporative VOC emissions from China＇s light-duty gasoline vehicles were approximately 185,000 ton in 2010 and would peak at 1,200,000 ton in 2040 without control. The current control strategy implemented in China, as shown in business as usual（BAU） scenario, will barely reduce the long-term growth in emissions. Even if Stage II gasoline station vapor control policies were extended national wide（BAU ＋ extended Stage II）, there would still be over 400,000 ton fuel loss in 2050. In contrast, the implementation of on-board refueling vapor recovery（ORVR） on new cars could reduce 97.5% of evaporative VOCs by 2050（BAU ＋ ORVR/BAU ＋ delayed ORVR）. According to the results, a combined Stage II and ORVR program is a comprehensive solution that provides both short-term and long-term benefits. The net cost to achieve the optimal total evaporative VOC control is approximately 62 billion CNY in 2025 and 149 billion CNY in 2050.展开更多
Excessive leachate levels in landfills can be a major triggering mechanism for translational failure. The scope of this paper is to present the development of the calculation methods for limit equilibrium analysis of ...Excessive leachate levels in landfills can be a major triggering mechanism for translational failure. The scope of this paper is to present the development of the calculation methods for limit equilibrium analysis of translational failure of landfills and the effects of parametric variation on the factor of safety （FS） of landfills under different leachate buildup conditions. During the development of the calculation methods, 4 leachate buildup conditions are considered. The FS for an interface with high friction angle and low apparent cohesion generally drops much more quickly when leachate levels are increased than that for an interface under inverse conditions. The critical interface of a multilayer liner system with the lowest FS for the entire waste mass can shift from one to another with changes in the leachate levels. The different interfaces of a multilayer liner will have different FS-values under different leachate buildup conditions.展开更多
Volatile organic compounds(VOCs)with high toxicity and carcinogenicity are emitted from kinds of industries,which endanger human health and the environment.Adsorption is a promising method for the treatment of VOCs du...Volatile organic compounds(VOCs)with high toxicity and carcinogenicity are emitted from kinds of industries,which endanger human health and the environment.Adsorption is a promising method for the treatment of VOCs due to its low cost and high efficiency.In recent years,activated carbons,zeolites,and mesoporous materials are widely used to remove VOCs because of their high specific surface area and abundant porosity.However,the hydrophilic nature and low desorption rate of those materials limit their commercial application.Furthermore,the adsorption capacities of VOCs still need to be improved.Porous organic polymers(POPs)with extremely high porosity,structural diversity,and hydrophobic have been considered as one of the most promising candidates for VOCs adsorption.This review generalized the superiority of POPs for VOCs adsorption compared to other porous materials and summarized the studies of VOCs adsorption on different types of POPs.Moreover,the mechanism of competitive adsorption between water and VOCs on the POPs was discussed.Finally,a concise outlook for utilizing POPs for VOCs adsorption was discussed,noting areas in which further work is needed to develop the next-generation POPs for practical applications.展开更多
基金supported by the Science Fund for Creative Research Groups of the Natural Science Foundation of China (No. 21221004)the Special Fund of the State Key Joint Laboratory of Environment Simulation and Pollution Control (No. 12L05ESPC)+1 种基金the MEP’s Special Funds for Research on Public Welfares (No. 201309009, 2011467003)supported by the Program for New Century Excellent Talents in University (No. NCET-10-0532) and the China Scholarship Council
文摘Understanding the effectiveness of national air pollution controls is important for control policy design to improve the future air quality in China. This study evaluated the effectiveness of major national control policies implemented recently in China through a modeling analysis. The sulfur dioxide （SO2） control policy during the llth Five Year Plan period （2006-2010） had succeeded in reducing the national SO2 emission in 2010 by 14% from its 2005 level, which correspondingly reduced ambient SO2 and sulfate （SO42-） concentrations by 13%-15% and 8%-10% respectively over east China. The nitrogen oxides （NOx） control policy during the 12th Five Year Plan period （2011-2015） targets the reduction of the national NOx emission in 2015 by 10% on the basis of 2010. The simulation results suggest that such a reduction in NOx emission will reduce the ambient nitrogen dioxide （NO2）, nitrate （NO3-）, 1-hr maxima ozone （03） concentrations and total nitrogen deposition by 8%, 3%-14%, 2% and 2%--4%, respectively over east China. The application of new emission standards for power plants will further reduce the NO2, NO3-, 1-hr maxima 03 concentrations and total nitrogen deposition by 2%-4%, 1%-%, 0-2% and 1%-2%, respectively. Sensitivity analysis was conducted to evaluate the inter-provincial impacts of emission reduction in Beijing-Tianjin-Hebei and the Yangtze River Delta, which indicated the need to implement joint regional air pollution control.
