An investigation on the process of ozone combined with hydrogen peroxide and ultraviolet radiation has been carried out in order to establish the kinetics for photochemical oxidation of polyacrylamide （PAM） in aqueo...An investigation on the process of ozone combined with hydrogen peroxide and ultraviolet radiation has been carried out in order to establish the kinetics for photochemical oxidation of polyacrylamide （PAM） in aqueous solution. Effects of operating parameters, including initial PAM concentration, dosages of ozone and hydrogen peroxide, UV radiation and pH value on the photochemical oxidation of PAM, have been studied. There was an increase in photochemical oxidation rate of PAM with increasing of dosages of 03, H2O2 and ultraviolet radiation. Upon increasing of the initial PAM concentration, the photochemical oxidation rate of PAM decreased. Slight effect of pH value on the photochemical oxidation rate of PAM was observed in the experiments. The kinetics equation for the photochemical oxidation of PAM by the system has been established.展开更多
This study reports an investigation into the degradation of 2,4-dichlorophenoxyacetic acid in bubble contactor column by O2/H2O2 process, which is widely used as a principal advanced oxidation process. The degradation...This study reports an investigation into the degradation of 2,4-dichlorophenoxyacetic acid in bubble contactor column by O2/H2O2 process, which is widely used as a principal advanced oxidation process. The degradation of 2,4-dichlorophenoxyacetic acid was studied under different H202/O3 molar ratio and pH value. Meanwhile, TOC removal was investigated both in distilled water and tap water. The influences of ozone transfer and consumed hydrogen peroxide were also discussed. The degradation products and oxidation intermediates were identified by GC-MS and LC-MS. A possible reaction mechanism was thus proposed.展开更多
The performance of UV/H_2O_2, UV/O_3, and UV/H_2O_2/O_3 oxidationsystems for the treatment of municipal solid-waste landfill leachatewas investigated. Main objective of the experiment was to removetotal organic carbon...The performance of UV/H_2O_2, UV/O_3, and UV/H_2O_2/O_3 oxidationsystems for the treatment of municipal solid-waste landfill leachatewas investigated. Main objective of the experiment was to removetotal organic carbon (TOC), non-biodegradable organic compounds(NBDOC) and color. In UV/H_2O_2 oxidation experiment, with theincrease of H_2O_2 dosage, removal efficiencies of TOC and coloralong with the ratio of biochemical oxygen demand (BOD) to chemicaloxygen demand (COD) of the effluent were increased and a betterperformance was obtained than the system H_2O_2 alone.展开更多
To solve the problem of shortened backwashing intervals in groundwater plants, several disinfectants including ozone（O3）, hydrogen peroxide（H2O2） and chlorine dioxide（Cl O2）were examined to peel off the film fro...To solve the problem of shortened backwashing intervals in groundwater plants, several disinfectants including ozone（O3）, hydrogen peroxide（H2O2） and chlorine dioxide（Cl O2）were examined to peel off the film from the quartz sand surface in four pilot-scale columns.An optimized oxidant dosage and oxidation time were determined by batch tests.Subsequently, the optimized conditions were tested in the four pilot-scale columns. The results demonstrated that the backwashing intervals increased from 35.17 to 54.33（H2O2）and to 53.67 hr（ClO2） after the oxidation treatments, and the increase of backwashing interval after treatment by O3 was much less than for the other two treatments.Interestingly, the treatment efficiency of filters was not affected by O3 or H2O2 oxidation;but after oxidation by ClO2, the treatment efficiency was deteriorated, especially the ammonia removal（from 96.96% to 24.95%）. The filter sands before and after the oxidation were characterized by scanning electron microscopy and X-ray photoelectron spectroscopy.Compared with the oxidation by O3 and H2O2, the structures on the surface of filter sands were seriously damaged after oxidation by ClO2. The chemical states of manganese on the surfaces of those treated sands were only changed by ClO2. The damage of the structures and the change of the chemical states of manganese might have a negative effect on the ammonia removal. In summary, H2O2 is a suitable agent for film peeling.展开更多
Severe ground-level ozone(O_(3))pollution over major Chinese cities has become one of the most challenging problems,which have deleterious effects on human health and the sustainability of society.This study explored ...Severe ground-level ozone(O_(3))pollution over major Chinese cities has become one of the most challenging problems,which have deleterious effects on human health and the sustainability of society.This study explored the spatiotemporal distribution characteristics of ground-level O_(3) and its precursors based on conventional pollutant and meteorological monitoring data in Zhejiang Province from 2016 to 2021.Then,a high-performance convolutional neural network(CNN)model was established by expanding the moment and the concentration variations to general factors.Finally,the response mechanism of O_(3) to the variation with crucial influencing factors is explored by controlling variables and interpolating target variables.The results indicated that the annual average MDA8-90th concentrations in Zhejiang Province are higher in the northern and lower in the southern.When the wind direction(WD)ranges from east to southwest and the wind speed(WS)ranges between 2 and 3 m/sec,higher O_(3) concentration prone to occur.At different temperatures(T),the O_(3) concentration showed a trend of first increasing and subsequently decreasing with increasing NO_(2) concentration,peaks at the NO_(2) concentration around 0.02mg/m^(3).The sensitivity of NO_(2) to O_(3) formation is not easily affected by temperature,barometric pressure and dew point temperature.Additionally,there is a minimum IRNO_(2) at each temperature when the NO_(2) concentration is 0.03 mg/m^(3),and this minimum IRNO_(2) decreases with increasing temperature.The study explores the response mechanism of O_(3) with the change of driving variables,which can provide a scientific foundation and methodological support for the targeted management of O_(3) pollution.展开更多
Objective weather classification methods have been extensively applied to identify dominant ozone-favorable synoptic weather patterns(SWPs),however,the consistency of different classification methods is rarely examine...Objective weather classification methods have been extensively applied to identify dominant ozone-favorable synoptic weather patterns(SWPs),however,the consistency of different classification methods is rarely examined.In this study,we apply two widely-used objective methods,the self-organizing map(SOM)and K-means clustering analysis,to derive ozone-favorable SWPs at four Chinese megacities in 2015-2022.We find that the two algorithms are largely consistent in recognizing dominant ozone-favorable SWPs for four Chinese megacities.In the case of classifying six SWPs,the derived circulation fields are highly similar with a spatial correlation of 0.99 between the two methods,and the difference in themean frequency of each SWP is less than 7%.The six dominant ozone-favorable SWPs in Guangzhou are all characterized by anomaly higher radiation and temperature,lower cloud cover,relative humidity,and wind speed,and stronger subsidence compared to climatology mean.We find that during 2015-2022,the occurrence of ozone-favorable SWPs days increases significantly at a rate of 3.2 days/year,faster than the increases in the ozone exceedance days(3.0 days/year).The interannual variability between the occurrence of ozone-favorable SWPs and ozone exceedance days are generally consistent with a temporal correlation coefficient of 0.6.In particular,the significant increase in ozone-favorable SWPs in 2022,especially the Subtropical High type which typically occurs in September,is consistent with a long-lasting ozone pollution episode in Guangzhou during September 2022.Our results thus reveal that enhanced frequency of ozone-favorable SWPs plays an important role in the observed 2015-2022 ozone increase in Guangzhou.展开更多
