The Nested Air Quality Prediction Model System(NAQPMS)was used to investigate the temporal and spatial variations of PM2.5over tropospheric central eastern China in January 2013.The impact of regional transport and it...The Nested Air Quality Prediction Model System(NAQPMS)was used to investigate the temporal and spatial variations of PM2.5over tropospheric central eastern China in January 2013.The impact of regional transport and its implications on pollution prevention and control were also examined.Comparison between simulated and observed PM2.5showed NAQPMS was able to reproduce the evolution of PM2.5during heavy haze episodes.The results indicated that regional transport of PM2.5played an important role in regional haze episodes in the city cluster including Hebei,Beijing and Tianjin(HBT).The cross-city clusters transport outside HBT and transport among cities inside HBT contributed 20%–35%and 26%–35%of PM2.5as compared with local emission,in HBT respectively.To meet the Air Quality Standards for Grade II,90%,90%and65%of emissions would have to be cut down in Hebei,Tianjin and Beijing,if non-control strategy was taken in the surrounding city clusters of HBT.This implicated that control of emissions in one city cluster is not sufficient to reduce regional haze events,and joint efforts among city clusters are essential.Besides regional transports,two-way feedback between boundary-layer evolution and PM2.5also significantly contributed to the formation of heavy hazes,which contributed 30%of monthly average PM2.5concentration in HBT.展开更多
Background:Corneal scarring following bacterial keratitis,particularly from Pseudomonas infections,poses significant challenges in ophthalmic care.Current treatments often fall short in effectively reducing corneal ha...Background:Corneal scarring following bacterial keratitis,particularly from Pseudomonas infections,poses significant challenges in ophthalmic care.Current treatments often fall short in effectively reducing corneal haze and restoring vision.To our knowledge,this is the first report documenting the use of topical losartan,an angiotensin II receptor antagonist known to inhibit the transforming growth factor-β(TGF-β)pathway,for treating corneal haze resulting from bacterial keratitis.Case Description:A 30-year-old male presented with a persistent corneal scar in his right eye,178 days post-Pseudomonas keratitis.Despite a prolonged course of topical corticosteroids,his best-corrected visual acuity(BCVA)stabilized at 20/40 with a hybrid contact lens over a 2-month period.Given the lack of improvement,we initiated treatment with topical losartan at a concentration of 0.8 mg/mL,administered six times daily.After 4 months of therapy,the patient’s BCVA improved to 20/25.Slit-lamp examination and corneal tomography revealed a significant reduction in corneal haze,indicating a positive response to the treatment.Conclusions:This case suggests that topical losartan may be a promising therapeutic option for reducing corneal opacity following bacterial keratitis by inhibiting the TGF-βpathway.However,further clinical studies are necessary to confirm its efficacy and safety in broader patient populations.展开更多
License plate recognition in haze-affected images is challenging due to feature distortions such as blurring and elongation,which lead to pixel displacements.This article introduces a Displacement Region Recognition M...License plate recognition in haze-affected images is challenging due to feature distortions such as blurring and elongation,which lead to pixel displacements.This article introduces a Displacement Region Recognition Method(DR2M)to address such a problem.This method operates on displaced features compared to the training input observed throughout definite time frames.The technique focuses on detecting features that remain relatively stable under haze,using a frame-based analysis to isolate edges minimally affected by visual noise.The edge detection failures are identified using a bilateral neural network through displaced feature training.The training converges bilaterally towards the minimum edges from the maximum region.Thus,the training input and detected edges are used to identify the displacement between observed image frames to extract and differentiate the license plate region from the other vehicle regions.The proposed method maps the similarity feature between the detected and identified vehicle regions.This aids in leveraging the plate recognition precision with a high F1 score.Thus,this technique achieves a 10.27%improvement in identification precision,a 10.57%increase in F1 score,and a 9.73%reduction in false positive rate compared to baseline methods under maximum displacement conditions caused by haze.The technique attains an identification precision of 95.68%,an F1 score of 94.68%,and a false positive rate of 4.32%,indicating robust performance under haze-affected settings.展开更多
