Atmospheric particle pollution is one of the major factors leading to degradation of ancient wall paintings,particularly heritage sites in arid and semi-arid regions.However,current systematic research on the changes,...Atmospheric particle pollution is one of the major factors leading to degradation of ancient wall paintings,particularly heritage sites in arid and semi-arid regions.However,current systematic research on the changes,sources,and influential factors of atmospheric particulate matter and its water-soluble ion concentrations is not sufficient.Thus,the major water-soluble ion concentrations,sources,and influential factors of atmospheric particles PM_(2.5) and PM_(10)(particulate matter with an aerodynamic equivalent diameter≤2.5 and 10.0μm,respectively,in ambient air)were collected from Cave 16 and its ambient exterior environment in the Dunhuang Mogao Grottoes,China,between April 2015 and March 2016.Results showed that the concentrations of PM_(2.5) and PM_(10) inside and outside the cave were the highest in March 2016 and the lowest in December 2015.The higher particle concentration from March to May was related to the frequent occurrence of sand and dust events,and the lower particle concentration from June to September was associated with good diffusion conditions,increased precipitation,and an established cave shelterbelt.The concentration of particulate matter inside the cave was affected by the concentration of particles in the air outside the cave.Ca2+,NH+4,Na+,Cl-,and SO2-4were the main components of the total ions of PM_(2.5) and PM_(10) both inside and outside the cave.The total ions inside the cave were frequently affected by the disturbance of tourists'activities during the peak tourist season from May to August.Under the influence of dust,the total concentrations of Cl-,SO2-4,Na+,NH+4,and Ca2+in particles of different sizes inside and outside the cave increased,and the concentrations of Cl-,SO2-4,Na+,and Ca2+decreased during precipitation period.Backward air mass trajectory analysis suggested that the pollutants were mainly from Xinjiang,China.The pollutant sources of air particulates are straw burning,secondary pollution sources,soil dust,dry spring rivers,and tourist activities.展开更多
A method of quantification of perfluorinated compounds(PFCs)from atmospheric particulate matter(APM)is described.A single step pretreatment method,selective pressurized liquid extraction(SPLE),was developed to reduce ...A method of quantification of perfluorinated compounds(PFCs)from atmospheric particulate matter(APM)is described.A single step pretreatment method,selective pressurized liquid extraction(SPLE),was developed to reduce the high matrix background and avoid contamination from commonly used multiple sample pretreatment steps.An effective sorbent was selected to purify the PFCs during SPLE,followed by liquid chromatography-tandem mass spectrometry(LC–MS/MS),for quantification of PFCs.Conditions affecting the SPLE efficiency,including temperature,static extraction time,and number of extraction cycles used,were studied.The optimum conditions were found to be 120℃,10 min,and 3 cycles,respectively.LC-MS/MS method was developed to obtain the optimal sensitivity specific to PFCs.The method detection limits(MDLs)were 0.006 to 0.48 ng/g for the PFCs studied and the linear response range was from 0.1 to 100 ng/g.To ensure accurate values were obtained,each step of the experiment was evaluated and controlled to prevent contamination.The optimized method was tested by performing spiking experiments in natural particulate matter matrices and good rates of recovery and reproducibility were obtained for all target compounds.Finally,the method was successfully used to measure 16 PFCs in the APM samples collected in Beijing over five years from 2015 to 2019.It is observed that some PFCs follow the trend of total PFC changes,and can be attributed to the environment influencing events and policy enforcement,while others don't seem to change as much with time of the year or from year to year.展开更多
Inhalable particles(PM_(10)),with aerodynamic equivalent diameters that are generally 10 micrometers or smaller,are basic pollutants in many areas,especially in northern China,and thus the pollution from PM_(10)inhala...Inhalable particles(PM_(10)),with aerodynamic equivalent diameters that are generally 10 micrometers or smaller,are basic pollutants in many areas,especially in northern China,and thus the pollution from PM_(10)inhalable particulate matter is a growing concern for public health.Independent long-term observations are necessary to evaluate the efficacy of PM_(10)reduction actions.Variations in the PM_(10)concentration from 2006 to 2017 at an observation station(NJ)in Beijing were recorded and analyzed.The average value±1 standard deviation of daily mean PM_(10)concentrations was 138.8±96.1μg m^(-3)for 1307 days(accounting for 34.7%of the total days),showing PM_(10)concentration exceeding the National Ambient Air Quality Standard(NAAQS)24-h average of 150μg m^(-3).Particulate concentration depended