Extreme ozone pollution events(EOPEs)are associated with synoptic weather patterns(SWPs)and pose severe health and ecological risks.However,a systematic investigation of themeteorological causes,transport pathways,and...Extreme ozone pollution events(EOPEs)are associated with synoptic weather patterns(SWPs)and pose severe health and ecological risks.However,a systematic investigation of themeteorological causes,transport pathways,and source contributions to historical EOPEs is still lacking.In this paper,the K-means clustering method is applied to identify six dominant SWPs during the warm season in the Yangtze River Delta(YRD)region from 2016 to 2022.It provides an integrated analysis of the meteorological factors affecting ozone pollution in Hefei under different SWPs.Using the WRF-FLEXPART model,the transport pathways(TPPs)and geographical sources of the near-surface air masses in Hefei during EOPEs are investigated.The results reveal that Hefei experienced the highest ozone concentration(134.77±42.82μg/m^(3)),exceedance frequency(46 days(23.23%)),and proportion of EOPEs(21 instances,47.7%)under the control of peripheral subsidence of typhoon(Type 5).Regional southeast winds correlated with the ozone pollution in Hefei.During EOPEs,a high boundary layer height,solar radiation,and temperature;lowhumidity and cloud cover;and pronounced subsidence airflow occurred over Hefei and the broader YRD region.The East-South(E_S)patterns exhibited the highest frequency(28 instances,65.11%).Regarding the TPPs and geographical sources of the near-surface air masses during historical EOPEs.The YRD was the main source for land-originating air masses under E_S patterns(50.28%),with Hefei,southern Anhui,southern Jiangsu,and northern Zhejiang being key contributors.These findings can help improve ozone pollution early warning and control mechanisms at urban and regional scales.展开更多
Discharge plasma in and in contact with water can be accompanied with ultraviolet radiation and electron impact, thus can generate hydroxyl radicals, ozone, nitrite nitrogen and hydrogen peroxide. In this paper, a non...Discharge plasma in and in contact with water can be accompanied with ultraviolet radiation and electron impact, thus can generate hydroxyl radicals, ozone, nitrite nitrogen and hydrogen peroxide. In this paper, a non-equilibrium plasma processing system was established by means of an atmospheric pressure plasma jet immersed in water. The hydroxyl intensities and discharge energy waveforms were tested. The results show that the positive and negative discharge energy peaks were asymmetric, where the positive discharge energy peak was greater than the negative one. Meanwhile, the yield of ozone and nitrite nitrogen was enhanced with the increase of both the treatment time and the discharge energy. Moreover, the pH value of treated water was reduced rapidly and maintained at a lower level. The residual concentration of hydrogen peroxide in APPJ treated water was kept at a low level. Additionally, both the efficiency energy ratio of the yield of ozone and nitrite nitrogen and that of the removal of p-nitrophenol increased as a function of discharge energy and discharge voltage. The experimental results were fully analyzed and the chemical reaction equations and the physical processes of discharges in water were given.展开更多
Reuse of treated sewage effluent is an important option to overcome water scarcity.Conventional wastewater treatment methods are inadequate for the removal of several persistent contaminants such as pharmaceuticals an...Reuse of treated sewage effluent is an important option to overcome water scarcity.Conventional wastewater treatment methods are inadequate for the removal of several persistent contaminants such as pharmaceuticals and personal care products(PPCPs).In this study the removal of ibuprofen and gemfibrozil by ozonation and ozone/hydrogen peroxide(O3/H2O2)advanced oxidation process(AOP),as well as the formation of bromate were investigated at different temperatures and pH values.Complete removal of gemfibrozil and a maximum of 80%ibuprofen removal were achieved using ozone dosage of 1.5 mg/L with O3:H2O2 ratio of 1:0.25 in the O3/H2O2 process.The effect of temperature on the removal efficiency of these two compounds was found to be negligible from 25 to 40ᵒC for both processes.pH effect from 6 to 9 was also found to be negligible for gemfibrozil removal,while ibuprofen had relatively lower removal by ozonation at pH 6 compared to higher pH values.Bromate formation was decreased to 0.012 mg/L when the pH was increased to 9.Increasing the temperature to 40ᵒC also resulted in less bromate formation which was the lowest value obtained in this study at 0.0102 mg/L.Addition of H2O2 did not affect the formation of bromate and in some cases it was found to be slightly higher compared with ozonation treatment.展开更多
This study describes the use of the weighted multiplicative algebraic reconstruction technique(WMART)to obtain vertical ozone profiles from limb observations performed by the scanning imaging absorption spectrometer f...This study describes the use of the weighted multiplicative algebraic reconstruction technique(WMART)to obtain vertical ozone profiles from limb observations performed by the scanning imaging absorption spectrometer for atmospheric chartography(SCIAMACHY).This technique is based on SaskMART(the combination of the multiplicative algebraic reconstruction technique and SaskTRAN radiative transfer model),which was originally developed for optical spectrometer and infrared imaging system(OSIRIS)data.One of the objectives of this study was to obtain consistent ozone profiles from the two satellites.In this study,the WMART algorithm is combined with a radiative transfer model(SCIATRAN),as well as a set of measurement vectors comprising five Hartley pairing vectors(HPVs)and one Chappuis triplet vector(CTV),to retrieve ozone profiles in the altitude range of 10–69 km.Considering that the weighting factors in WMART have a significant effect on the retrievals,we propose a novel approach to calculate the pair/triplet weighting factors using wavelength weighting functions.The results of the application of the proposed ozone retrieval scheme are compared with the SCIAMACHY v3.5 ozone product by University of Bremen and validated against profiles derived from other passive satellite observations or measured by ozonesondes.Between 18 and 55 km,the retrieved ozone profiles typically agree with data from the SCIAMACHY ozone product within 5%for tropics and middle latitudes,whereas a negative deviation exists between 35 and 50 km for northern high latitudes,with a deviation of less than 10%above 50 km.Comparison of the retrieved profiles with microwave limb sounder(MLS)v5.0 indicates that the difference is within±5%between 18 and 55 km,and an agreement within 10%is achieved in other altitudes for tropics and middle latitudes.Comparison of the retrieved profiles with OSIRIS v7.1 indicates that the average deviation is within±5%between 20 and 59 km,and difference of approximately 10%is achieved below 20 km.Compared with ozonesondes data,a general validity of the retrievals is no more than 5%between 15 and 30 km.展开更多
Jeanologia,the global leader in sustainable textile technologies,is transforming textile finishing into a faster,cleaner,and more competitive process through its ground-breaking laser and ozone innovations.Technology ...Jeanologia,the global leader in sustainable textile technologies,is transforming textile finishing into a faster,cleaner,and more competitive process through its ground-breaking laser and ozone innovations.Technology at the core:Laser and Ozone The company's technological portfolio is led by two key solutions that are redefining industrial finishing.Laser Technology(exemplified by the Compact Super Flash system)delivers creativity,safety,quality,and natural aesthetics.It eliminates manual scraping,PP spray,and any hand touch,ensuring operator safety while boosting produc-tivity through automation and digital efficiency.It provides the best cost per garment and unparalleled design precision.展开更多