文摘Gamma irradiation mutagenesis is a technique commonly used to induce seedlessness in citrus fruits. We compared fruit quality traits of eight different seeded mandarin varieties within the Israeli citrus breeding collection with those of their corresponding gamma-irradiated low-seeded mutants. The mandarin varieties compared were: “Rishon” with “Kedem”;“Michal” with irradiated “Michal”;“Merav” with “Meravit”;“Vered” with “Vardit”;“Ora” with “Or”;“Murcott” with “Mor”;“Shani” with irradiated “Shani”;“King” with irradiated “King”. Mutational breeding by gamma irradiation reduced average fruit seed number by 70% - 92%. Furthermore, mutational breeding by gamma irradiation delayed ripening of the early-season mandarin varieties “Rishon” and “Michal” by 8 - 13 days, but did not delay ripening of most mid- and late-season varieties. Gamma-irradia- tion mutagenesis also reduced fruit weight of seven of the eight tested low-seeded varieties by 6 - 41 g per fruit. Gamma-irradiation mutagenesis had variable effects on biochemical composition and nutritional quality, in that some irradiated clones presented no changes whereas other had either higher or lower levels of juice total soluble solids, acidity, vitamin C and total antioxidant activity. Finally, sensory evaluations by a trained panel revealed that the flavor of most of the low-seeded, gamma-irradiated varieties was slightly or significantly preferable to that of unirradiated varieties.
基金supported by the Special Scientific Research Fund of the Environmental Protection Commonwealth Section(Nos.201409003,201509020)
文摘The national Air Pollution Prevention and Control Action Plan required significant decreases in PM_（2.5） levels over China.To explore more effective emission abatement strategies in industrial cities,a case study was conducted in Baotou to evaluate the current national control measures.The total emissions of SO_2,NO_X,PM_（2.5） and NMVOC（non-methane volatile organic compounds） in Baotou were 211.2 Gg,156.1 Gg,28.8 Gg,and 48.5 Gg,respectively in 2013,and they would experience a reduction of 30.4%,26.6%,15.1%,and 8.7%,respectively in 2017 and 39.0%,32.0%,24.4%,and 12.9%,respectively in2020.The SO_2,NO_Xand PM_（2.5） emissions from the industrial sector would experience a greater decrease,with reductions of 37%,32.7 and 24.3%,respectively.From 2013 to 2020,the concentrations of SO_2,NO_2,and PM_（2.5） are expected to decline by approximately 30%,10% and 14.5%,respectively.The reduction rate of SNA（sulfate,nitrate and ammonium）concentrations was significantly higher than that of PM_（2.5） in 2017,implying that the current key strategy toward controlling air pollutants from the industrial sector is more powerful for SNA.Although air pollution control measures implemented in the industrial sector could greatly reduce total emissions,constraining the emissions from lower sources such as residential coal combustion would be more effective in decreasing the concentration of PM_（2.5） from 2017 to 2020.These results suggest that even for a typical industrial city,the reduction of PM_（2.5） concentrations not only requires decreases in emissions from the industrial sector,but also from the low emission sources.The seasonal variation in sulfate concentration also showed that emission from coal-burning is the key factor to control during the heating season.
