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
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
Publisher Correction to:Journal of Forestry Research(2025)36:29 https://doi.org/10.1007/s11676-025-01823-0 In Fig.4c of this article,the lower part of the figure was unintentionally cropped and incomplete during the p...Publisher Correction to:Journal of Forestry Research(2025)36:29 https://doi.org/10.1007/s11676-025-01823-0 In Fig.4c of this article,the lower part of the figure was unintentionally cropped and incomplete during the publisher's production process.The published incorrect version and the corrected version of Fig.4 are given below.展开更多
The cardiopulmonary health of children may be affected by acute ozone(O3)exposure during physical activity[1];however,its effects in high-altitude regions such as the Xizang Plateau remain uncertain.In high-altitude a...The cardiopulmonary health of children may be affected by acute ozone(O3)exposure during physical activity[1];however,its effects in high-altitude regions such as the Xizang Plateau remain uncertain.In high-altitude areas,lower oxygen levels may cause children to experience shortness of breath or require increased respiratory effort during vigorous activities such as running.This could lead to increased pollutant inhalation,potentially elevating the burden on the cardiovascular system and triggering adverse reactions such as increased heart rate and elevated blood pressure.Furthermore,differences in physiological adaptation between Han children who have migrated to Xizang and Tibetan children who are native to the region may contribute to different reactions to environmental exposure[2].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
Cupressus sempervirens is a relevant species in the Mediterranean for its cultural,economic and landscape value.This species is threatened by Seiridium cardinale,the causal agent of the cypress canker disease(CCD).The...Cupressus sempervirens is a relevant species in the Mediterranean for its cultural,economic and landscape value.This species is threatened by Seiridium cardinale,the causal agent of the cypress canker disease(CCD).The effects of biotic stressors on O_(3)risk assessment are unknown and a comprehensive O_(3)risk assessment in C.sempervirens is missing.To fill these gaps,two clones of C.sempervirens,one resistant(Clone R)and one susceptible to CCD(Clone S),were subjected to three levels of O_(3)(Ambient Air-AA;1.5×AA;2.0×AA)for two consecutive years in an O_(3)-free-air controlled exposure facility and artificially inoculated with S.cardinale.Both the exposure-(AOT40)and flux-based(PODy)indices were tested.We found that PODy performed better than AOT40 to assess O_(3)effects on biomass and the critical level for a 4%biomass loss was 2.51 mmol/m^(2)POD2.However,significant O_(3)dose-response relationships were not found for the inoculated cypresses because the combination of middle level O_(3)(1.5×AA)and inoculation stimulated a biomass growth in Clone S as hormetic response.Moreover,we found a different inter-clonal response to both stressors with a statistically significant reduction of total and belowground biomass following O_(3),and lower root biomass in Clone S than in Clone R following pathogen infection.In summary,Clone R was more resistant to O_(3),and inoculation altered O_(3)risk via an hormetic effect on biomass.These results warrant further studies on how biotic stressors affect O_(3)responses and risk assessment.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
In recent years,ozone has become one of the key pollutants affecting the urban air qual-ity.Direct catalytic decomposition of ozone emerges as an effective method for ozone re-moval.Field experimentswere conducted to ...In recent years,ozone has become one of the key pollutants affecting the urban air qual-ity.Direct catalytic decomposition of ozone emerges as an effective method for ozone re-moval.Field experimentswere conducted to evaluate the effectiveness of exteriorwall coat-ings with ozone decomposition catalysts for ozone removal in practical applications.ANSYS 2020R1 software was first used for simulation and analysis of ozone concentration and flow fields to investigate the decomposition boundary of these wall coatings.The results show that the exterior wall coatings with manganese-based catalysts can effectively reduce the ozone concentration near the wall coating.The ozone decomposition efficiency is nega-tively correlated with the distance fromthe coating and the decomposition boundary range is around 18 m.The decomposition boundary will increase with the increase of tempera-ture,and decrease with the increase of the wind speed and the relative humidity.These results underscore the viability of using exterior wall coatings with catalysts for controlling ozone pollution in atmospheric environments.This approach presents a promising avenue for addressing ozone pollution through self-purifying materials on building external wall.展开更多