The Yangtze River Delta(YRD)region has witnessed a consistent decrease in NO_(2),CO,and PM_(2.5) from 2016 to 2023.However,ozone has exhibited fluctuating patterns.Quantifying ozone contributions from emissions,both w...The Yangtze River Delta(YRD)region has witnessed a consistent decrease in NO_(2),CO,and PM_(2.5) from 2016 to 2023.However,ozone has exhibited fluctuating patterns.Quantifying ozone contributions from emissions,both within and outside the YRD,is essential for understanding city-cluster-scale ozone pollution(CCSOP).To address these concerns,a comprehensive approach combining Kolmogorov-Zurbenko filtering,Empirical Orthogonal Function,Absolute Principal Component Score,andMultiple Linear Regression methods(KZ-EOF-APCs-MLR)was employed to quantify the impacts of meteorological factors,local and non-local emission contributions of ozone(LECO and NECO).Emission changes were identified as the predominant factor shaping annual fluctuations in ambient ozone.Notably,during the previous andmiddle stages of the COVID-19 pandemic(from2017 to 2021),emissions reductions led to a marked decrease in YRD ozone levels(-7.01μg/m^(3)),with a pronounced rebound post-pandemic(2022 to 2023)(+8.04μg/m^(3)).Seasonally,the emissioninduced ozone exhibited fluctuating upward trend during autumn and winter,suggesting a transition of ozone pollution towards colder seasons.Spatially,high LECO concentrated in the eastern YRD(EYRD)across spring,autumn,and winter,becoming prominent in the central YRD(CYRD)during summer.During CCSOP,the CYRD exhibited the highest LECO and exceedance frequency(20.82μg/m^(3) and 45.27%).LECO explained a large portion of ozone variability during CCSOP,particularly in the EYRD,while NECO showed less explanatory power but consistently high contributions(148.05±15.52μg/m^(3)).These findings offer valuable insights for a deeper understanding of the evolving patterns of ozone pollution and the issue of CCSOP in the YRD.展开更多
To better understand the effects of ground-level ozone(O_(3))on nutrients and stoichiometry in different plant organs,urban tree species Celtis sinensis,Cyclocarya paliu-rus,Quercus acutissima,and Quercus nuttallii we...To better understand the effects of ground-level ozone(O_(3))on nutrients and stoichiometry in different plant organs,urban tree species Celtis sinensis,Cyclocarya paliu-rus,Quercus acutissima,and Quercus nuttallii were sub-jected to a constant exposure to charcoal-filtered air(CF),nonfiltered air(NF),or NF+40,60,or 80 nmol O_(3)mol^(-1)(NF40,NF60,and NF80)starting early in the summer of the growing season.At the end of summer,net CO_(2)assimila-tion rate(A),stomatal conductance(gs),leaf mass per area(LMA),and/or leaf greenness(SPAD)either were not sig-nificantly affected by elevated O_(3)or were even higher in some cases during the summer compared with the CF or NF controls.LMA was significantly lower in autumn only after the highest O_(3)exposures.Compared to NF,NF40 caused a large increase in gs across species in late summer and more K and Mn in stems.At the end of the growing season,nutri-ent status and stoichiometric ratios in different organs were variously altered under O_(3)stress;many changes were large and often species-specific.Across O_(3)treatments,LMA was primarily associated with C and Mg levels in leaves and Ca levels in leaves and stems.NF40 enriched K,P,Fe,and Mn in stems,relative to NF,and NF60 enhanced Ca in leaves relative to CF and NF40.Moreover,NF resulted in a higher Ca/Mg ratio in leaves of Q.acutissima only,relative to the other O_(3)regimes.Interestingly,across species,O_(3)stress led to different nutrient modifications in different organs(stems+branches vs leaves).Thus,ambient and/or elevated O_(3)exposures can alter the dynamics and distribution of nutrients and disrupt stoichiometry in different organs in a species-specific manner.Changes in stoichiometry reflect an important defense mechanism in plants under O_(3),and O_(3)pollution adds more risk to ecological stoichiometries in urban areas.展开更多
[Objectives]To investigate the clinical efficacy of duloxetine combined with ozone pain point injection for the treatment of fibromyalgia(FM)and assess the effects of this combination therapy on pain,depression,and sl...[Objectives]To investigate the clinical efficacy of duloxetine combined with ozone pain point injection for the treatment of fibromyalgia(FM)and assess the effects of this combination therapy on pain,depression,and sleep disorders.[Methods]A randomized controlled crossover design was employed in this study.Sixty inpatients diagnosed with FM were allocated into three groups:the duloxetine group,the ozone group,and the combination therapy group,with each group consisting of 20 participants.The treatment duration was set at 4 weeks.The Visual Analogue Scale(VAS),the Fibromyalgia Impact Questionnaire(FIQ),the Hamilton Depression Scale(HAMD),the Pittsburgh Sleep Quality Index(PSQI),and the number of tender points were assessed prior to treatment,2 weeks post treatment,and 4 weeks post treatment.[Results]There were no statistically significant differences in various indicators among the three groups of patients prior to treatment.Following treatment,the VAS,FIQ,HAMD,PSQI,and the number of tender points in all three groups exhibited significant improvements(P<0.05).Notably,the combination therapy group demonstrated the most substantial reductions in each score,surpassing the improvements observed in the single application group(P<0.05).[Conclusions]Duloxetine combined with ozone pain point injection demonstrates a synergistic effect in alleviating pain,reducing depression,and enhancing sleep quality in patients with FM.This combination therapy exhibits superior efficacy compared to monotherapy and holds significant potential for clinical application.展开更多
We used observed concentrations of air pollutants,reanalyzed meteorological parameters,and results from the Goddard Earth Observing System Chemical Transport Model to examine the relationships between concentrations o...We used observed concentrations of air pollutants,reanalyzed meteorological parameters,and results from the Goddard Earth Observing System Chemical Transport Model to examine the relationships between concentrations of maximum daily 8-h average ozone(MDA8 O_(3)),PM_(2.5)(particulate matter with diameter of 2.5μm or less),and PM_(2.5)components and 2-m temperature(T2)or relative humidity(RH),as well as the effectiveness of precursor emission reductions on the control of O_(3) and PM_(2.5) in Beijing–Tianjin–Hebei(BTH)under different summertime temperature and humidity conditions.Both observed(simulated)MDA8 O_(3) and PM_(2.5) concentrations increased as T2 went up,with linear trends of 4.8(3.2)ppb℃^(−1) and 1.9(1.5)μg m^(−3)℃^(−1),respectively.Model results showed that the decreases in MDA8 O_(3) from precursor emission reductions were more sensitive to T2 than to RH.Reducing a larger proportion of volatile organic compound(VOC)emissions at higher T2 was more effective for the control of summertime O_(3) in BTH.For the control of summertime PM_(2.5) in BTH,reducing nitrogen oxides(NOx)combined with a small proportion of VOCs was the best measure.The magnitude of reduction in PM_(2.5) from reducing precursor emissions was more sensitive to RH than to T2,with the best efficiency at high RH.Results from this study are helpful for formulating effective policies to tackle O_(3) and PM_(2.5) pollution in BTH.展开更多