The chemical composition of dew is closely related to the air quality.Since 2013,China has promulgated a series of laws and regulations focused on air pollution control,and remarkable results have been achieved over t...The chemical composition of dew is closely related to the air quality.Since 2013,China has promulgated a series of laws and regulations focused on air pollution control,and remarkable results have been achieved over the past decade.As an indicator of near-surface air quality,the chemical composition of dew obviously changes.The dew quality was affected mainly by the local air quality.The mean dew pH was 6.3±0.4(n=186)from 2013 to 2023,and the order of ions was SO_(4)^(2-)(3180.7±3592.0μeq/L)>NH_(4)^(+)(2552.3±2971.8μeq/L)>Ca^(2+)(1006.2±945.5μeq/L)>NO_(3)^(-)(397.2±511.0μeq/L)>Cl^(-)(152.3±133.4μeq/L)>K^(+)(149.4±191.6μeq/L)>F^(-)(133.0±110.3μeq/L)>Na^(+)(123.8±94.9μeq/L)>Mg^(2+)(83.3±65.6μeq/L).The dew quality deteriorated on hazy days.There were no haze events during the condensation period after 2020,which caused a significant reduction in the concentration of the main ions in the dew.Over the past decade,electrical conductivity(EC),total dissolved solids(TDS),PM_(2.5) and PM_(10),as well as major ions(SO_(4)^(2-),NO_(3)^(-),NH_(4)^(+),Ca^(2+),Cl^(-),Na^(+),F^(-),K^(+)and Mg^(2+))in dew,have all tended to decrease.The annualmean NO_(3)^(-)concentration in 2023 was 86.5%lower than that in 2013,with values of 79.3%for SO_(4)^(2-),77.3%for Ca^(2+),76.7%for NH_(4)^(+),74.6%for K^(+),65.4%for Mg^(2+),63.4%for Na^(+),61.7%for Cl^(-),and 60.3%for F^(-).展开更多
In this study,online water-soluble inorganic ions were detected to deduce the formation mechanism of secondary inorganic aerosol in Xianyang,China during wintertime.The dominant inorganic ions of sulfate(SO_(4)^(2-)),...In this study,online water-soluble inorganic ions were detected to deduce the formation mechanism of secondary inorganic aerosol in Xianyang,China during wintertime.The dominant inorganic ions of sulfate(SO_(4)^(2-)),nitrate(NO_(3)^(-)),and ammonium(NH_(4)^(+))(the sum of those is abbreviated as SNA)accounted for 17%,21%,and 12% of PM_(2.5)mass,respectively.While the air quality deteriorated from excellent to poor grades,the precursor gas sulfur dioxide(SO_(2))of SO_(4)^(2-)increased and then decreased with a fluctuation,while nitrogen dioxide(NO_(2))and ammonia(NH_(3)),precursors of NO_(3)^(-)and NH_(4)^(+),and SNA show increasing trends.Meteorological factors including boundary layer height(BLH),temperature,and wind speed also show decline trends,except relative humidity(RH).Meanwhile,the secondary conversion ratio shows a remarkable increasing trend,indicating that there was a strong secondary transformation.From the perspective of chemical mechanisms,RH is positively correlated with sulfur oxidation ratios(SOR),nitrogen oxidation ratios(NOR),and ammonia conversion ratios,representing that the increase of humidity could promote the generation of SNA.Notably,SOR and NOR were also positively related to the ammonia.On the one hand,the low wind speed and BLH led to the accumulation of pollutants.On the other hand,the increases of RH and ammonia promoted more formations of SNA and PM_(2.5).The results advance our identification of the contributors to the haze episodes and assist to establish more efficient emission controls in Xianyang,in addition to other cities with similar emission and geographical characteristics.展开更多