基金sponsored by the HSBC 150th Anniversary Charity Programme through the PRAISE-HK projectsupported by the Research Grants Council of Hong Kong (Project Nos. GRF 16202120 and T31-603/21-N)+1 种基金the NSFC/RGC Joint Research Scheme (Grant No. N_HKUST609/21)the Special Fund Project for Science and Technology Innovation Strategy of Guangdong Province (Grant No. 2019B121205004)。
文摘Traditional air quality data have a spatial resolution of 1 km or above, making it challenging to resolve detailed air pollution exposure in complex urban areas. Combining urban morphology, dynamic traffic emission, regional and local meteorology, physicochemical transformations in air quality models using big data fusion technology, an ultra-fine resolution modeling system was developed to provide air quality data down to street level. Based on one-year ultra-fine resolution data, this study investigated the effects of pollution heterogeneity on the individual and population exposure to particulate matter(PM_(2.5)and PM_(10)),nitrogen dioxide(NO_(2)), and ozone(O_(3)) in Hong Kong, one of the most densely populated and urbanized cities. Sharp fine-scale variabilities in air pollution were revealed within individual city blocks. Using traditional 1 km average to represent individual exposure resulted in a positively skewed deviation of up to 200% for high-end exposure individuals. Citizens were disproportionally affected by air pollution, with annual pollutant concentrations varied by factors of 2 to 5 among 452 District Council Constituency Areas(DCCAs) in Hong Kong, indicating great environmental inequities among the population. Unfavorable city planning resulted in a positive spatial coincidence between pollution and population, which increased public exposure to air pollutants by as large as 46% among districts in Hong Kong. Our results highlight the importance of ultra-fine pollutant data in quantifying the heterogeneity in pollution exposure in the dense urban area and the critical role of smart urban planning in reducing exposure inequities.
基金supported by National Nature Science Foundation of China(22105118)Nature Science Foundation of Shandong Provinces(ZR2021QB095)China Postdoctoral Science Foundation(2020TQ0183 and 2021M701979).
文摘Sodium-ion batteries(SIBs)hold great promise for large-scale energy storage in the post-lithium-ion battery era due to their high rate performance and long lifespan,although their sluggish Na^(+) transformation kinetics still require improvement.Encouraged by the excellent electrochemical performance of titanium-based anode materials,here,we present a novel titanium vanadate@carbon(TVO@C)material as anode for SIBs.Our TVO@C material is synthesized via a facile coprecipitation method,with the following annealing process in an acetylene atomosphere.The opened ion channel and the oxygen vacancies within TVO@C facilitate the diffusion of Na^(+) ions,reducing their diffusion barrier.Thus,an ultrahigh rate of 100 A g^(-1)and long life of 10,000 cycles have been achieved.Furthermore,the TVO@C electrode exhibits stable performance,not only at room temperature,but also at temperatures as low as 20 C.The TVO@CjjNa_(3)V_(2)(PO_(4))_(3)@C full cells have also achieved stable discharge/charge for 500 cycles.It is believed that this strategy provides new insight into the development of advanced electrodes and provides a new opportunity for constructing novel high rate electrodes.
文摘Understanding the influence of HCl on the NH_(3)-selective catalytic reduction reaction mechanism is crucial for designing highly efficient denitrification catalysts.The formation of chlorate species on the surface of the synthesized SbCeO_(x)catalyst,induced by HCl,significantly enhances low-temperature activity,as evidenced by a 30%increase in NO conversion at 155℃.Furthermore,it improves N_(2)selectivity at high temperatures,with a notable 17%increase observed at 405℃.Both experimental results and density functional theory calculations confirm that chlorate species form at Ce sites.This formation facilitates the creation of oxygen vacancies,boosting the oxygen exchange capacity.It also increases NH_(3)adsorption at the Ce sites,promotes the formation of Sb-OH,and reduces competitive OH adsorption on these sites.Notably,compared with the reaction mechanism without HCl,the presence of chlorate species enhances NH_(3)adsorption and activation,which is vital for subsequent catalytic reactions.
基金supported by the Natural Science Foundation of Guangdong Province(No.2020A1515110526)the Key-Area Research and Development Programof Guangdong Province(No.2020B1111360003)the National Natural Science Foundation of China(No.42305096).