A novel system for measuring net photochemical ozone production rates in the atmosphere based on cavity ring-down spectroscopy(OPR-CRDS)was developed.The system consists of two chambers(a reaction chamber and a refere...A novel system for measuring net photochemical ozone production rates in the atmosphere based on cavity ring-down spectroscopy(OPR-CRDS)was developed.The system consists of two chambers(a reaction chamber and a reference chamber)and a dual-channel O_(x)-CRDS detector.To minimize the wall loss of O_(x)in the chambers,the inner surfaces of both chambers are coated with Teflon film.The performance of the OPR-CRDS system was characterized.It was found that even though the photolysis frequency(J value)decreased by 10%,the decrease in the P(O_(3))caused by the ultraviolet-blocking film coating was less than 3%.The two chambers had a good consistency in the mean residence time and the measurement of NO_(2)and O_(x)under the condition of no sunlight.The detection limit of the OPR-CRDS was determined to be 0.20 ppbv/hr.To further verify the accuracy of the system,the direct measurement values of the OPR-CRDS systemwere comparedwith the calculation results based on radical(OH,HO_(2),and RO_(2))reactions,and a good correlation was obtained between the measured and calculated values.Finally,the developed instrument was applied to obtain the comprehensive field observations at an urban site in the Yangtze River Delta(China)for 40 days,the time series and change characteristics of the P(O_(3))were obtained directly,and the good environmental adaptability and stability of the OPR-CRDS system were demonstrated.It is expected that the new instrument will be beneficial to investigations of the relationship between P(O_(3))and its precursors.展开更多
Due to the control of ozone(O_(3))-depleting substances(ODSs),it is believed that stratospheric O_(3)will recover in the future.However,in the context of global change,the contributions of other factors to O_(3)recove...Due to the control of ozone(O_(3))-depleting substances(ODSs),it is believed that stratospheric O_(3)will recover in the future.However,in the context of global change,the contributions of other factors to O_(3)recovery are also worth discussing.This paper investigates the independent and joint influences of changes in global methane(CH_(4)),carbon dioxide(CO_(2))and sea surface temperature(SST)on stratospheric O_(3)under the Representative Concentration Pathway(RCP)8.5 scenario in 2050 using sensitivity experiments with the Whole Atmosphere Community Climate Model,version4.Results show that,in the polar lower stratosphere,CH_(4)can reduce ODSs via chemical processes and further increase stratospheric O_(3)and temperature,which tends to reduce polar stratospheric clouds.This acts as positive feedback to O_(3)recovery.The increase of CH_(4)in the sensitivity experiments(CH_(4)is adjusted to match the 2050 levels under the RCP8.5scenario)could lead to a polar O_(3)recovery of about 27.9 DU in the Arctic.Increased CO_(2)(CO_(2) is adjusted to match the 2050 levels under the RCP8.5 scenario)can indirectly lead to a 6.5 DU increase in global total column O_(3)(TCO)through radiative effects,while the influence of SST on TCO in tropical regions can reach-3.3%.For the joint impact of CH_(4),CO_(2)and SST changes,CH_(4)can account for up to 69.0%of the TCO variations in the Antarctic region.Finally,we compare the effects of CH_(4)and ODSs on O_(3)in the polar regions in future experiments based on the RCP8.5 scenario.We find that ODSs are a dominant factor in O_(3)depletion in both poles;however,after 2040,the influence of increased CH_(4)on O_(3)recovery in the Arctic will surpass the effect of decreased ODSs.It implies that the future increase in CH_(4)may have an important impact on O_(3).展开更多
Ozone(O_(3))pollution has elevated in China,threatening plants and crop production.Ethylenediurea(EDU)is a chemical alleviating O_(3)-induced phytotoxicities.This study aimed at revealing fluctuating O_(3) exposures e...Ozone(O_(3))pollution has elevated in China,threatening plants and crop production.Ethylenediurea(EDU)is a chemical alleviating O_(3)-induced phytotoxicities.This study aimed at revealing fluctuating O_(3) exposures effects on Youxian No 3(Phaseolus vulgaris)and Sukui No 4(Vigna angularis),two widely grown Chinese bean cultivars,and EDU role in mediating these effects.Plants were periodically treated with EDU(400 mg/L)or water and subjected to charcoal-filtered air(CF)or non-filtered ambient air enriched with an additional targeted O_(3) concentration of 40 ppb(NF40).with subsequent ambient or NF40 exposures.A 10-day exposure to NF40 increased photosynthetic rate(A)while decreasing the leaf intercellular CO_(2) concentration(Ci),but this effect was absent after moving plants to ambient air for two weeks.Moving previously CF-exposed plants to ambient air for two weeks also increased A,which was not linked with Ci but more related to stomatal conductance(gs).Following two one-week and two-week sequential exposures of all plants to NF40,with an intermediate exposure to ambient air,elevated O_(3) reduced chlorophylls(SPAD),A,gs,Ci,and transpiration and decoupled A-gs response.More O_(3) effectswere observed in plants treatedwithNF40 during each O_(3)-treatment cycle,compared to those exposed to CF during the first cycle.The former plants exhibited significantly decreased biomass and water content of leaves and stems but increased flowers biomass and water content.Some of the effects were cultivardependent,with Youxian showing more apparent trade-offs between vegetative growth and reproduction.EDU alleviated various negative O_(3) effects.展开更多
For the effective treatment of the wastewater with low-medium concentration ammonia nitrogen and low strength COD,a high-performance Co_(3)O_(4) catalyst supported on carbon nanocages(CNCs)was prepared.By isovolumetri...For the effective treatment of the wastewater with low-medium concentration ammonia nitrogen and low strength COD,a high-performance Co_(3)O_(4) catalyst supported on carbon nanocages(CNCs)was prepared.By isovolumetric im pregnation,Co_(3)O_(4) could be uniformly dispersed on surface of CNCs,which possess tiny particle size and strong electron transfer capability.The catalytic performance of the prepared Co_(3)O_(4)/CNCs catalysts with different Co_(3)O_(4) loadings was systematically evaluated and compared with Co_(3)O_(4)/CNTs.It is found that 20 wt.%Co_(3)O_(4)/CNCs shows the best catalytic performance,achieving an ammonia nitrogen conversion rate of 71.0%and a nitrogen selectivity of 81.8%.Compared to commonly used Co_(3)O_(4),ammonia conversion and nitrogen selectivity of Co_(3)O_(4)/CNCs increased by 28.9%and 15.8%respectively.In the five consecutive cycles,the catalytic activity remained stable.The mechanism that CNCs support effectively increases the surface oxygen vacancies of Co_(3)O_(4) through XPS analysis was also elucidated,and DFT calculations confirm strong electron transfer between CNCs and Co_(3)O_(4),rendering Co_(3)O_(4) nanoparticles as the primary catalytic active sites.The results may contribute to the development of highperformance catalytic ozone oxidation catalysts for ammonia nitrogen.展开更多
文摘An investigation on the process of ozone combined with hydrogen peroxide and ultraviolet radiation has been carried out in order to establish the kinetics for photochemical oxidation of polyacrylamide （PAM） in aqueous solution. Effects of operating parameters, including initial PAM concentration, dosages of ozone and hydrogen peroxide, UV radiation and pH value on the photochemical oxidation of PAM, have been studied. There was an increase in photochemical oxidation rate of PAM with increasing of dosages of 03, H2O2 and ultraviolet radiation. Upon increasing of the initial PAM concentration, the photochemical oxidation rate of PAM decreased. Slight effect of pH value on the photochemical oxidation rate of PAM was observed in the experiments. The kinetics equation for the photochemical oxidation of PAM by the system has been established.