Sandstorm,which injects generous newly emerging microbes into the atmosphere covering cities,adversely affects the air quality in built environments.However,few studies have examined the change of airborne bacteria du...Sandstorm,which injects generous newly emerging microbes into the atmosphere covering cities,adversely affects the air quality in built environments.However,few studies have examined the change of airborne bacteria during severe sandstorm events.In this work,we analyzed the airborne bacteria during one of the strongest sandstorms in East Asia onMarch 15th,2021,which affected large areas of China and Mongolia.The characteristics of the sandstorm were compared with those of the subsequent clean and haze days.The composition of the bacterial community of air samples was investigated using quantitative polymerase chain reaction(qPCR)and high-throughput sequencing technology.During the sandstorm,the particulate matter(PM)concentration and bacterial richnesswere extremely high(PM_(2.5):207μg/m^(3);PM_(10):1630μg/m^(3);5700 amplicon sequence variants/m^(3)).In addition,the sandstorm brought 10 pathogenic bacterial genera to the atmosphere,posing a grave hazard to human health.As the sandstorm subsided,small bioaerosols(0.65–1.1μm)with a similar bacterial community remained suspended in the atmosphere,bringing possible long-lasting health risks.展开更多
Atmospheric carbonyl compounds play significant roles in the cycling of radicals and have exhibited surprisingly high levels in winter that were well correlated to particulate matter,for which the reason have not been...Atmospheric carbonyl compounds play significant roles in the cycling of radicals and have exhibited surprisingly high levels in winter that were well correlated to particulate matter,for which the reason have not been clearly elucidated.Here we measured carbonyl compounds and other trace gasses together with PM_(2.5)over urban Jinan in North China Plain during the winter.Markedly higher carbonyl concentrations(average:14.63±4.21 ppbv)were found during wintertime haze pollution,about one to three-times relative to those on nonhaze days,with slight difference in chemical composition except formaldehyde(HCHO).HCHO(3.68 ppbv),acetone(3.17 ppbv),and acetaldehyde(CH_3CHO)(2.83 ppbv)were the three most abundant species,accounting for~75% of the total carbonylson both haze and non-haze days.Results from observational-based model(OBM)with atmospheric oxidation capacity(AOC)indicated that AOC significantly increased with the increasing carbonyls during the winter haze events.Carbonyl photolysis have supplied key oxidants such as RO_(2) and HO_(2),and thereby enhancing the formation of fine particles and secondary organic aerosols,elucidating the observed haze-carbonyls inter-correlation.Diurnal variation with carbonyls exhibiting peak values at early-noon and night highlighted the combined contribution of both secondary formation and primary diesel-fuel sources.1-butene was further confirmed to be the major precursor for HCHO.This study confirms the great contribution of carbonyls to AOC,and also suggests that reducing the emissions of carbonyls would be an effective way to mitigate haze pollution in urban area of the NCP region.展开更多
A strongly declining aerosol radiative effect has been observed in China since 2013 after implementing the clean air action,yet its impact on wheat(Triticum aestivum L.)production remains unclear.We use satellite meas...A strongly declining aerosol radiative effect has been observed in China since 2013 after implementing the clean air action,yet its impact on wheat(Triticum aestivum L.)production remains unclear.We use satellite measures and a biophysical crop model to assess the impact of aerosol-induced radiative perturbations on winter wheat production in the agricultural belt of Henan province from 2013 to 2018.After calibrating parameters with the extended Fourier Amplitude Sensitivity Test(EFAST)and the generalized likelihood uncertainty estimation(GLUE)method,the DSSAT CERES-Wheat model was able to simulate crop biomass and yield more accurately.We found that the aerosol negatively impacted wheat biomass by 21.87%and yield by 22.48%from 2006 to 2018,and the biomass effects from planting to anthesis were more significant compared to anthesis to maturity.Due to the strict clean air action,under all-sky conditions,the surface solar shortwave radiation(SSR)in 2018 increased by about 7.08%over 2006-2013 during the wheat growing seasons.As a result of the improvement of crop photosynthesis,winter wheat biomass and yield increased by an average of 5.46%and 2.9%,respectively.Our findings show that crop carbon uptake and yield will benefit from the clean air action in China,helping to ensure national food and health security.展开更多
