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
Annual haze in Northern Thailand has become increasingly severe,impacting health and the environment.How-ever,the sources of the haze remain poorly quantified due to limited observational data on aerosol molecular tra...Annual haze in Northern Thailand has become increasingly severe,impacting health and the environment.How-ever,the sources of the haze remain poorly quantified due to limited observational data on aerosol molecular tracers.This study comprehensively investigates chemical composition of PM_(2.5),including both inorganic and organic compounds throughout haze and post-haze periods in 2019 at a rural site of Northern Thailand.Average PM_(2.5) concentrations during haze and post-haze period were 87±36 and 21±11μg/m^(3),respectively.Organic matter was the dominant contributor in PM_(2.5) mass,followed by water soluble inorganic ions and mineral dust.Molecular markers,including levoglucosan,dehydroabietic acid,and 4-nitrocatechol,and ions(Cl^(-),and K^(+)),were used to characterize low haze(PM_(2.5)<100μg/m^(3))and episodic haze(PM_(2.5)>100μg/m^(3)).Low haze is associated with local aerosols from agricultural waste burning,while episodic haze is linked to aged aerosols from mixed agricultural waste,softwood,and hardwood burning.Source apportionment incorporating these molecular markers in receptor modelling(Positive matrix factorization),identified three distinct biomass burning sources:mixed,local,and aged biomass burnings,contributing 31,19 and 13%of PM_(2.5) during haze period.During post-haze period,contributions shifted,with local biomass burning(32%)comparable to secondary sulfate(34%)and mixed dust and traffic sources(26%).These findings demonstrate that both regional and local sources con-tribute to severe haze,highlighting the need for integrated policies for cross-border cooperation as well as stricter regulations to reduce biomass burning in Northern Thailand and Southeast Asia.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
Based on meteorology and environment monitoring data in January,2008 in Liaoning central region,a typical haze weather process was analyzed.The results showed that haze was formed due to the stable weather condition i...Based on meteorology and environment monitoring data in January,2008 in Liaoning central region,a typical haze weather process was analyzed.The results showed that haze was formed due to the stable weather condition in the earth surface and upper air layer in Liaoning central region.Especially because that the weakening of atmospheric dispersion ability in the urban boundary layer that was 500 m under earth surface,caused the pollutant in the air can not disperse.Thus,it resulted in the deterioration of air quality,increase of concentration of particulate mass,and declination of visibility.And in the end,haze formed.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Annual haze in Northern Thailand has become increasingly severe,impacting health and the environment.How-ever,the sources of the haze remain poorly quantified due to limited observational data on aerosol molecular tracers.This study comprehensively investigates chemical composition of PM_(2.5),including both inorganic and organic compounds throughout haze and post-haze periods in 2019 at a rural site of Northern Thailand.Average PM_(2.5) concentrations during haze and post-haze period were 87±36 and 21±11μg/m^(3),respectively.Organic matter was the dominant contributor in PM_(2.5) mass,followed by water soluble inorganic ions and mineral dust.Molecular markers,including levoglucosan,dehydroabietic acid,and 4-nitrocatechol,and ions(Cl^(-),and K^(+)),were used to characterize low haze(PM_(2.5)<100μg/m^(3))and episodic haze(PM_(2.5)>100μg/m^(3)).Low haze is associated with local aerosols from agricultural waste burning,while episodic haze is linked to aged aerosols from mixed agricultural waste,softwood,and hardwood burning.Source apportionment incorporating these molecular markers in receptor modelling(Positive matrix factorization),identified three distinct biomass burning sources:mixed,local,and aged biomass burnings,contributing 31,19 and 13%of PM_(2.5) during haze period.During post-haze period,contributions shifted,with local biomass burning(32%)comparable to secondary sulfate(34%)and mixed dust and traffic sources(26%).These findings demonstrate that both regional and local sources con-tribute to severe haze,highlighting the need for integrated policies for cross-border cooperation as well as stricter regulations to reduce biomass burning in Northern Thailand and Southeast Asia.
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 Liaoning Meteorology Bureau Scientific Research Fund (200808)China Meterological Administration Shenyang Atmospheric Science Research Bureau Scieatific Resarch Fund ProgramScientific Research Special Fund for Public Welfare Industry in 2008 (GYHY20080620)
文摘Based on meteorology and environment monitoring data in January,2008 in Liaoning central region,a typical haze weather process was analyzed.The results showed that haze was formed due to the stable weather condition in the earth surface and upper air layer in Liaoning central region.Especially because that the weakening of atmospheric dispersion ability in the urban boundary layer that was 500 m under earth surface,caused the pollutant in the air can not disperse.Thus,it resulted in the deterioration of air quality,increase of concentration of particulate mass,and declination of visibility.And in the end,haze formed.
