Chemical modifications of proteins induced by ambient ozone(O_(3))and nitrogen oxides(NOx)are of public health concerns due to their potential to trigger respiratory diseases.The laboratory and environmental exposure ...Chemical modifications of proteins induced by ambient ozone(O_(3))and nitrogen oxides(NOx)are of public health concerns due to their potential to trigger respiratory diseases.The laboratory and environmental exposure systems have been widely used to investigate their relevant mechanism in the atmosphere.Using bovine serum albumin(BSA)as a model protein,we evaluated the two systems and aimed to reduce the uncertainties of both the reactants and products in the corresponding kinetic study.In the laboratory simulation system,the generated gaseous pollutants showed negligible losses.Ten layers of BSA were coated on the flow tube with protein extraction recovery of 87.4%.For environmental exposure experiment,quartz fiber filter was selected as the upper filter with low gaseous O_(3)(8.0%)and NO_(2)(1.7%)losses,and cellulose acetate filter was appropriate for the lower filter with protein extraction efficiency of 95.2%.The protein degradation process was observed without the exposure to atmospheric oxidants and contributed to the loss of protein monomer mass fractions,while environmental factors(e.g.,molecular oxygen and ultraviolet)may cause greater protein monomer losses.Based on the evaluation,the study exemplarily applied the two systems to protein modification and both showed that O_(3) promotes the protein oligomerization and nitration,while increased temperature can accelerate the oligomerization and increased relative humidity can inhibit the nitration in the environmental exposure samples.The developed laboratory and environmental systems are suitable for studying protein modifications formed under different atmospheric conditions.A combination of the two will further reveal the actual mechanism of protein modifications.展开更多
Water toxicity determination with electrochemically active bacteria(EAB)shows promise for providing early warnings for heavy metal pollution in water.However,thus far,only idealized tests with a few types of heavy met...Water toxicity determination with electrochemically active bacteria(EAB)shows promise for providing early warnings for heavy metal pollution in water.However,thus far,only idealized tests with a few types of heavy metals have been conducted.In this study,an automatic water-toxicitydetermination system with high technical maturity was established,and the toxicological properties of common heavy metals were systematically assessed.The results demonstrated that the common heavy metals linearly inhibited EAB currents in the range of 0.1 mg/L to 0.5 mg/L.The toxicity ranking of the tested heavy metals was Pb^(2+)>Tl^(3+)>Cu^(2+)>Cd^(2+)>Zn^(2+)>Ni^(2+)>Hg^(2+)>As^(3+).The toxicity interaction mainly exhibited an antagonistic effect in binary heavy metal mixtures.The system can accurately determine surface water toxicity and rapidly monitor heavy metal pollution,with good repeatability and a long lifetime.Overall,this study demonstrates that EAB are capable of long-term(>60 d)surface water quality monitoring and on-site early warning of heavy metal pollution.展开更多
Amines are important nitrogen-containing compounds in fine particles(PM2.5)in the atmosphere.Observations are necessary for in-depth understanding on the characteristics,sources and atmospheric processes of aminiums.I...Amines are important nitrogen-containing compounds in fine particles(PM2.5)in the atmosphere.Observations are necessary for in-depth understanding on the characteristics,sources and atmospheric processes of aminiums.In this study,the observation of ten C_(1)–C_(4) aminiums in PM_(2.5) was conducted in January and March of 2021 in suburban Guangzhou.The concentration and composition of aminiums showed significant differences between the pollution episodes and non-episode periods.Seasonal difference was also observed between winter and spring.The influence of meteorological factors(i.e.,wind speed,atmospheric pressure,temperature and relative humidity)was investigated.The variations of aminiums were also affected by different sources.Anthropogenic sources were suggested to be major contributor to aminiums in the pollution episodes,while biological sources were important sources to aminiums in the non-episode periods,especially in spring.Positive matrix factorization receptor model was applied to investigate the source contributions,and four major sources were identified.The results show that vehicular emission,industrial production,biological emission and soil/dust were the major sources of aminiums.This study emphasizes the importance of source contribution and meteorological conditions on the variations of aminiums,which provides further understanding of organic nitrogen in the atmosphere.展开更多
The majority(up to 90%)of riverine materials is transported from the continent to the ocean mainly in flood events.It is thus crucial to characterize the geochemistry of elements and their flux in river system in orde...The majority(up to 90%)of riverine materials is transported from the continent to the ocean mainly in flood events.It is thus crucial to characterize the geochemistry of elements and their flux in river system in order to better constrain their global biogeochemical cycling and impact on the oceanic ecosystem.However,the geochemical behavior including the distribution,migration and partitioning of typical metal elements amongst diff erent phases,during hydrodynamic flood event remains still to be well explored.Here,we investigated the geochemical behaviors of typical metal elements in dissolved phase and suspended particulate matter collected