The North China Plain(NCP)frequently experiences ozone pollution events,which are generally related to cross-border transport at multiple scales.However,current methods of calculating ozone transport are insufficient ...The North China Plain(NCP)frequently experiences ozone pollution events,which are generally related to cross-border transport at multiple scales.However,current methods of calculating ozone transport are insufficient to account for ozone transport at different altitudes.To further understand the characteristics of ozone transport,we applied theWeather Research and Forecasting(WRF)model and the Comprehensive Air Quality Model with Extensions(CAMx)based on flux calculation method.The results showed that the simulated flux calculation method was suitable for revealing the evolutionary trend of ozone fluxes.Monthly inflows,outflows,and total net fluxes ranged from-32985.45 to 37361.46 t/d and indicated strong transport and significant spatial and temporal variations of ozone in the urban boundary segments.Vertical distribution analysis of the net ozone fluxes demonstrated that the net fluxes varied with the altitude,and the altitude at which the corresponding peaks were located had a strong correlation with the neighborhood and season.It was noteworthy that there were three main transport directions throughout the year,namely northwest-southeast(NW-SE),southeast-northwest(SE-NW),and southwestnortheast(SW-NE).Additionally,the ozone flux was mainly affected by temperature,wind speed,and ozone concentration,with the correlation coefficient varying by season and altitude,up to 0.78.Moreover,the correlation analysis of ozone flux and wind direction in each city further verified the accuracy of the transport direction.This paper can provide scientific and technological support for the study of ozone generation mechanisms and the solution of urban/interregional ozone pollution problems.展开更多
The ozone over the Tibetan Plateau(TP)plays an important role in protecting the local ecology by absorbing ultraviolet solar rays.The El Nino-Southern Oscillation(ENSO),recognized as the strongest interannual climate ...The ozone over the Tibetan Plateau(TP)plays an important role in protecting the local ecology by absorbing ultraviolet solar rays.The El Nino-Southern Oscillation(ENSO),recognized as the strongest interannual climate phenomenon globally,can create ozone variations over the TP.Based on the historical experimental simulation results of two Community Earth System Models(i.e.CESM2-WACCM and CESM2-WACCM-FV2)that include the coupling process of stratospheric chemistry-radiation-dynamics,this study analyzes the impact of ENSO on the wintertime total ozone column(TCO)over the TP,as well as its physical processes,from 1979 to 2014.When compared to observations,the results show that the two models can basically simulate the spatial distribution of the climate state and standard deviation of the TP TCO.In the two models,CESM2-WACCM performs better.During the winter when the ENSO signal is strongest,its warm phase,El Nino,cools the tropospheric temperature over the TP by modifying the atmospheric circulation,which induces a decrease in the tropopause height.Such decreases in the tropopause height are responsible for the TP TCO increase.The cool phase La Nina is responsible for a TCO decrease over the TP,in a manner resembling the El Nino but with the opposite signal.Our results are consistent with previous observational analysis,and the relevant research provides valuable scientific insights for evaluating and improving the Earth System Model that incorporates the coupling process of stratospheric chemistry-radiation-dynamics.展开更多
Acetaldehyde plays a significant role in atmospheric photochemical reactions and ozone formation.Previous studies have shown that acetaldehyde may rapidly be generated over short periods and impact ozone production,ye...Acetaldehyde plays a significant role in atmospheric photochemical reactions and ozone formation.Previous studies have shown that acetaldehyde may rapidly be generated over short periods and impact ozone production,yet the underlyingmechanism remains unclear.To better elucidate thesemechanisms,a field campaign was conducted in Dongying,a typical petrochemical city in China.The observed acetaldehyde concentration averaged 3.0±1.6 ppbv,with a peak around 09:00 local time.The diurnal variations of acetaldehyde were categorized into two types,with Category 1 exhibiting relatively high values and increasing sharply in concentration between 07:00 and 09:00 a.m.(refer to morning peak episode,MPE),and the remaining classified as Category 2.Category 1 was similar to previous studies at heavily polluted sites but differed fromcleaner locations.Using an observation-based chemical box model,we found that acetaldehyde contributed an average of 10.2%to the net ozone production rate.Combined with a positive matrix factorizationmodel,we identified secondary formation as the dominant source of acetaldehyde(45.0%),and the daytime production rate of acetaldehyde in Category 1 was significantly higher than that in Category 2.Cis-2-butene and trans-2-butene were identified as key precursors for the rapid acetaldehyde formation during the MEP,with the petroleum industry being their primary source.Volatile organic compounds(VOCs)from petroleum industry contributed over 60%to acetaldehyde formation during the morning peak.Our findings underscore the urgent need for targeted VOCs management strategies in petroleum sector tomitigate both carbonyl and ozone formation.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