基金The National Natural Science Foundation of China (No. 50378028)
文摘This study reports an investigation into the degradation of 2,4-dichlorophenoxyacetic acid in bubble contactor column by O2/H2O2 process, which is widely used as a principal advanced oxidation process. The degradation of 2,4-dichlorophenoxyacetic acid was studied under different H202/O3 molar ratio and pH value. Meanwhile, TOC removal was investigated both in distilled water and tap water. The influences of ozone transfer and consumed hydrogen peroxide were also discussed. The degradation products and oxidation intermediates were identified by GC-MS and LC-MS. A possible reaction mechanism was thus proposed.
文摘The performance of UV/H_2O_2, UV/O_3, and UV/H_2O_2/O_3 oxidationsystems for the treatment of municipal solid-waste landfill leachatewas investigated. Main objective of the experiment was to removetotal organic carbon (TOC), non-biodegradable organic compounds(NBDOC) and color. In UV/H_2O_2 oxidation experiment, with theincrease of H_2O_2 dosage, removal efficiencies of TOC and coloralong with the ratio of biochemical oxygen demand (BOD) to chemicaloxygen demand (COD) of the effluent were increased and a betterperformance was obtained than the system H_2O_2 alone.
基金supported by the National Natural Science Foundation of China (Nos.51278409, 51308438)the Natural Science Foundation of Shaanxi Province (No.2014JZ015)the Research Program of China State Construction Engineering Corporation Ltd.(No.CSCEC-2014-Z-32)
文摘To solve the problem of shortened backwashing intervals in groundwater plants, several disinfectants including ozone（O3）, hydrogen peroxide（H2O2） and chlorine dioxide（Cl O2）were examined to peel off the film from the quartz sand surface in four pilot-scale columns.An optimized oxidant dosage and oxidation time were determined by batch tests.Subsequently, the optimized conditions were tested in the four pilot-scale columns. The results demonstrated that the backwashing intervals increased from 35.17 to 54.33（H2O2）and to 53.67 hr（ClO2） after the oxidation treatments, and the increase of backwashing interval after treatment by O3 was much less than for the other two treatments.Interestingly, the treatment efficiency of filters was not affected by O3 or H2O2 oxidation;but after oxidation by ClO2, the treatment efficiency was deteriorated, especially the ammonia removal（from 96.96% to 24.95%）. The filter sands before and after the oxidation were characterized by scanning electron microscopy and X-ray photoelectron spectroscopy.Compared with the oxidation by O3 and H2O2, the structures on the surface of filter sands were seriously damaged after oxidation by ClO2. The chemical states of manganese on the surfaces of those treated sands were only changed by ClO2. The damage of the structures and the change of the chemical states of manganese might have a negative effect on the ammonia removal. In summary, H2O2 is a suitable agent for film peeling.
基金supported by the National Key Research and Development Program of China (Nos.2022YFC3702000 and 2022YFC3703500)the Key R&D Project of Zhejiang Province (No.2022C03146).
文摘Severe ground-level ozone(O_(3))pollution over major Chinese cities has become one of the most challenging problems,which have deleterious effects on human health and the sustainability of society.This study explored the spatiotemporal distribution characteristics of ground-level O_(3) and its precursors based on conventional pollutant and meteorological monitoring data in Zhejiang Province from 2016 to 2021.Then,a high-performance convolutional neural network(CNN)model was established by expanding the moment and the concentration variations to general factors.Finally,the response mechanism of O_(3) to the variation with crucial influencing factors is explored by controlling variables and interpolating target variables.The results indicated that the annual average MDA8-90th concentrations in Zhejiang Province are higher in the northern and lower in the southern.When the wind direction(WD)ranges from east to southwest and the wind speed(WS)ranges between 2 and 3 m/sec,higher O_(3) concentration prone to occur.At different temperatures(T),the O_(3) concentration showed a trend of first increasing and subsequently decreasing with increasing NO_(2) concentration,peaks at the NO_(2) concentration around 0.02mg/m^(3).The sensitivity of NO_(2) to O_(3) formation is not easily affected by temperature,barometric pressure and dew point temperature.Additionally,there is a minimum IRNO_(2) at each temperature when the NO_(2) concentration is 0.03 mg/m^(3),and this minimum IRNO_(2) decreases with increasing temperature.The study explores the response mechanism of O_(3) with the change of driving variables,which can provide a scientific foundation and methodological support for the targeted management of O_(3) pollution.
基金supported by the Guangdong Basic and Applied Basic Research project (No.2020B0301030004)the Key-Area Research and Development Program of Guangdong Province (No.2020B1111360003)+1 种基金the National Natural Science Foundation of China (No.42105103)the Guangdong Basic and Applied Basic Research Foundation (No.2022A1515011554).
文摘Objective weather classification methods have been extensively applied to identify dominant ozone-favorable synoptic weather patterns(SWPs),however,the consistency of different classification methods is rarely examined.In this study,we apply two widely-used objective methods,the self-organizing map(SOM)and K-means clustering analysis,to derive ozone-favorable SWPs at four Chinese megacities in 2015-2022.We find that the two algorithms are largely consistent in recognizing dominant ozone-favorable SWPs for four Chinese megacities.In the case of classifying six SWPs,the derived circulation fields are highly similar with a spatial correlation of 0.99 between the two methods,and the difference in themean frequency of each SWP is less than 7%.The six dominant ozone-favorable SWPs in Guangzhou are all characterized by anomaly higher radiation and temperature,lower cloud cover,relative humidity,and wind speed,and stronger subsidence compared to climatology mean.We find that during 2015-2022,the occurrence of ozone-favorable SWPs days increases significantly at a rate of 3.2 days/year,faster than the increases in the ozone exceedance days(3.0 days/year).The interannual variability between the occurrence of ozone-favorable SWPs and ozone exceedance days are generally consistent with a temporal correlation coefficient of 0.6.In particular,the significant increase in ozone-favorable SWPs in 2022,especially the Subtropical High type which typically occurs in September,is consistent with a long-lasting ozone pollution episode in Guangzhou during September 2022.Our results thus reveal that enhanced frequency of ozone-favorable SWPs plays an important role in the observed 2015-2022 ozone increase in Guangzhou.