from a single flood event in the natural Chishui River,Southwest China.The results showed clearly that the geochemistry of metal elements was largely controlled by the hydrodynamic eff ect,of which the diff erent flowrates introduce a natural sorting of diff erent mineral particles transported at diff erent flood stages,depending on their shape,size and density.The maximum concentrations of alkaline and alkaline earth metals(Li,Mg,K,Rb and Sr)in SPM appeared before the flood peak,which was largely controlled by aluminosilicate minerals.However,transition metals(Cr,Mn,Fe,Ni and Cu)showed their abundance peaks lagging behind the flowrate summit,as a result of the late arrival of coarse particles or heavy minerals,evidenced by the mineralogical phase analysis.In addition,the distribution coe fficient(K_(d))between particulate and dissolved loads were lower and stable for soluble alkali/alkaline earth metals which could be aff ected by pH,while higher and fluctuant for transition metals that were largely influenced by SPM content.Overall,the present study reveals clear eff ects of hydrodynamic sorting on the geochemistry of metal elements during the flood event of the natural Chishui River,which should be taken into account when characterizing the riverine flux and their impact on marine ecosystem.展开更多
This study investigates seasonal variations of mass absorption efficiency of elemental carbon(MAE_(EC))and possible influencing factors in urban Guangzhou of South China.Mass concentrations of elemental carbon(EC)and ...This study investigates seasonal variations of mass absorption efficiency of elemental carbon(MAE_(EC))and possible influencing factors in urban Guangzhou of South China.Mass concentrations of elemental carbon(EC)and organic carbon(OC)in PM_(2.5) and aerosol absorption coefficient(b_(ap))at multi-wavelengths were simultaneously measured in four seasons of 2018-2019 at hourly resolution by a semi-continuous carbon analyzer and an aethalometer.Seasonal average mass concentrations of EC were in the range of 1.36-1.70μgC/m^(3) with a lower value in summer than in the other seasons,while those of OC were in the range of 4.70–6.49μgC/m^(3) with the lowest value in summer and the highest in autumn.Vehicle exhaust from local traffic was identified to be the predominant source of carbonaceous aerosols.The average aerosol absorption Angstrom exponents(AAE)were lower than 1.2 in four seasons,indicating EC and b_(ap) were closely related with vehicle exhaust.Seasonal MAE EC at 550 nm was 11.0,8.5,10.4 and 11.3 m^(2)/g in spring,summer,autumn,and winter,respectively.High MAE EC was related with the high mass ratio of non-carbonaceous aerosols to EC and high ambient relative humidity.展开更多
基金supported by the National Natural Science Foundation of China(Nos.41975156,41675119)。
文摘Chemical modifications of proteins induced by ambient ozone(O_(3))and nitrogen oxides(NOx)are of public health concerns due to their potential to trigger respiratory diseases.The laboratory and environmental exposure systems have been widely used to investigate their relevant mechanism in the atmosphere.Using bovine serum albumin(BSA)as a model protein,we evaluated the two systems and aimed to reduce the uncertainties of both the reactants and products in the corresponding kinetic study.In the laboratory simulation system,the generated gaseous pollutants showed negligible losses.Ten layers of BSA were coated on the flow tube with protein extraction recovery of 87.4%.For environmental exposure experiment,quartz fiber filter was selected as the upper filter with low gaseous O_(3)(8.0%)and NO_(2)(1.7%)losses,and cellulose acetate filter was appropriate for the lower filter with protein extraction efficiency of 95.2%.The protein degradation process was observed without the exposure to atmospheric oxidants and contributed to the loss of protein monomer mass fractions,while environmental factors(e.g.,molecular oxygen and ultraviolet)may cause greater protein monomer losses.Based on the evaluation,the study exemplarily applied the two systems to protein modification and both showed that O_(3) promotes the protein oligomerization and nitration,while increased temperature can accelerate the oligomerization and increased relative humidity can inhibit the nitration in the environmental exposure samples.The developed laboratory and environmental systems are suitable for studying protein modifications formed under different atmospheric conditions.A combination of the two will further reveal the actual mechanism of protein modifications.
基金financially supported by grants from the Key-Area Research and Development Program of Guangdong Province(No.2022B0303040001).
文摘Water toxicity determination with electrochemically active bacteria(EAB)shows promise for providing early warnings for heavy metal pollution in water.However,thus far,only idealized tests with a few types of heavy metals have been conducted.In this study,an automatic water-toxicitydetermination system with high technical maturity was established,and the toxicological properties of common heavy metals were systematically assessed.The results demonstrated that the common heavy metals linearly inhibited EAB currents in the range of 0.1 mg/L to 0.5 mg/L.The toxicity ranking of the tested heavy metals was Pb^(2+)>Tl^(3+)>Cu^(2+)>Cd^(2+)>Zn^(2+)>Ni^(2+)>Hg^(2+)>As^(3+).The toxicity interaction mainly exhibited an antagonistic effect in binary heavy metal mixtures.The system can accurately determine surface water toxicity and rapidly monitor heavy metal pollution,with good repeatability and a long lifetime.Overall,this study demonstrates that EAB are capable of long-term(>60 d)surface water quality monitoring and on-site early warning of heavy metal pollution.