Serious fine particulate matter(PM_(2.5))pollution and rapidly increasing of ground-level ozone(O_(3))concentrations are concern issues in China.To achieve the comprehensive control of PM_(2.5)-O_(3) composite air pol...Serious fine particulate matter(PM_(2.5))pollution and rapidly increasing of ground-level ozone(O_(3))concentrations are concern issues in China.To achieve the comprehensive control of PM_(2.5)-O_(3) composite air pollution,exploring the common sources of PM_(2.5) and VOCs is essential.However,previous researches most carried out either PM_(2.5) or VOCs source appointment.In this study,we applied the ensemble source apportionment method to explore the impacts of common sources on PM_(2.5)-VOCs.Subsequently,we obtained the ensemble source impacts on O_(3) combining the extracted VOCs source profile and ozone formation potential.We found that the focus of environmentalmanagement and source control should be varied accordingly for different pollutants.Vehicle emission was the largest contributor(41%)to PM_(2.5)-VOCs,while industrial emission was the main common source(51%)to O_(3).The result showed that the O_(3) production rate is not only related to the VOCs emission,but also to the reactivity of VOCs.In addition,sensitivity tests revealed that temperature was the main factor affecting O_(3) formation.The study provides a framework to explore the common sources impact on PM_(2.5) and VOCs,which is benefit to address both PM_(2.5) and O_(3) mitigations.展开更多
Post-etching method using dilute acid solutions is an effective technology to modulate the surface compositions of metal-oxide catalysts.Here theα-MnO_(2) catalyst treated with 0.1 mol/L nitric acid exhibits higher o...Post-etching method using dilute acid solutions is an effective technology to modulate the surface compositions of metal-oxide catalysts.Here theα-MnO_(2) catalyst treated with 0.1 mol/L nitric acid exhibits higher ozone decomposition activity at high relative humidity than the counterpart treated with acetic acid.Besides the increases in surface area and lattice dislocation,the improved activity can be due to relatively higher Mn valence on the surface and newly-formed Brønsted acid sites adjacent to oxygen vacancies.The remnant nitro species deposited on the catalyst by nitric acid treatment is ideal hydrophobic groups at ambient conditions.The decomposition route is also proposed based on the DRIFTS and DFT calculations:ozone is facile to adsorb on the oxygen vacancy,and the protonic H of Brønsted acid sites bonds to the terminal oxygen of ozone to accelerate its cleavage to O_(2),reducing the reaction energy barrier of O_(2) desorption.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
Tropospheric ozone pollution has been worsened over most regions of China,adversely affecting human health and ecosystems.The long-term ozone concentration depends largely upon atmospheric circulations.Here,we conduct...Tropospheric ozone pollution has been worsened over most regions of China,adversely affecting human health and ecosystems.The long-term ozone concentration depends largely upon atmospheric circulations.Here,we conducted meteorological adjustment to quantitatively assess the influences of meteorological factors on the ozone evolution in China's seven city clusters during thewarm season(April to October)from 2013 to 2020.Our analysis indicated that northern and eastern regions experienced ozone increases driven by emission changes.Southern regions,particularly the Pearl River Delta(PRD),exhibited ozone rise primarily due to meteorological conditions despite emission changes.In the Sichuan Basin(SCB)and Central Yangtze River Plain(CYP),where ozone levels decreased,meteorological conditions played a significant role in suppressing the ascent of ozone.Empirical orthogonal functions(EOF)analyses suggested that the spatiotemporal trend ofmeteorologyassociated ozone was strongly correlated with the variation of East Asian Trough(EAT),South Asian High(SAH)and the western Pacific subtropical high(WPSH).The top three EOF patterns explained 33.4%,21.8%,and 16.0%of the total variance inmeteorology-associated ozone.Absolute principal component scores-multiple linear regression(APCS-MLR)analyse quantitatively identified that enhanced EAT and SAH with a northward location of WPSH were favourable to surface ozone formation in central and eastern regions,but unfavourable to ozone formation in edge regions such as SCB.展开更多
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 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Publisher Correction to:Journal of Forestry Research(2025)36:29 https://doi.org/10.1007/s11676-025-01823-0 In Fig.4c of this article,the lower part of the figure was unintentionally cropped and incomplete during the publisher's production process.The published incorrect version and the corrected version of Fig.4 are given below.