基金supported by the National Natural Science Foundation of China(Nos.U19A2044,42105132,42030609,and 41975037)the National Key Research and Development Programof China(No.2022YFC3700303).
文摘Extreme ozone pollution events(EOPEs)are associated with synoptic weather patterns(SWPs)and pose severe health and ecological risks.However,a systematic investigation of themeteorological causes,transport pathways,and source contributions to historical EOPEs is still lacking.In this paper,the K-means clustering method is applied to identify six dominant SWPs during the warm season in the Yangtze River Delta(YRD)region from 2016 to 2022.It provides an integrated analysis of the meteorological factors affecting ozone pollution in Hefei under different SWPs.Using the WRF-FLEXPART model,the transport pathways(TPPs)and geographical sources of the near-surface air masses in Hefei during EOPEs are investigated.The results reveal that Hefei experienced the highest ozone concentration(134.77±42.82μg/m^(3)),exceedance frequency(46 days(23.23%)),and proportion of EOPEs(21 instances,47.7%)under the control of peripheral subsidence of typhoon(Type 5).Regional southeast winds correlated with the ozone pollution in Hefei.During EOPEs,a high boundary layer height,solar radiation,and temperature;lowhumidity and cloud cover;and pronounced subsidence airflow occurred over Hefei and the broader YRD region.The East-South(E_S)patterns exhibited the highest frequency(28 instances,65.11%).Regarding the TPPs and geographical sources of the near-surface air masses during historical EOPEs.The YRD was the main source for land-originating air masses under E_S patterns(50.28%),with Hefei,southern Anhui,southern Jiangsu,and northern Zhejiang being key contributors.These findings can help improve ozone pollution early warning and control mechanisms at urban and regional scales.
基金supported by National Natural Science Foundation of China(Nos.11274092,11404092,61401146)the Nantong Science and Technology Project,Nantong,China(No.BK2014024)+1 种基金the Open Project of Jiangsu Province Key Laboratory of Environmental Engineering,Nanjing,China(No.KF2014001)the Fundamental Research Funds for the Central Universities of China(No.2014B11414)
文摘Discharge plasma in and in contact with water can be accompanied with ultraviolet radiation and electron impact, thus can generate hydroxyl radicals, ozone, nitrite nitrogen and hydrogen peroxide. In this paper, a non-equilibrium plasma processing system was established by means of an atmospheric pressure plasma jet immersed in water. The hydroxyl intensities and discharge energy waveforms were tested. The results show that the positive and negative discharge energy peaks were asymmetric, where the positive discharge energy peak was greater than the negative one. Meanwhile, the yield of ozone and nitrite nitrogen was enhanced with the increase of both the treatment time and the discharge energy. Moreover, the pH value of treated water was reduced rapidly and maintained at a lower level. The residual concentration of hydrogen peroxide in APPJ treated water was kept at a low level. Additionally, both the efficiency energy ratio of the yield of ozone and nitrite nitrogen and that of the removal of p-nitrophenol increased as a function of discharge energy and discharge voltage. The experimental results were fully analyzed and the chemical reaction equations and the physical processes of discharges in water were given.
文摘Reuse of treated sewage effluent is an important option to overcome water scarcity.Conventional wastewater treatment methods are inadequate for the removal of several persistent contaminants such as pharmaceuticals and personal care products(PPCPs).In this study the removal of ibuprofen and gemfibrozil by ozonation and ozone/hydrogen peroxide(O3/H2O2)advanced oxidation process(AOP),as well as the formation of bromate were investigated at different temperatures and pH values.Complete removal of gemfibrozil and a maximum of 80%ibuprofen removal were achieved using ozone dosage of 1.5 mg/L with O3:H2O2 ratio of 1:0.25 in the O3/H2O2 process.The effect of temperature on the removal efficiency of these two compounds was found to be negligible from 25 to 40ᵒC for both processes.pH effect from 6 to 9 was also found to be negligible for gemfibrozil removal,while ibuprofen had relatively lower removal by ozonation at pH 6 compared to higher pH values.Bromate formation was decreased to 0.012 mg/L when the pH was increased to 9.Increasing the temperature to 40ᵒC also resulted in less bromate formation which was the lowest value obtained in this study at 0.0102 mg/L.Addition of H2O2 did not affect the formation of bromate and in some cases it was found to be slightly higher compared with ozonation treatment.
基金supported by the National Science Foundations of China(No.61905256)the National Key Research and Development Program of China(No.2019YFC0214702)the Youth Innovation Promotion Association of Chinese Academy of Sciences(No.2020439)。
文摘This study describes the use of the weighted multiplicative algebraic reconstruction technique(WMART)to obtain vertical ozone profiles from limb observations performed by the scanning imaging absorption spectrometer for atmospheric chartography(SCIAMACHY).This technique is based on SaskMART(the combination of the multiplicative algebraic reconstruction technique and SaskTRAN radiative transfer model),which was originally developed for optical spectrometer and infrared imaging system(OSIRIS)data.One of the objectives of this study was to obtain consistent ozone profiles from the two satellites.In this study,the WMART algorithm is combined with a radiative transfer model(SCIATRAN),as well as a set of measurement vectors comprising five Hartley pairing vectors(HPVs)and one Chappuis triplet vector(CTV),to retrieve ozone profiles in the altitude range of 10–69 km.Considering that the weighting factors in WMART have a significant effect on the retrievals,we propose a novel approach to calculate the pair/triplet weighting factors using wavelength weighting functions.The results of the application of the proposed ozone retrieval scheme are compared with the SCIAMACHY v3.5 ozone product by University of Bremen and validated against profiles derived from other passive satellite observations or measured by ozonesondes.Between 18 and 55 km,the retrieved ozone profiles typically agree with data from the SCIAMACHY ozone product within 5%for tropics and middle latitudes,whereas a negative deviation exists between 35 and 50 km for northern high latitudes,with a deviation of less than 10%above 50 km.Comparison of the retrieved profiles with microwave limb sounder(MLS)v5.0 indicates that the difference is within±5%between 18 and 55 km,and an agreement within 10%is achieved in other altitudes for tropics and middle latitudes.Comparison of the retrieved profiles with OSIRIS v7.1 indicates that the average deviation is within±5%between 20 and 59 km,and difference of approximately 10%is achieved below 20 km.Compared with ozonesondes data,a general validity of the retrievals is no more than 5%between 15 and 30 km.