upon various meteorological conditions as also observed in this work:at low wind speed(<4 m s^(-1)),the concentrations of PM_(10) revealed a downward trend with-19μg m^(-3)per unit of wind speed,but when wind speed rose(>4 m s^(-1)),the values increased by 49μg m^(-3)per unit of wind speed.In Beijing,air masses from northwest China,especially from the Gobi Desert and other desert areas,had net contributions to long-range transport of natural dust,enhancing the PM_(10)concentrations by up to 29%.Overall,PM_(10)mass concentration showed a significant downward trend with-8.0μg/m3/yr from 2006 to 2017.Although with higher fluctuations in recorded data,similar downward trends derived from the government released data were also found at the nearby districts.The result delivered a proof of efficacy for the reduction actions recently adopted to limit PM_(10)concentrations in Beijing.Very significant difference of diurnal changes in PM_(10) concentrations was also found in two periods of 2006-2011 and 2012-2017,which might be due to the different contributions of fugitive dust.Nevertheless,further efforts,especially on controlling fugitive dust,should be planned as the PM_(10) concentration annual mean value(94μg m^(-3))in 2017 still exceeded the NAAQS standard.The results showed that there is still a long way to go to reduce PM_(10)in Beijing.展开更多
The meteorological big data in Beijing area are typical multi-dimensional big data containing spatiotemporal characteristics,which have important research value for researches related to urban human settlement environ...The meteorological big data in Beijing area are typical multi-dimensional big data containing spatiotemporal characteristics,which have important research value for researches related to urban human settlement environment.With the help of computer programming and software processing,big data crawling,integration,extraction and multi-dimensional information fusion can be realized quickly and effectively,so as to obtain the data set needed for research and realize the target of visualization.Through big data analysis of wind environment,thermal environment and total atmospheric suspended particulate pollutants in Beijing area,it was found that the average wind speed in Beijing area decreased signifi cantly in recent 40 years,while the surface temperature increased signifi cantly;urban heat island effect was signifi cant,and the phenomenon of atmospheric suspended particulate pollution was relatively common.The spatial distribution of the three climatic and environmental data was not balanced and had signifi cant regularity and correlation.Improving urban ventilation corridors and improving urban ventilation capacity is a feasible way to improve urban heat island effect and reduce urban climate issues such as atmospheric particulate pollution.展开更多
基金supported by the National Natural Science Foundation of China(51962001,32260292)the National Key Research&Development Projects(2020YFC1522200)the Gansu Provincial Science and Technology Plan Project(20JR5RA051,21YF1FF371).
文摘Atmospheric particle pollution is one of the major factors leading to degradation of ancient wall paintings,particularly heritage sites in arid and semi-arid regions.However,current systematic research on the changes,sources,and influential factors of atmospheric particulate matter and its water-soluble ion concentrations is not sufficient.Thus,the major water-soluble ion concentrations,sources,and influential factors of atmospheric particles PM_(2.5) and PM_(10)(particulate matter with an aerodynamic equivalent diameter≤2.5 and 10.0μm,respectively,in ambient air)were collected from Cave 16 and its ambient exterior environment in the Dunhuang Mogao Grottoes,China,between April 2015 and March 2016.Results showed that the concentrations of PM_(2.5) and PM_(10) inside and outside the cave were the highest in March 2016 and the lowest in December 2015.The higher particle concentration from March to May was related to the frequent occurrence of sand and dust events,and the lower particle concentration from June to September was associated with good diffusion conditions,increased precipitation,and an established cave shelterbelt.The concentration of particulate matter inside the cave was affected by the concentration of particles in the air outside the cave.Ca2+,NH+4,Na+,Cl-,and SO2-4were the main components of the total ions of PM_(2.5) and PM_(10) both inside and outside the cave.The total ions inside the cave were frequently affected by the disturbance of tourists'activities during the peak tourist season from May to August.Under the influence of dust,the total concentrations of Cl-,SO2-4,Na+,NH+4,and Ca2+in particles of different sizes inside and outside the cave increased,and the concentrations of Cl-,SO2-4,Na+,and Ca2+decreased during precipitation period.Backward air mass trajectory analysis suggested that the pollutants were mainly from Xinjiang,China.The pollutant sources of air particulates are straw burning,secondary pollution sources,soil dust,dry spring rivers,and tourist activities.