文摘Nitrogen oxides(NO_(x))are crucial in tropospheric photochemical ozone(O_(3))production and oxidation capacity.Currently,the widely used NO_(x)measurement technique is chemiluminescence(CL)(CL-NO_(x)),which tends to overestimate NO_(2)due to atmospheric oxidation products of NO_(x)(i.e.,NO_(z)).We developed and characterized a NO_(x)measurement system using the cavity attenuated phase shift(CAPS)technique(CAPS-NO_(x)),which is free from interferences with nitrogen-containing species.The NO_(x)measured by the CAPS-NO_(x)and CL-NO_(x)analyzers were compared.Results show that both analyzers showed consistent measurement results for NO,but the NO_(2)measured by the CAPS-NO_(x)analyzer(NO_(2)_CAPS)was mostly lower than that measured by the CL-NO_(x)analyzer(NO_(2)_CL),which led to the deviations in O_(3)formation sensitivity regime and O_(x)(=O_(3)+NO_(2))sources(i.e.,regional background and photochemically produced O_(x))determined by the ozone production efficiencies(OPE)calculated from NO_(2)_CL and NO_(2)_CAPS.Overall,OPE_CL exceeded OPE_CAPS by 18.9%,which shifted 3 out of 13 observation days from the VOCs-limited to the transition regime when judging using OPE_CL,as compared to calculations using OPE_CAPS.During the observation period,days dominated by regional background O_(x)accounted for 46%and 62%when determined using NO_(2)_CL and NO_(2)_CAPS,respectively.These findings suggest that the use of the CL-NO_(x)analyzer tends to underestimate both the VOCs-limited regime and the regional background O_(x)dominated days.The newly built CAPS-NO_(x)analyzer here can promote the accurate measurement of NO_(2),which is meaningful for diagnosing O_(3)formation regimes and O_(x)sources.
基金supported by the Transportation Consortium of South-Central States (No.18HSTSA01)support was provided by the University of San Antonio, Department of Integrated Biology from the principal investigator’s startup funds to support student research assistants.
文摘Roadside habitat through major urban areas may offer remnant examples of natural grasslands.These habitats may be subjected to frequent as mowing and exposure to automobile emissions and runoff.This study was conducted on interstate highway right-of-ways in San Antonio,Texas,U.S.A.We compared the vegetation species and diversity,and the organic carbon of leaf litter,plants,and soils.Two non-native grasses accounted for 50.9% cover,while all native forbs and grasses accounted for only 9.8% cover.The mean biomass of nonnative grasseswas 4.5 times greater than that of all native species.Organic carbon content of leaf litter,plants,and soils was variable among the study sites,possibly due to management practices and a drought that occurred during the study.Themean organic carbon content in the upper 20 cm soil was 5.0 kg C/m^(2) and organic carbon content was greater in the upper 10 cm than organic carbon in the 10.1 to 20 cm portion.Cynodon dactylon and Bouteloua curtipendula exhibited the greatest photosynthesis efficiency indicating these grasses are more adaptable to hot summer temperatures found in Central Texas.The organic carbon content along a major interstate was 13,793 kg·C/ha for leaf litter,vegetation,and the upper 20 cm of the soil.We conclude that interstate highways provide habitat for some native species,but the vegetation along right-of-ways is dominated by two non-native grasses.It appears unlikely that roadside habitat can be restored to resemble native grasslands without large scale and costly restoration efforts.
基金supported by the National Natural Science Foundation of China(Grant No.51878442).
文摘Computational Fluids Dynamics(CFD)simulations are essential for optimizing the design of a cockpit’s internal environment,but the complex geometric models consume a significant amount of computational resources and time.Arbitrary simplification of geometric models may result in inaccurate calculations of physical fields.To address this issue,this study establishes a geometric model simplification strategy and successfully applies it to a cockpit.The implementation of the whole approach is divided into three steps,summarized in three methods,namely Sensitivity Analysis Method(SAM),Detail Suppression Method(DSM),and Evaluation Standards Method(ESM).Sensitivity analysis of the detailed features of the geometric model is performed using the adjoint method.The details of the geometric model are suppressed based on the principle of curvature continuity.After evaluation,the suppression degrees of detailed features with different sensitivity levels are obtained.The results demonstrate that this strategy can be employed to achieve precise simplification standards,thereby avoiding excessive deviations caused by arbitrary simplification and reducing the significant costs associated with trial-and-error simplification.