文摘Jeanologia,the global leader in sustainable textile technologies,is transforming textile finishing into a faster,cleaner,and more competitive process through its ground-breaking laser and ozone innovations.Technology at the core:Laser and Ozone The company's technological portfolio is led by two key solutions that are redefining industrial finishing.Laser Technology(exemplified by the Compact Super Flash system)delivers creativity,safety,quality,and natural aesthetics.It eliminates manual scraping,PP spray,and any hand touch,ensuring operator safety while boosting produc-tivity through automation and digital efficiency.It provides the best cost per garment and unparalleled design precision.
基金supported by the National Natural Science Foundation of China(Nos.U19A2044,42105132,42030609,41975037)the National Key Research and Development Programof China(No.2022YFC3700303).
文摘The Yangtze River Delta(YRD)region has witnessed a consistent decrease in NO_(2),CO,and PM_(2.5) from 2016 to 2023.However,ozone has exhibited fluctuating patterns.Quantifying ozone contributions from emissions,both within and outside the YRD,is essential for understanding city-cluster-scale ozone pollution(CCSOP).To address these concerns,a comprehensive approach combining Kolmogorov-Zurbenko filtering,Empirical Orthogonal Function,Absolute Principal Component Score,andMultiple Linear Regression methods(KZ-EOF-APCs-MLR)was employed to quantify the impacts of meteorological factors,local and non-local emission contributions of ozone(LECO and NECO).Emission changes were identified as the predominant factor shaping annual fluctuations in ambient ozone.Notably,during the previous andmiddle stages of the COVID-19 pandemic(from2017 to 2021),emissions reductions led to a marked decrease in YRD ozone levels(-7.01μg/m^(3)),with a pronounced rebound post-pandemic(2022 to 2023)(+8.04μg/m^(3)).Seasonally,the emissioninduced ozone exhibited fluctuating upward trend during autumn and winter,suggesting a transition of ozone pollution towards colder seasons.Spatially,high LECO concentrated in the eastern YRD(EYRD)across spring,autumn,and winter,becoming prominent in the central YRD(CYRD)during summer.During CCSOP,the CYRD exhibited the highest LECO and exceedance frequency(20.82μg/m^(3) and 45.27%).LECO explained a large portion of ozone variability during CCSOP,particularly in the EYRD,while NECO showed less explanatory power but consistently high contributions(148.05±15.52μg/m^(3)).These findings offer valuable insights for a deeper understanding of the evolving patterns of ozone pollution and the issue of CCSOP in the YRD.
基金supported by the National Natural Science Foundation of China(NSFC)(No.42107299).
文摘To better understand the effects of ground-level ozone(O_(3))on nutrients and stoichiometry in different plant organs,urban tree species Celtis sinensis,Cyclocarya paliu-rus,Quercus acutissima,and Quercus nuttallii were sub-jected to a constant exposure to charcoal-filtered air(CF),nonfiltered air(NF),or NF+40,60,or 80 nmol O_(3)mol^(-1)(NF40,NF60,and NF80)starting early in the summer of the growing season.At the end of summer,net CO_(2)assimila-tion rate(A),stomatal conductance(gs),leaf mass per area(LMA),and/or leaf greenness(SPAD)either were not sig-nificantly affected by elevated O_(3)or were even higher in some cases during the summer compared with the CF or NF controls.LMA was significantly lower in autumn only after the highest O_(3)exposures.Compared to NF,NF40 caused a large increase in gs across species in late summer and more K and Mn in stems.At the end of the growing season,nutri-ent status and stoichiometric ratios in different organs were variously altered under O_(3)stress;many changes were large and often species-specific.Across O_(3)treatments,LMA was primarily associated with C and Mg levels in leaves and Ca levels in leaves and stems.NF40 enriched K,P,Fe,and Mn in stems,relative to NF,and NF60 enhanced Ca in leaves relative to CF and NF40.Moreover,NF resulted in a higher Ca/Mg ratio in leaves of Q.acutissima only,relative to the other O_(3)regimes.Interestingly,across species,O_(3)stress led to different nutrient modifications in different organs(stems+branches vs leaves).Thus,ambient and/or elevated O_(3)exposures can alter the dynamics and distribution of nutrients and disrupt stoichiometry in different organs in a species-specific manner.Changes in stoichiometry reflect an important defense mechanism in plants under O_(3),and O_(3)pollution adds more risk to ecological stoichiometries in urban areas.
基金Supported by Hospital-level Project of Shiyan Taihe Hospital(2017JJXM091).
文摘[Objectives]To investigate the clinical efficacy of duloxetine combined with ozone pain point injection for the treatment of fibromyalgia(FM)and assess the effects of this combination therapy on pain,depression,and sleep disorders.[Methods]A randomized controlled crossover design was employed in this study.Sixty inpatients diagnosed with FM were allocated into three groups:the duloxetine group,the ozone group,and the combination therapy group,with each group consisting of 20 participants.The treatment duration was set at 4 weeks.The Visual Analogue Scale(VAS),the Fibromyalgia Impact Questionnaire(FIQ),the Hamilton Depression Scale(HAMD),the Pittsburgh Sleep Quality Index(PSQI),and the number of tender points were assessed prior to treatment,2 weeks post treatment,and 4 weeks post treatment.[Results]There were no statistically significant differences in various indicators among the three groups of patients prior to treatment.Following treatment,the VAS,FIQ,HAMD,PSQI,and the number of tender points in all three groups exhibited significant improvements(P<0.05).Notably,the combination therapy group demonstrated the most substantial reductions in each score,surpassing the improvements observed in the single application group(P<0.05).[Conclusions]Duloxetine combined with ozone pain point injection demonstrates a synergistic effect in alleviating pain,reducing depression,and enhancing sleep quality in patients with FM.This combination therapy exhibits superior efficacy compared to monotherapy and holds significant potential for clinical application.
基金supported by the National Natural Science Foundation of China(Grant No.91744311).
文摘We used observed concentrations of air pollutants,reanalyzed meteorological parameters,and results from the Goddard Earth Observing System Chemical Transport Model to examine the relationships between concentrations of maximum daily 8-h average ozone(MDA8 O_(3)),PM_(2.5)(particulate matter with diameter of 2.5μm or less),and PM_(2.5)components and 2-m temperature(T2)or relative humidity(RH),as well as the effectiveness of precursor emission reductions on the control of O_(3) and PM_(2.5) in Beijing–Tianjin–Hebei(BTH)under different summertime temperature and humidity conditions.Both observed(simulated)MDA8 O_(3) and PM_(2.5) concentrations increased as T2 went up,with linear trends of 4.8(3.2)ppb℃^(−1) and 1.9(1.5)μg m^(−3)℃^(−1),respectively.Model results showed that the decreases in MDA8 O_(3) from precursor emission reductions were more sensitive to T2 than to RH.Reducing a larger proportion of volatile organic compound(VOC)emissions at higher T2 was more effective for the control of summertime O_(3) in BTH.For the control of summertime PM_(2.5) in BTH,reducing nitrogen oxides(NOx)combined with a small proportion of VOCs was the best measure.The magnitude of reduction in PM_(2.5) from reducing precursor emissions was more sensitive to RH than to T2,with the best efficiency at high RH.Results from this study are helpful for formulating effective policies to tackle O_(3) and PM_(2.5) pollution in BTH.