基金The authors thank the financial support of the National Natural Science Foundation of China(grant numbers 41975156,41675119)Fundamental Research Funds for the Central Universities(grant number 2014Zz0054).
文摘Amines are important nitrogen-containing compounds in fine particles(PM2.5)in the atmosphere.Observations are necessary for in-depth understanding on the characteristics,sources and atmospheric processes of aminiums.In this study,the observation of ten C_(1)–C_(4) aminiums in PM_(2.5) was conducted in January and March of 2021 in suburban Guangzhou.The concentration and composition of aminiums showed significant differences between the pollution episodes and non-episode periods.Seasonal difference was also observed between winter and spring.The influence of meteorological factors(i.e.,wind speed,atmospheric pressure,temperature and relative humidity)was investigated.The variations of aminiums were also affected by different sources.Anthropogenic sources were suggested to be major contributor to aminiums in the pollution episodes,while biological sources were important sources to aminiums in the non-episode periods,especially in spring.Positive matrix factorization receptor model was applied to investigate the source contributions,and four major sources were identified.The results show that vehicular emission,industrial production,biological emission and soil/dust were the major sources of aminiums.This study emphasizes the importance of source contribution and meteorological conditions on the variations of aminiums,which provides further understanding of organic nitrogen in the atmosphere.
基金National Natural Science Foundation of China,42103008,Hongming Cai。
文摘The majority(up to 90%)of riverine materials is transported from the continent to the ocean mainly in flood events.It is thus crucial to characterize the geochemistry of elements and their flux in river system in order to better constrain their global biogeochemical cycling and impact on the oceanic ecosystem.However,the geochemical behavior including the distribution,migration and partitioning of typical metal elements amongst diff erent phases,during hydrodynamic flood event remains still to be well explored.Here,we investigated the geochemical behaviors of typical metal elements in dissolved phase and suspended particulate matter collected from a single flood event in the natural Chishui River,Southwest China.The results showed clearly that the geochemistry of metal elements was largely controlled by the hydrodynamic eff ect,of which the diff erent flowrates introduce a natural sorting of diff erent mineral particles transported at diff erent flood stages,depending on their shape,size and density.The maximum concentrations of alkaline and alkaline earth metals(Li,Mg,K,Rb and Sr)in SPM appeared before the flood peak,which was largely controlled by aluminosilicate minerals.However,transition metals(Cr,Mn,Fe,Ni and Cu)showed their abundance peaks lagging behind the flowrate summit,as a result of the late arrival of coarse particles or heavy minerals,evidenced by the mineralogical phase analysis.In addition,the distribution coe fficient(K_(d))between particulate and dissolved loads were lower and stable for soluble alkali/alkaline earth metals which could be aff ected by pH,while higher and fluctuant for transition metals that were largely influenced by SPM content.Overall,the present study reveals clear eff ects of hydrodynamic sorting on the geochemistry of metal elements during the flood event of the natural Chishui River,which should be taken into account when characterizing the riverine flux and their impact on marine ecosystem.
基金supported by the National Natural Science Foundation of China(Nos.41775155,41875160 and 41475119).
文摘This study investigates seasonal variations of mass absorption efficiency of elemental carbon(MAE_(EC))and possible influencing factors in urban Guangzhou of South China.Mass concentrations of elemental carbon(EC)and organic carbon(OC)in PM_(2.5) and aerosol absorption coefficient(b_(ap))at multi-wavelengths were simultaneously measured in four seasons of 2018-2019 at hourly resolution by a semi-continuous carbon analyzer and an aethalometer.Seasonal average mass concentrations of EC were in the range of 1.36-1.70μgC/m^(3) with a lower value in summer than in the other seasons,while those of OC were in the range of 4.70–6.49μgC/m^(3) with the lowest value in summer and the highest in autumn.Vehicle exhaust from local traffic was identified to be the predominant source of carbonaceous aerosols.The average aerosol absorption Angstrom exponents(AAE)were lower than 1.2 in four seasons,indicating EC and b_(ap) were closely related with vehicle exhaust.Seasonal MAE EC at 550 nm was 11.0,8.5,10.4 and 11.3 m^(2)/g in spring,summer,autumn,and winter,respectively.High MAE EC was related with the high mass ratio of non-carbonaceous aerosols to EC and high ambient relative humidity.