The“2+26”cities,suffering the most severe winter haze pollution,have been the key region for air quality improvement in China.Increasing prominent nitrate pollution is one of the most challenging environmental issue...The“2+26”cities,suffering the most severe winter haze pollution,have been the key region for air quality improvement in China.Increasing prominent nitrate pollution is one of the most challenging environmental issues in this region,necessitating development of an effective control strategy.Herein,we use observations,and state-of-the-art model simulations with scenario analysis and process analysis to quantify the effectiveness of the future SO_(2)-NO_(X)-VOC-NH_(3) emission control on nitrate pollution mitigation in“2+26”cities.Focusing on a serious winter haze episode,we find that limited NO_(X)emission reduction alone in the short-term period is a less effective choice than VOC or NH_3emission reduction alone to decrease nitrate concentrations,due to the accelerated NO_(X)-HNO_(3)conversion by atmospheric oxidants and the enhanced HNO_(3)to NO_(3)^(-)partition by ammonia,although deep NO_(X)emission reduction is essential in the long-term period.The synergistic NH_(3) and VOC emission control is strongly recommended,which can counteract the adverse effects of nonlinear photochemistry and aerosol chemical feedback to decrease nitrate more.Such extra benefits will be reduced if the synergistic NH_(3) and VOC reduction is delayed,and thus reducing emission of multiple precursors is urgently required for the effective control of increasingly severe winter nitrate pollution in“2+26”cities.展开更多
Haze is a pollution weather phenomenon that has been widely concerned by people in recent years. It has a significant impact on people’s production, life, and health. This study focuses on large-scale haze weather th...Haze is a pollution weather phenomenon that has been widely concerned by people in recent years. It has a significant impact on people’s production, life, and health. This study focuses on large-scale haze weather that happened in eastern China in late January 2021. The research uses multi-party data and synoptic analysis methods to analyze the occurrence, evolution, and end of the haze weather. The polar vortex, the change of the atmospheric circulation, the change of the cold air force, the temperature and humidity, and the rain and snow weather are the important reasons for this weathering process. It can be used for reference in future research on haze weather.展开更多
基金supported by the CAS Strategic Priority Research Program(Grant Nos.XDB05030200 and XDB05030101)the National Natural Science Foundation of China(Grant No.41278138)
文摘The Nested Air Quality Prediction Model System(NAQPMS)was used to investigate the temporal and spatial variations of PM2.5over tropospheric central eastern China in January 2013.The impact of regional transport and its implications on pollution prevention and control were also examined.Comparison between simulated and observed PM2.5showed NAQPMS was able to reproduce the evolution of PM2.5during heavy haze episodes.The results indicated that regional transport of PM2.5played an important role in regional haze episodes in the city cluster including Hebei,Beijing and Tianjin(HBT).The cross-city clusters transport outside HBT and transport among cities inside HBT contributed 20%–35%and 26%–35%of PM2.5as compared with local emission,in HBT respectively.To meet the Air Quality Standards for Grade II,90%,90%and65%of emissions would have to be cut down in Hebei,Tianjin and Beijing,if non-control strategy was taken in the surrounding city clusters of HBT.This implicated that control of emissions in one city cluster is not sufficient to reduce regional haze events,and joint efforts among city clusters are essential.Besides regional transports,two-way feedback between boundary-layer evolution and PM2.5also significantly contributed to the formation of heavy hazes,which contributed 30%of monthly average PM2.5concentration in HBT.