基金supported by the National Natural Science Foundation of China(Nos.62275250 and 61905003)the Natural Science Foundation of Anhui Province(No.2008085J20)+1 种基金the National Key R&D Program of China(No.2022YFC3700301)Anhui Provincial Key R&D Program(No.2022l07020022).
文摘A novel system for measuring net photochemical ozone production rates in the atmosphere based on cavity ring-down spectroscopy(OPR-CRDS)was developed.The system consists of two chambers(a reaction chamber and a reference chamber)and a dual-channel O_(x)-CRDS detector.To minimize the wall loss of O_(x)in the chambers,the inner surfaces of both chambers are coated with Teflon film.The performance of the OPR-CRDS system was characterized.It was found that even though the photolysis frequency(J value)decreased by 10%,the decrease in the P(O_(3))caused by the ultraviolet-blocking film coating was less than 3%.The two chambers had a good consistency in the mean residence time and the measurement of NO_(2)and O_(x)under the condition of no sunlight.The detection limit of the OPR-CRDS was determined to be 0.20 ppbv/hr.To further verify the accuracy of the system,the direct measurement values of the OPR-CRDS systemwere comparedwith the calculation results based on radical(OH,HO_(2),and RO_(2))reactions,and a good correlation was obtained between the measured and calculated values.Finally,the developed instrument was applied to obtain the comprehensive field observations at an urban site in the Yangtze River Delta(China)for 40 days,the time series and change characteristics of the P(O_(3))were obtained directly,and the good environmental adaptability and stability of the OPR-CRDS system were demonstrated.It is expected that the new instrument will be beneficial to investigations of the relationship between P(O_(3))and its precursors.
基金financial support of the National Natural Science Foundation of China(Grant Nos.42122037,42375070 and 42275084)。
文摘Due to the control of ozone(O_(3))-depleting substances(ODSs),it is believed that stratospheric O_(3)will recover in the future.However,in the context of global change,the contributions of other factors to O_(3)recovery are also worth discussing.This paper investigates the independent and joint influences of changes in global methane(CH_(4)),carbon dioxide(CO_(2))and sea surface temperature(SST)on stratospheric O_(3)under the Representative Concentration Pathway(RCP)8.5 scenario in 2050 using sensitivity experiments with the Whole Atmosphere Community Climate Model,version4.Results show that,in the polar lower stratosphere,CH_(4)can reduce ODSs via chemical processes and further increase stratospheric O_(3)and temperature,which tends to reduce polar stratospheric clouds.This acts as positive feedback to O_(3)recovery.The increase of CH_(4)in the sensitivity experiments(CH_(4)is adjusted to match the 2050 levels under the RCP8.5scenario)could lead to a polar O_(3)recovery of about 27.9 DU in the Arctic.Increased CO_(2)(CO_(2) is adjusted to match the 2050 levels under the RCP8.5 scenario)can indirectly lead to a 6.5 DU increase in global total column O_(3)(TCO)through radiative effects,while the influence of SST on TCO in tropical regions can reach-3.3%.For the joint impact of CH_(4),CO_(2)and SST changes,CH_(4)can account for up to 69.0%of the TCO variations in the Antarctic region.Finally,we compare the effects of CH_(4)and ODSs on O_(3)in the polar regions in future experiments based on the RCP8.5 scenario.We find that ODSs are a dominant factor in O_(3)depletion in both poles;however,after 2040,the influence of increased CH_(4)on O_(3)recovery in the Arctic will surpass the effect of decreased ODSs.It implies that the future increase in CH_(4)may have an important impact on O_(3).
基金supported by the National Natural Science Foundation of China(No.31950410547 and 42107270).
文摘Ozone(O_(3))pollution has elevated in China,threatening plants and crop production.Ethylenediurea(EDU)is a chemical alleviating O_(3)-induced phytotoxicities.This study aimed at revealing fluctuating O_(3) exposures effects on Youxian No 3(Phaseolus vulgaris)and Sukui No 4(Vigna angularis),two widely grown Chinese bean cultivars,and EDU role in mediating these effects.Plants were periodically treated with EDU(400 mg/L)or water and subjected to charcoal-filtered air(CF)or non-filtered ambient air enriched with an additional targeted O_(3) concentration of 40 ppb(NF40).with subsequent ambient or NF40 exposures.A 10-day exposure to NF40 increased photosynthetic rate(A)while decreasing the leaf intercellular CO_(2) concentration(Ci),but this effect was absent after moving plants to ambient air for two weeks.Moving previously CF-exposed plants to ambient air for two weeks also increased A,which was not linked with Ci but more related to stomatal conductance(gs).Following two one-week and two-week sequential exposures of all plants to NF40,with an intermediate exposure to ambient air,elevated O_(3) reduced chlorophylls(SPAD),A,gs,Ci,and transpiration and decoupled A-gs response.More O_(3) effectswere observed in plants treatedwithNF40 during each O_(3)-treatment cycle,compared to those exposed to CF during the first cycle.The former plants exhibited significantly decreased biomass and water content of leaves and stems but increased flowers biomass and water content.Some of the effects were cultivardependent,with Youxian showing more apparent trade-offs between vegetative growth and reproduction.EDU alleviated various negative O_(3) effects.
基金supported by the National Natural Science Foundation of China(No.22278202).
文摘For the effective treatment of the wastewater with low-medium concentration ammonia nitrogen and low strength COD,a high-performance Co_(3)O_(4) catalyst supported on carbon nanocages(CNCs)was prepared.By isovolumetric im pregnation,Co_(3)O_(4) could be uniformly dispersed on surface of CNCs,which possess tiny particle size and strong electron transfer capability.The catalytic performance of the prepared Co_(3)O_(4)/CNCs catalysts with different Co_(3)O_(4) loadings was systematically evaluated and compared with Co_(3)O_(4)/CNTs.It is found that 20 wt.%Co_(3)O_(4)/CNCs shows the best catalytic performance,achieving an ammonia nitrogen conversion rate of 71.0%and a nitrogen selectivity of 81.8%.Compared to commonly used Co_(3)O_(4),ammonia conversion and nitrogen selectivity of Co_(3)O_(4)/CNCs increased by 28.9%and 15.8%respectively.In the five consecutive cycles,the catalytic activity remained stable.The mechanism that CNCs support effectively increases the surface oxygen vacancies of Co_(3)O_(4) through XPS analysis was also elucidated,and DFT calculations confirm strong electron transfer between CNCs and Co_(3)O_(4),rendering Co_(3)O_(4) nanoparticles as the primary catalytic active sites.The results may contribute to the development of highperformance catalytic ozone oxidation catalysts for ammonia nitrogen.