基金supported by the National Key Research and Development Program of China(grant number 2022YFC3702604)National Natural Science Foundation of China(41977374).
文摘The cardiopulmonary health of children may be affected by acute ozone(O3)exposure during physical activity[1];however,its effects in high-altitude regions such as the Xizang Plateau remain uncertain.In high-altitude areas,lower oxygen levels may cause children to experience shortness of breath or require increased respiratory effort during vigorous activities such as running.This could lead to increased pollutant inhalation,potentially elevating the burden on the cardiovascular system and triggering adverse reactions such as increased heart rate and elevated blood pressure.Furthermore,differences in physiological adaptation between Han children who have migrated to Xizang and Tibetan children who are native to the region may contribute to different reactions to environmental exposure[2].
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 the Italian Integrated Environmental Research Infrastructures Systems(ITINERIS)(Nos.IR0000032 and CUP B53C22002150006).
文摘Cupressus sempervirens is a relevant species in the Mediterranean for its cultural,economic and landscape value.This species is threatened by Seiridium cardinale,the causal agent of the cypress canker disease(CCD).The effects of biotic stressors on O_(3)risk assessment are unknown and a comprehensive O_(3)risk assessment in C.sempervirens is missing.To fill these gaps,two clones of C.sempervirens,one resistant(Clone R)and one susceptible to CCD(Clone S),were subjected to three levels of O_(3)(Ambient Air-AA;1.5×AA;2.0×AA)for two consecutive years in an O_(3)-free-air controlled exposure facility and artificially inoculated with S.cardinale.Both the exposure-(AOT40)and flux-based(PODy)indices were tested.We found that PODy performed better than AOT40 to assess O_(3)effects on biomass and the critical level for a 4%biomass loss was 2.51 mmol/m^(2)POD2.However,significant O_(3)dose-response relationships were not found for the inoculated cypresses because the combination of middle level O_(3)(1.5×AA)and inoculation stimulated a biomass growth in Clone S as hormetic response.Moreover,we found a different inter-clonal response to both stressors with a statistically significant reduction of total and belowground biomass following O_(3),and lower root biomass in Clone S than in Clone R following pathogen infection.In summary,Clone R was more resistant to O_(3),and inoculation altered O_(3)risk via an hormetic effect on biomass.These results warrant further studies on how biotic stressors affect O_(3)responses and risk assessment.
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(Nos.52470114 and 52022104)the National Key R&D Program of China(No.2022YFC3702802)the Youth Innovation Promotion Association,CAS(No.Y2021020).
文摘In recent years,ozone has become one of the key pollutants affecting the urban air qual-ity.Direct catalytic decomposition of ozone emerges as an effective method for ozone re-moval.Field experimentswere conducted to evaluate the effectiveness of exteriorwall coat-ings with ozone decomposition catalysts for ozone removal in practical applications.ANSYS 2020R1 software was first used for simulation and analysis of ozone concentration and flow fields to investigate the decomposition boundary of these wall coatings.The results show that the exterior wall coatings with manganese-based catalysts can effectively reduce the ozone concentration near the wall coating.The ozone decomposition efficiency is nega-tively correlated with the distance fromthe coating and the decomposition boundary range is around 18 m.The decomposition boundary will increase with the increase of tempera-ture,and decrease with the increase of the wind speed and the relative humidity.These results underscore the viability of using exterior wall coatings with catalysts for controlling ozone pollution in atmospheric environments.This approach presents a promising avenue for addressing ozone pollution through self-purifying materials on building external wall.