文摘Background:Corneal scarring following bacterial keratitis,particularly from Pseudomonas infections,poses significant challenges in ophthalmic care.Current treatments often fall short in effectively reducing corneal haze and restoring vision.To our knowledge,this is the first report documenting the use of topical losartan,an angiotensin II receptor antagonist known to inhibit the transforming growth factor-β(TGF-β)pathway,for treating corneal haze resulting from bacterial keratitis.Case Description:A 30-year-old male presented with a persistent corneal scar in his right eye,178 days post-Pseudomonas keratitis.Despite a prolonged course of topical corticosteroids,his best-corrected visual acuity(BCVA)stabilized at 20/40 with a hybrid contact lens over a 2-month period.Given the lack of improvement,we initiated treatment with topical losartan at a concentration of 0.8 mg/mL,administered six times daily.After 4 months of therapy,the patient’s BCVA improved to 20/25.Slit-lamp examination and corneal tomography revealed a significant reduction in corneal haze,indicating a positive response to the treatment.Conclusions:This case suggests that topical losartan may be a promising therapeutic option for reducing corneal opacity following bacterial keratitis by inhibiting the TGF-βpathway.However,further clinical studies are necessary to confirm its efficacy and safety in broader patient populations.
基金supported by the Princess Nourah bint Abdulrahman University Researchers Supporting Project number(PNURSP2025R848)Princess Nourah bint Abdulrahman University,Riyadh,Saudi Arabiathe Deanship of Scientific Research at Northern Border University,Arar,Saudi Arabia for funding this research work through the project number“NBU-FFR-2025-2932-09”.
文摘License plate recognition in haze-affected images is challenging due to feature distortions such as blurring and elongation,which lead to pixel displacements.This article introduces a Displacement Region Recognition Method(DR2M)to address such a problem.This method operates on displaced features compared to the training input observed throughout definite time frames.The technique focuses on detecting features that remain relatively stable under haze,using a frame-based analysis to isolate edges minimally affected by visual noise.The edge detection failures are identified using a bilateral neural network through displaced feature training.The training converges bilaterally towards the minimum edges from the maximum region.Thus,the training input and detected edges are used to identify the displacement between observed image frames to extract and differentiate the license plate region from the other vehicle regions.The proposed method maps the similarity feature between the detected and identified vehicle regions.This aids in leveraging the plate recognition precision with a high F1 score.Thus,this technique achieves a 10.27%improvement in identification precision,a 10.57%increase in F1 score,and a 9.73%reduction in false positive rate compared to baseline methods under maximum displacement conditions caused by haze.The technique attains an identification precision of 95.68%,an F1 score of 94.68%,and a false positive rate of 4.32%,indicating robust performance under haze-affected settings.
基金supported by the Natural Science Foundation of Jilin Province(No.YDZJ202401369ZYTS)the National Natural Science Foundation of China(No.42175140).
文摘The chemical composition of dew is closely related to the air quality.Since 2013,China has promulgated a series of laws and regulations focused on air pollution control,and remarkable results have been achieved over the past decade.As an indicator of near-surface air quality,the chemical composition of dew obviously changes.The dew quality was affected mainly by the local air quality.The mean dew pH was 6.3±0.4(n=186)from 2013 to 2023,and the order of ions was SO_(4)^(2-)(3180.7±3592.0μeq/L)>NH_(4)^(+)(2552.3±2971.8μeq/L)>Ca^(2+)(1006.2±945.5μeq/L)>NO_(3)^(-)(397.2±511.0μeq/L)>Cl^(-)(152.3±133.4μeq/L)>K^(+)(149.4±191.6μeq/L)>F^(-)(133.0±110.3μeq/L)>Na^(+)(123.8±94.9μeq/L)>Mg^(2+)(83.3±65.6μeq/L).The dew quality deteriorated on hazy days.There were no haze events during the condensation period after 2020,which caused a significant reduction in the concentration of the main ions in the dew.Over the past decade,electrical conductivity(EC),total dissolved solids(TDS),PM_(2.5) and PM_(10),as well as major ions(SO_(4)^(2-),NO_(3)^(-),NH_(4)^(+),Ca^(2+),Cl^(-),Na^(+),F^(-),K^(+)and Mg^(2+))in dew,have all tended to decrease.The annualmean NO_(3)^(-)concentration in 2023 was 86.5%lower than that in 2013,with values of 79.3%for SO_(4)^(2-),77.3%for Ca^(2+),76.7%for NH_(4)^(+),74.6%for K^(+),65.4%for Mg^(2+),63.4%for Na^(+),61.7%for Cl^(-),and 60.3%for F^(-).