基金supported by the NQI Project of National key R&D Program of China (No.2016YFF0201102)the project for the“Development of analytical method and certified reference materials for tracing air pollutant source” (No.21AKY1514)from the National Institute of Metrology,Beijing,China。
文摘A method of quantification of perfluorinated compounds(PFCs)from atmospheric particulate matter(APM)is described.A single step pretreatment method,selective pressurized liquid extraction(SPLE),was developed to reduce the high matrix background and avoid contamination from commonly used multiple sample pretreatment steps.An effective sorbent was selected to purify the PFCs during SPLE,followed by liquid chromatography-tandem mass spectrometry(LC–MS/MS),for quantification of PFCs.Conditions affecting the SPLE efficiency,including temperature,static extraction time,and number of extraction cycles used,were studied.The optimum conditions were found to be 120℃,10 min,and 3 cycles,respectively.LC-MS/MS method was developed to obtain the optimal sensitivity specific to PFCs.The method detection limits(MDLs)were 0.006 to 0.48 ng/g for the PFCs studied and the linear response range was from 0.1 to 100 ng/g.To ensure accurate values were obtained,each step of the experiment was evaluated and controlled to prevent contamination.The optimized method was tested by performing spiking experiments in natural particulate matter matrices and good rates of recovery and reproducibility were obtained for all target compounds.Finally,the method was successfully used to measure 16 PFCs in the APM samples collected in Beijing over five years from 2015 to 2019.It is observed that some PFCs follow the trend of total PFC changes,and can be attributed to the environment influencing events and policy enforcement,while others don't seem to change as much with time of the year or from year to year.
基金National Natural Science Foundation of China(91744206)Shangdianzi National Atmosphere Background Station Open Foundation(SDZ2020615)。
文摘Inhalable particles(PM_(10)),with aerodynamic equivalent diameters that are generally 10 micrometers or smaller,are basic pollutants in many areas,especially in northern China,and thus the pollution from PM_(10)inhalable particulate matter is a growing concern for public health.Independent long-term observations are necessary to evaluate the efficacy of PM_(10)reduction actions.Variations in the PM_(10)concentration from 2006 to 2017 at an observation station(NJ)in Beijing were recorded and analyzed.The average value±1 standard deviation of daily mean PM_(10)concentrations was 138.8±96.1μg m^(-3)for 1307 days(accounting for 34.7%of the total days),showing PM_(10)concentration exceeding the National Ambient Air Quality Standard(NAAQS)24-h average of 150μg m^(-3).Particulate concentration depended upon various meteorological conditions as also observed in this work:at low wind speed(<4 m s^(-1)),the concentrations of PM_(10) revealed a downward trend with-19μg m^(-3)per unit of wind speed,but when wind speed rose(>4 m s^(-1)),the values increased by 49μg m^(-3)per unit of wind speed.In Beijing,air masses from northwest China,especially from the Gobi Desert and other desert areas,had net contributions to long-range transport of natural dust,enhancing the PM_(10)concentrations by up to 29%.Overall,PM_(10)mass concentration showed a significant downward trend with-8.0μg/m3/yr from 2006 to 2017.Although with higher fluctuations in recorded data,similar downward trends derived from the government released data were also found at the nearby districts.The result delivered a proof of efficacy for the reduction actions recently adopted to limit PM_(10)concentrations in Beijing.Very significant difference of diurnal changes in PM_(10) concentrations was also found in two periods of 2006-2011 and 2012-2017,which might be due to the different contributions of fugitive dust.Nevertheless,further efforts,especially on controlling fugitive dust,should be planned as the PM_(10) concentration annual mean value(94μg m^(-3))in 2017 still exceeded the NAAQS standard.The results showed that there is still a long way to go to reduce PM_(10)in Beijing.
基金Sponsored by National Natural Science Foundation of China(51708004)YuYou Talent Training Program of North University of Technology(215051360020XN160/009)+1 种基金General Program of Beijing Natural Science Foundation(8202017)2018 Beijing Municipal University Academic Human Resources Development:Youth Talent Support Program(PXM2018-014212-000043).
文摘The meteorological big data in Beijing area are typical multi-dimensional big data containing spatiotemporal characteristics,which have important research value for researches related to urban human settlement environment.With the help of computer programming and software processing,big data crawling,integration,extraction and multi-dimensional information fusion can be realized quickly and effectively,so as to obtain the data set needed for research and realize the target of visualization.Through big data analysis of wind environment,thermal environment and total atmospheric suspended particulate pollutants in Beijing area,it was found that the average wind speed in Beijing area decreased signifi cantly in recent 40 years,while the surface temperature increased signifi cantly;urban heat island effect was signifi cant,and the phenomenon of atmospheric suspended particulate pollution was relatively common.The spatial distribution of the three climatic and environmental data was not balanced and had signifi cant regularity and correlation.Improving urban ventilation corridors and improving urban ventilation capacity is a feasible way to improve urban heat island effect and reduce urban climate issues such as atmospheric particulate pollution.