基金supported by the National Natural Science Foundation(Nos.42275107,42121004,and 42375109)the National Key Research and Development Plan(No.2023YFC3706202)+1 种基金the Foundational and Applied Basic Research in Guangzhou in 2023(No.2023A04J0251)the Special Fund Project for Science and Technology Innovation Strategy of Guangdong Province(No.2019B121205004).
文摘The Pearl River Delta(PRD)region has been identified as a significant hotspot of wet ammonium deposition.However,the absence of long-term monitoring data in the area hinders the comprehension of the historical trends and changes in wet NH_(4)^(+)-N deposition in response to emissions,which interferes with the ability to make effective decisions.This study has analyzed the long-term trends of wet NH_(4)^(+)-N deposition flux and has quantified the effect of anthropogenic emissions and meteorological factors at a typical urban site and a typical forest site in the PRD region from 2009 to 2020.It revealed a significant decreasing trend in wet NH_(4)^(+)-N flux in both the typical urban and forest areas of the PRD region,at-6.2%/year(p<0.001)and-3.3%/year(p<0.001),respectively.Anthropogenic emissions are thought to have contributed 47%–57%of the wet NH_(4)^(+)-N deposition trend over the past 12 years compared to meteorological factors.Meteorological conditions dominated the interannual fluctuations in wet NH_(4)^(+)-N deposition with an absolute contribution of 46%–52%,while anthropogenic emissions change alone explained 10%–31%.NH_(3)emissions have the greatest impact on the urban area among anthropogenic emission factors,while SO_(2)emissions have the greatest impact on the forest area.Additionally,precipitation was identified as the primary meteorological driver for both sites.Our findings also imply that the benefits of NH_(3)emissions reductions might not immediately emerge due to interference from weather-related factors.
基金supported by the National Natural Science Foundation of China(Nos.42121004,42275107,and 42077205)the National Key Research and Development Plan(No.2023YFC3706202)+1 种基金the Foundational and Applied Basic Research in Guangzhou in 2023(No.2023A04J0251)the Special Fund Project for Science and Technology Innovation Strategy of Guangdong Province(No.2019B121205004)。
文摘This study tracked the characteristics of atmospheric wet deposition of the toxic element arsenic(As)at both urban(Guangzhou(GZ))and forested(Dinghushan Natural Reserve(DHS))sites within the Pearl River Delta(PRD)region between 2016 and 2019,examining its correlation with rainfall patterns.Additionally,by employing backward trajectory analysis and the potential source contribution function(PSCF)in conjunction with pertinent emission inventories,we pinpointed the main pathways of atmospheric arsenic transport and evaluated the emission contributions from priority source areas.The study revealed that the atmospheric arsenic wet deposition fluxes at the GZ and DHS sites exhibited a trend of increase followed by a decrease over the four-year period.Wet season deposition fluxes were more than triple those of the dry season,with urban site showing a difference of over four times.Notably,wet season As deposition at both sites was predominantly affected by heavy rainfall from marine air masses,constituting 31%of the total deposition.The predominant trajectory directions contributing to arsenic deposition at GZ and DHS were northeast(55%)and south(53%),respectively.The primary source areas for both sites were largely outside the PRD region,with the GZ site having 80%to 95%of its source area in the non-PRD region,compared to 69%to 88%at the DHS site.Furthermore,non-PRD areas contributed approximately 65%to arsenic emissions for both sites,with the industrial sector being the dominant emission source,exceeding 97%of the total emissions.