基金supported by the National Key R&D Program of China(No.2022YFF0802501)the Key Research and Development Program of Shaanxi Province(No.2018-ZDXM3-01)the Youth Innovation Promotion Association of the Chinese Academy of Sciences(No.2019402)。
文摘In this study,online water-soluble inorganic ions were detected to deduce the formation mechanism of secondary inorganic aerosol in Xianyang,China during wintertime.The dominant inorganic ions of sulfate(SO_(4)^(2-)),nitrate(NO_(3)^(-)),and ammonium(NH_(4)^(+))(the sum of those is abbreviated as SNA)accounted for 17%,21%,and 12% of PM_(2.5)mass,respectively.While the air quality deteriorated from excellent to poor grades,the precursor gas sulfur dioxide(SO_(2))of SO_(4)^(2-)increased and then decreased with a fluctuation,while nitrogen dioxide(NO_(2))and ammonia(NH_(3)),precursors of NO_(3)^(-)and NH_(4)^(+),and SNA show increasing trends.Meteorological factors including boundary layer height(BLH),temperature,and wind speed also show decline trends,except relative humidity(RH).Meanwhile,the secondary conversion ratio shows a remarkable increasing trend,indicating that there was a strong secondary transformation.From the perspective of chemical mechanisms,RH is positively correlated with sulfur oxidation ratios(SOR),nitrogen oxidation ratios(NOR),and ammonia conversion ratios,representing that the increase of humidity could promote the generation of SNA.Notably,SOR and NOR were also positively related to the ammonia.On the one hand,the low wind speed and BLH led to the accumulation of pollutants.On the other hand,the increases of RH and ammonia promoted more formations of SNA and PM_(2.5).The results advance our identification of the contributors to the haze episodes and assist to establish more efficient emission controls in Xianyang,in addition to other cities with similar emission and geographical characteristics.
基金This work was supported by the National Natural Science Foundation of China(No.52078269).
文摘Sandstorm,which injects generous newly emerging microbes into the atmosphere covering cities,adversely affects the air quality in built environments.However,few studies have examined the change of airborne bacteria during severe sandstorm events.In this work,we analyzed the airborne bacteria during one of the strongest sandstorms in East Asia onMarch 15th,2021,which affected large areas of China and Mongolia.The characteristics of the sandstorm were compared with those of the subsequent clean and haze days.The composition of the bacterial community of air samples was investigated using quantitative polymerase chain reaction(qPCR)and high-throughput sequencing technology.During the sandstorm,the particulate matter(PM)concentration and bacterial richnesswere extremely high(PM_(2.5):207μg/m^(3);PM_(10):1630μg/m^(3);5700 amplicon sequence variants/m^(3)).In addition,the sandstorm brought 10 pathogenic bacterial genera to the atmosphere,posing a grave hazard to human health.As the sandstorm subsided,small bioaerosols(0.65–1.1μm)with a similar bacterial community remained suspended in the atmosphere,bringing possible long-lasting health risks.
基金supported by the National Natural Science Foundation of China(Nos.42005092,42275127,42075112and 41775127)the Natural Science Foundation of Shandong Province(No.ZR2020QD058)。
文摘Atmospheric carbonyl compounds play significant roles in the cycling of radicals and have exhibited surprisingly high levels in winter that were well correlated to particulate matter,for which the reason have not been clearly elucidated.Here we measured carbonyl compounds and other trace gasses together with PM_(2.5)over urban Jinan in North China Plain during the winter.Markedly higher carbonyl concentrations(average:14.63±4.21 ppbv)were found during wintertime haze pollution,about one to three-times relative to those on nonhaze days,with slight difference in chemical composition except formaldehyde(HCHO).HCHO(3.68 ppbv),acetone(3.17 ppbv),and acetaldehyde(CH_3CHO)(2.83 ppbv)were the three most abundant species,accounting for~75% of the total carbonylson both haze and non-haze days.Results from observational-based model(OBM)with atmospheric oxidation capacity(AOC)indicated that AOC significantly increased with the increasing carbonyls during the winter haze events.Carbonyl photolysis have supplied key oxidants such as RO_(2) and HO_(2),and thereby enhancing the formation of fine particles and secondary organic aerosols,elucidating the observed haze-carbonyls inter-correlation.Diurnal variation with carbonyls exhibiting peak values at early-noon and night highlighted the combined contribution of both secondary formation and primary diesel-fuel sources.1-butene was further confirmed to be the major precursor for HCHO.This study confirms the great contribution of carbonyls to AOC,and also suggests that reducing the emissions of carbonyls would be an effective way to mitigate haze pollution in urban area of the NCP region.