基金supported by the National Natural Science Foundation of China(No.52200120)the R&D Program of Beijing Municipal Education Commission(No.KM202310011003)。
文摘The North China Plain(NCP)frequently experiences ozone pollution events,which are generally related to cross-border transport at multiple scales.However,current methods of calculating ozone transport are insufficient to account for ozone transport at different altitudes.To further understand the characteristics of ozone transport,we applied theWeather Research and Forecasting(WRF)model and the Comprehensive Air Quality Model with Extensions(CAMx)based on flux calculation method.The results showed that the simulated flux calculation method was suitable for revealing the evolutionary trend of ozone fluxes.Monthly inflows,outflows,and total net fluxes ranged from-32985.45 to 37361.46 t/d and indicated strong transport and significant spatial and temporal variations of ozone in the urban boundary segments.Vertical distribution analysis of the net ozone fluxes demonstrated that the net fluxes varied with the altitude,and the altitude at which the corresponding peaks were located had a strong correlation with the neighborhood and season.It was noteworthy that there were three main transport directions throughout the year,namely northwest-southeast(NW-SE),southeast-northwest(SE-NW),and southwestnortheast(SW-NE).Additionally,the ozone flux was mainly affected by temperature,wind speed,and ozone concentration,with the correlation coefficient varying by season and altitude,up to 0.78.Moreover,the correlation analysis of ozone flux and wind direction in each city further verified the accuracy of the transport direction.This paper can provide scientific and technological support for the study of ozone generation mechanisms and the solution of urban/interregional ozone pollution problems.
基金jointly supported by the National Natural Science Foundation of China(grant Nos.U2442210,42175042,42275059)the Natural Science Foundation of Sichuan Province(grant Nos.2024NSFTD0017,2023NSFSC0246)the Second Tibetan Plateau Scientific Expedition and Research(STEP)program(2019QZKK0103)。
文摘The ozone over the Tibetan Plateau(TP)plays an important role in protecting the local ecology by absorbing ultraviolet solar rays.The El Nino-Southern Oscillation(ENSO),recognized as the strongest interannual climate phenomenon globally,can create ozone variations over the TP.Based on the historical experimental simulation results of two Community Earth System Models(i.e.CESM2-WACCM and CESM2-WACCM-FV2)that include the coupling process of stratospheric chemistry-radiation-dynamics,this study analyzes the impact of ENSO on the wintertime total ozone column(TCO)over the TP,as well as its physical processes,from 1979 to 2014.When compared to observations,the results show that the two models can basically simulate the spatial distribution of the climate state and standard deviation of the TP TCO.In the two models,CESM2-WACCM performs better.During the winter when the ENSO signal is strongest,its warm phase,El Nino,cools the tropospheric temperature over the TP by modifying the atmospheric circulation,which induces a decrease in the tropopause height.Such decreases in the tropopause height are responsible for the TP TCO increase.The cool phase La Nina is responsible for a TCO decrease over the TP,in a manner resembling the El Nino but with the opposite signal.Our results are consistent with previous observational analysis,and the relevant research provides valuable scientific insights for evaluating and improving the Earth System Model that incorporates the coupling process of stratospheric chemistry-radiation-dynamics.
基金supported by the National Key Research and Development Program of the Ministry of Science of Technology of China(No.2022YFC3701101)the National Natural Science Foundation of China(No.42105106)+2 种基金China Postdoctoral Science Foundation(No.2021M691921)the Ministry of Ecology and Environment of the People’s Republic of China(No.DQGG202121)Dongying Ecological and Environmental Bureau(No.2021DFKY-0779).
文摘Acetaldehyde plays a significant role in atmospheric photochemical reactions and ozone formation.Previous studies have shown that acetaldehyde may rapidly be generated over short periods and impact ozone production,yet the underlyingmechanism remains unclear.To better elucidate thesemechanisms,a field campaign was conducted in Dongying,a typical petrochemical city in China.The observed acetaldehyde concentration averaged 3.0±1.6 ppbv,with a peak around 09:00 local time.The diurnal variations of acetaldehyde were categorized into two types,with Category 1 exhibiting relatively high values and increasing sharply in concentration between 07:00 and 09:00 a.m.(refer to morning peak episode,MPE),and the remaining classified as Category 2.Category 1 was similar to previous studies at heavily polluted sites but differed fromcleaner locations.Using an observation-based chemical box model,we found that acetaldehyde contributed an average of 10.2%to the net ozone production rate.Combined with a positive matrix factorizationmodel,we identified secondary formation as the dominant source of acetaldehyde(45.0%),and the daytime production rate of acetaldehyde in Category 1 was significantly higher than that in Category 2.Cis-2-butene and trans-2-butene were identified as key precursors for the rapid acetaldehyde formation during the MEP,with the petroleum industry being their primary source.Volatile organic compounds(VOCs)from petroleum industry contributed over 60%to acetaldehyde formation during the morning peak.Our findings underscore the urgent need for targeted VOCs management strategies in petroleum sector tomitigate both carbonyl and ozone formation.