基金supported by the State Key Program of the National Natural Science Foundation of China(Grant Nos.42230701,91644215)the National Natural ScienceFoundation of China(Grant Nos.42122062 and 42307137)+3 种基金the Guangdong Basic and Applied Basic Research Foundation(Grant No.2022A1515010852)the Fundamental Research Funds for the Central Universities,Sun Yat-sen University(Grant No.23hytd002)the Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)(Grant No.SML2023SP218)L.M.acknowledges the Zhuhai Science and Technology Plan Project(Grant No.ZH22036201210115PWC).
文摘The compositions and distributions of monoterpenes,isoprene,aromatics and sesquiterpene SOA tracers(SOAM,SOAI,SOAA and SOAS,respectively)at an island site(Da Wan Shan Island,DWS)were investigated in the context of the influence of continental and marine air masses over the Pearl River Estuary(PRE)region in winter 2021.The sum concentration of SOA tracers was 6.2–132.8 ng m^(−3),with SOAM and SOAI as the main components in both continental(scenarios A1 and A2)and marine air masses(scenario A3),as well as their combination(scenario A4).The highest and lowest levels of SOAM were observed in A1 and A3,respectively,which were mainly related to the variations in meteorological conditions,precursor concentrations,and the degree of photochemical processes.Higher MBTCA/HGA(3-methyl-1,2,3-butanetricarboxylic acid/3-hydroxyglutaric acid)ratios suggested a less significant contribution fromα-pinene to SOAM.The variations of SOAI in the different scenarios were associated with differences in relative humidity,particle acidity,and isoprene/NOx ratios.The respective highest and lowest concentrations of aromatics SOA tracers in A1 and A3 revealed the influence of anthropogenic precursors from upwind continental areas,which was confirmed by the correlation among biogenic and anthropogenic precursors.The results of the tracer-based-method suggested dominant contributions of SOAs from aromatics and monoterpenes,with the highest concentrations in A1.A WRF-Chem simulation revealed that the SOAs from the above precursors only contributed 12%–25%to the total SOA at DWS,while the spatial distributions of SOAs further highlighted that the abundance of SOAs over the PRE region in winter is highly associated with air masses transported from upwind continental areas.
基金supported by the National Key R&D Program of China(Nos.2022YFC3701000 and 2021YFA1601800)the National Natural Science Foundation of China(Nos.42230701 and 42375105)+1 种基金the Foundation for Program of Science and Technology Research(No.2024A1515011937)Guangdong Foundation for Program of Science and Technology Research(No.2023B1212060049).
文摘Particulate levoglucosan is an important tracer for biomass burning emission in ambient air.However,recent studies question its reliability as a biomass burning tracer in Chinesemega cities due to important contribution from potential non-biomass burning sources,such as cooking.To address this,we examined the dynamic variation and sources of levoglucosan using a chemical ionization mass spectrometer and other advanced instruments during Beijing’s summer of 2021.The average mass concentration of levoglucosan and its isomer(C_(6)H_(10)O_(5))was 0.025±0.014μg/m^(3),constituting 0.55%±0.32%of total organic carbon(OC)in this campaign.Despite cooking emissions contributing significantly to the organic aerosol(OA,20%),levoglucosan and its isomers correlated more strongly with biomass-burning related tracers(R>0.6),black carbon(R=0.72)and less so with cooking-related sources(R=0.3).This indicates that levoglucosan is primarily dominated by biomass-burning emissions rather than cooking in Beijing’s urban areas during summertime.The diurnal variation of levoglucosan concentrations highlighted the importance of daytime and nocturnal biomass burning emissions during polluted periods in Beijing.Using levoglucosan as a tracer to quantify the biomass burning OC(BBOC),we found good agreement on the time series of BBOC between the tracermethod and other independent source apportionmentmethod.This reaffirms the reliability of levoglucosan as a biomass burning tracer.Biomass burning contributed an average of 7%-8%to OC,highlighting its significant impact on Beijing’s summer air quality.Our study enhances understanding of biomass burning influences on ambient aerosol in typical urban areas.