基金supported by the Joint Funds of the National Natural Science Foundation of China(No.U21A2014)the Science and Technology Development Program of Henan Province(No.232102321032)the support from the Henan Dabieshan National Field Observation and Research Station of Forest Ecosystem。
文摘A strongly declining aerosol radiative effect has been observed in China since 2013 after implementing the clean air action,yet its impact on wheat(Triticum aestivum L.)production remains unclear.We use satellite measures and a biophysical crop model to assess the impact of aerosol-induced radiative perturbations on winter wheat production in the agricultural belt of Henan province from 2013 to 2018.After calibrating parameters with the extended Fourier Amplitude Sensitivity Test(EFAST)and the generalized likelihood uncertainty estimation(GLUE)method,the DSSAT CERES-Wheat model was able to simulate crop biomass and yield more accurately.We found that the aerosol negatively impacted wheat biomass by 21.87%and yield by 22.48%from 2006 to 2018,and the biomass effects from planting to anthesis were more significant compared to anthesis to maturity.Due to the strict clean air action,under all-sky conditions,the surface solar shortwave radiation(SSR)in 2018 increased by about 7.08%over 2006-2013 during the wheat growing seasons.As a result of the improvement of crop photosynthesis,winter wheat biomass and yield increased by an average of 5.46%and 2.9%,respectively.Our findings show that crop carbon uptake and yield will benefit from the clean air action in China,helping to ensure national food and health security.
基金National Natural Science Foundation of China (No.22206106)the Scientific Research Start-up Funds from Tsinghua Shenzhen International Graduate School (No.QD2021015C)the Natural Science Foundation of Guangdong Province (No.2022A1515010705)。
文摘The“2+26”cities,suffering the most severe winter haze pollution,have been the key region for air quality improvement in China.Increasing prominent nitrate pollution is one of the most challenging environmental issues in this region,necessitating development of an effective control strategy.Herein,we use observations,and state-of-the-art model simulations with scenario analysis and process analysis to quantify the effectiveness of the future SO_(2)-NO_(X)-VOC-NH_(3) emission control on nitrate pollution mitigation in“2+26”cities.Focusing on a serious winter haze episode,we find that limited NO_(X)emission reduction alone in the short-term period is a less effective choice than VOC or NH_3emission reduction alone to decrease nitrate concentrations,due to the accelerated NO_(X)-HNO_(3)conversion by atmospheric oxidants and the enhanced HNO_(3)to NO_(3)^(-)partition by ammonia,although deep NO_(X)emission reduction is essential in the long-term period.The synergistic NH_(3) and VOC emission control is strongly recommended,which can counteract the adverse effects of nonlinear photochemistry and aerosol chemical feedback to decrease nitrate more.Such extra benefits will be reduced if the synergistic NH_(3) and VOC reduction is delayed,and thus reducing emission of multiple precursors is urgently required for the effective control of increasingly severe winter nitrate pollution in“2+26”cities.
文摘Haze is a pollution weather phenomenon that has been widely concerned by people in recent years. It has a significant impact on people’s production, life, and health. This study focuses on large-scale haze weather that happened in eastern China in late January 2021. The research uses multi-party data and synoptic analysis methods to analyze the occurrence, evolution, and end of the haze weather. The polar vortex, the change of the atmospheric circulation, the change of the cold air force, the temperature and humidity, and the rain and snow weather are the important reasons for this weathering process. It can be used for reference in future research on haze weather.