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 Key Research and Development Program of China(Nos.2023YFC3709500,2023YFC3709502 and 2022YFC3703400)the National Natural Science Foundation of China(No.42077191)+1 种基金the Fundamental Research Funds for the Central Universities(No.63233054)Tianjin Science and Technology Plan Project(No.18PTZWHZ00120).
文摘Serious fine particulate matter(PM_(2.5))pollution and rapidly increasing of ground-level ozone(O_(3))concentrations are concern issues in China.To achieve the comprehensive control of PM_(2.5)-O_(3) composite air pollution,exploring the common sources of PM_(2.5) and VOCs is essential.However,previous researches most carried out either PM_(2.5) or VOCs source appointment.In this study,we applied the ensemble source apportionment method to explore the impacts of common sources on PM_(2.5)-VOCs.Subsequently,we obtained the ensemble source impacts on O_(3) combining the extracted VOCs source profile and ozone formation potential.We found that the focus of environmentalmanagement and source control should be varied accordingly for different pollutants.Vehicle emission was the largest contributor(41%)to PM_(2.5)-VOCs,while industrial emission was the main common source(51%)to O_(3).The result showed that the O_(3) production rate is not only related to the VOCs emission,but also to the reactivity of VOCs.In addition,sensitivity tests revealed that temperature was the main factor affecting O_(3) formation.The study provides a framework to explore the common sources impact on PM_(2.5) and VOCs,which is benefit to address both PM_(2.5) and O_(3) mitigations.
基金supported by the National Natural Science Foundation of China(Nos.22206155 and T2341002)the Fundamental Research Funds for the Central Universities of China(Nos.2682022CX035 and 2682022KJ035)+2 种基金China Postdoctoral Science Foundation(Nos.2022M712632 and 2023T160547)Sichuan Science and Technology Program(No.2023JDRC0066)the State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex(No.SCAPC202109).
文摘Post-etching method using dilute acid solutions is an effective technology to modulate the surface compositions of metal-oxide catalysts.Here theα-MnO_(2) catalyst treated with 0.1 mol/L nitric acid exhibits higher ozone decomposition activity at high relative humidity than the counterpart treated with acetic acid.Besides the increases in surface area and lattice dislocation,the improved activity can be due to relatively higher Mn valence on the surface and newly-formed Brønsted acid sites adjacent to oxygen vacancies.The remnant nitro species deposited on the catalyst by nitric acid treatment is ideal hydrophobic groups at ambient conditions.The decomposition route is also proposed based on the DRIFTS and DFT calculations:ozone is facile to adsorb on the oxygen vacancy,and the protonic H of Brønsted acid sites bonds to the terminal oxygen of ozone to accelerate its cleavage to O_(2),reducing the reaction energy barrier of O_(2) desorption.
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.42377095)the Open Research Fund Program of Plateau Atmosphere and Environment Key Laboratory of Sichuan Province(No.PAEKL-2024-K01)Xianyang Key Research and Development Program(No.L2022ZDYFSF040).
文摘Tropospheric ozone pollution has been worsened over most regions of China,adversely affecting human health and ecosystems.The long-term ozone concentration depends largely upon atmospheric circulations.Here,we conducted meteorological adjustment to quantitatively assess the influences of meteorological factors on the ozone evolution in China's seven city clusters during thewarm season(April to October)from 2013 to 2020.Our analysis indicated that northern and eastern regions experienced ozone increases driven by emission changes.Southern regions,particularly the Pearl River Delta(PRD),exhibited ozone rise primarily due to meteorological conditions despite emission changes.In the Sichuan Basin(SCB)and Central Yangtze River Plain(CYP),where ozone levels decreased,meteorological conditions played a significant role in suppressing the ascent of ozone.Empirical orthogonal functions(EOF)analyses suggested that the spatiotemporal trend ofmeteorologyassociated ozone was strongly correlated with the variation of East Asian Trough(EAT),South Asian High(SAH)and the western Pacific subtropical high(WPSH).The top three EOF patterns explained 33.4%,21.8%,and 16.0%of the total variance inmeteorology-associated ozone.Absolute principal component scores-multiple linear regression(APCS-MLR)analyse quantitatively identified that enhanced EAT and SAH with a northward location of WPSH were favourable to surface ozone formation in central and eastern regions,but unfavourable to ozone formation in edge regions such as SCB.