基金National Key Research and Development Program,No.2021xjkk0303。
文摘Understanding the characteristics and driving factors behind changes in vegetation ecosystem resilience is crucial for mitigating both current and future impacts of climate change. Despite recent advances in resilience research, significant knowledge gaps remain regarding the drivers of resilience changes. In this study, we investigated the dynamics of ecosystem resilience across China and identified potential driving factors using the kernel normalized difference vegetation index(kNDVI) from 2000 to 2020. Our results indicate that vegetation resilience in China has exhibited an increasing trend over the past two decades, with a notable breakpoint occurring around 2012. We found that precipitation was the dominant driver of changes in ecosystem resilience, accounting for 35.82% of the variation across China, followed by monthly average maximum temperature(Tmax) and vapor pressure deficit(VPD), which explained 28.95% and 28.31% of the variation, respectively. Furthermore, we revealed that daytime and nighttime warming has asymmetric impacts on vegetation resilience, with temperature factors such as Tmin and Tmax becoming more influential, while the importance of precipitation slightly decreases after the resilience change point. Overall, our study highlights the key roles of water availability and temperature in shaping vegetation resilience and underscores the asymmetric effects of daytime and nighttime warming on ecosystem resilience.
基金supported by the Central Public Research Institutes Basic Funds for Research and Development, China (No. 2016-szjj-wrxf-lxf)the National Natural Science Foundation of China (No. 41401362)the Funds for Science and Technology Innovation Project from the Chinese Academy of Agricultural Sciences (No. CAAS-XTCX-2016018)
文摘Heavy metal contamination of agricultural soils poses risks and hazards to humans. The remediation of heavy metal-polluted soils has become a hot topic in environmental science and engineering. In this review, the application of clay minerals for the remediation of heavy metal-polluted agricultural soils is summarized, in terms of their remediation effects and mechanisms, influencing factors, and future focus. Typical clay minerals, natural sepiolite, palygorskite, and bentonite, have been widely utilized for the in-situ immobilization of heavy metals in soils, especially Cd-polluted paddy soils and wastewater-irrigated farmland soils. Clay minerals are able to increase soil pH, decrease the chemical-extractable fractions and bioavailability of heavy metals in soils, and reduce the heavy metal contents in edible parts of plants. The immobilization effects have been confirmed in field-scale demonstrations and pot trials. Clay minerals can improve the environmental quality of soils and alleviate the hazards of heavy metals to plants. As main factors affecting the immobilization effects, the pH and water condition of soils have drawn academic attention. The remediation mechanisms mainly include liming, precipitation, and sorption effects. However, the molecular mechanisms of microscopic immobilization are unclear. F^ture studies should focus on the long-term stability and improvement of clay minerals in order to obtain a better remediation effect.
基金sponsored by the Major State Basic Research Development Program of China (973 Program) (No. 2013CB430001)the National Natural Science Foundation of China (No. 21307070)+1 种基金the MEP's Special Funds for Research on Public Welfares (201209015)the Sino-Norwegian cooperation project (SINOMER Ⅲ)
文摘Coal combustion and mercury pollution are closely linked, and this relationship is particularly relevant in China, the world＇s largest coal consumer. This paper begins with a summary of recent China-specific studies on mercury removal by air pollution control technologies and then provides an economic analysis of mercury abatement from these emission control technologies at coal-fired power plants in China. This includes a cost-effectiveness analysis at the enterprise and sector level in China using 2010 as a baseline and projecting out to 2020 and2030. Of the control technologies evaluated, the most cost-effective is a fabric filter installed upstream of the wet flue gas desulfurization system（FF ＋ WFGD）. Halogen injection（HI） is also a cost-effective mercury-specific control strategy, although it has not yet reached commercial maturity. The sector-level analysis shows that 193 tons of mercury was removed in 2010 in China＇s coal-fired power sector, with annualized mercury emission control costs of 2.7 billion Chinese Yuan. Under a projected 2030 Emission Control（EC） scenario with stringent mercury limits compared to Business As Usual（BAU） scenario, the increase of selective catalytic reduction systems（SCR） and the use of HI could contribute to 39 tons of mercury removal at a cost of 3.8 billion CNY. The economic analysis presented in this paper offers insights on air pollution control technologies and practices for enhancing atmospheric mercury control that can aid decision-making in policy design and private-sector investments.
基金supported by the National Natural Science Foundation of China (No. 71101078)the National High Technology Research and Development Program of China (No. 2013AA065303D)the National Environmental Protection Public Welfare Research Fund (No. 201209003 and No.201409021)
文摘Volatile organic compounds（VOCs） are crucial to control air pollution in major Chinese cities since VOCs are the dominant factor influencing ambient ozone level, and also an important precursor of secondary organic aerosols. Vehicular evaporative emissions have become a major and growing source of VOC emissions in China. This study consists of lab tests, technology evaluation, emissions modeling, policy projections and cost-benefit analysis to draw a roadmap for China for controlling vehicular evaporative emissions. The analysis suggests that evaporative VOC emissions from China＇s light-duty gasoline vehicles were approximately 185,000 ton in 2010 and would peak at 1,200,000 ton in 2040 without control. The current control strategy implemented in China, as shown in business as usual（BAU） scenario, will barely reduce the long-term growth in emissions. Even if Stage II gasoline station vapor control policies were extended national wide（BAU ＋ extended Stage II）, there would still be over 400,000 ton fuel loss in 2050. In contrast, the implementation of on-board refueling vapor recovery（ORVR） on new cars could reduce 97.5% of evaporative VOCs by 2050（BAU ＋ ORVR/BAU ＋ delayed ORVR）. According to the results, a combined Stage II and ORVR program is a comprehensive solution that provides both short-term and long-term benefits. The net cost to achieve the optimal total evaporative VOC control is approximately 62 billion CNY in 2025 and 149 billion CNY in 2050.
文摘Excessive leachate levels in landfills can be a major triggering mechanism for translational failure. The scope of this paper is to present the development of the calculation methods for limit equilibrium analysis of translational failure of landfills and the effects of parametric variation on the factor of safety （FS） of landfills under different leachate buildup conditions. During the development of the calculation methods, 4 leachate buildup conditions are considered. The FS for an interface with high friction angle and low apparent cohesion generally drops much more quickly when leachate levels are increased than that for an interface under inverse conditions. The critical interface of a multilayer liner system with the lowest FS for the entire waste mass can shift from one to another with changes in the leachate levels. The different interfaces of a multilayer liner will have different FS-values under different leachate buildup conditions.
基金supported by the National Key R&D Pro-gram of China(Nos.2019YFC1904100,2019YFC1904102,2019YFC1903902,and 2016YFC0205300)the National En-gineering Laboratory for Mobile Source Emission Control Technology of China(No.NELMS2017A03)+3 种基金the Natural Na-tional Science Foundation of China(Nos.21503144,21690083)Tianjin Research Program of Ecological Environmental Treat-ment(Nos.18ZXSZSF00210,18ZXSZSF00060)the Tianjin Research Program of Application Foundation and Advanced Technique(No.16JCQNJC05400)Major Science and Tech-nology Project for Ecological Environment Management in Tianjin(No.18ZXSZSF00210)。
文摘Volatile organic compounds(VOCs)with high toxicity and carcinogenicity are emitted from kinds of industries,which endanger human health and the environment.Adsorption is a promising method for the treatment of VOCs due to its low cost and high efficiency.In recent years,activated carbons,zeolites,and mesoporous materials are widely used to remove VOCs because of their high specific surface area and abundant porosity.However,the hydrophilic nature and low desorption rate of those materials limit their commercial application.Furthermore,the adsorption capacities of VOCs still need to be improved.Porous organic polymers(POPs)with extremely high porosity,structural diversity,and hydrophobic have been considered as one of the most promising candidates for VOCs adsorption.This review generalized the superiority of POPs for VOCs adsorption compared to other porous materials and summarized the studies of VOCs adsorption on different types of POPs.Moreover,the mechanism of competitive adsorption between water and VOCs on the POPs was discussed.Finally,a concise outlook for utilizing POPs for VOCs adsorption was discussed,noting areas in which further work is needed to develop the next-generation POPs for practical applications.
