In this study,the particle size-resolved distribution from a China-3 certificated light-duty diesel vehicle was measured by using a portable emission measurement system（PEMS）.In order to examine the influences of ve...In this study,the particle size-resolved distribution from a China-3 certificated light-duty diesel vehicle was measured by using a portable emission measurement system（PEMS）.In order to examine the influences of vehicle specific power（VSP） and high-altitude operation,measurements were conducted at 8 constant speeds,which ranged from 10 to 80 km/hr at10 km/hr intervals,and two different high altitudes,namely 2200 and 3200 m.The results demonstrated that the numbers of particles in all size ranges decreased significantly as VSP increased when the test vehicle was running at lower speeds（〈 20 km/hr）,while at a moderate speed（between 30 and 60 km/hr）,the particle number was statistically insensitive to increase VSP.Under high-speed cruising conditions,the numbers of ultrafine particles and PM2.5were insensitive to changes in VSP,but the numbers of nanoparticles and PM10 surged considerably.An increase in the operational altitude of the test vehicle resulted in increased particle number emissions at low and high driving speeds;however,particle numbers obtained at moderate speeds decreased as altitude rose.When the test vehicle was running at moderate speeds,particle numbers measured at the two altitudes were very close,except for comparatively higher number concentrations of nanoparticles measured at 2200 m.展开更多
This paper considers the distribution of technogenic 137Cs and naturally occurring radionuclides:238 U,232 Th and40 R concentrations in soils and 137Cs in atmospheric dry depositions by altitudinal belts of the Aragat...This paper considers the distribution of technogenic 137Cs and naturally occurring radionuclides:238 U,232 Th and40 R concentrations in soils and 137Cs in atmospheric dry depositions by altitudinal belts of the Aragats mountain massif,Republic of Armenia.Undisturbed soil samples were collected at altitudes from 1000 to 3200 m.For the determination of geochemical variability,two soil sampling campaigns were undertaken.Atmospheric dry depositions were sampled from five stations at1100-3200 m collected onto organic fiber filters between June and December 2016.137Cs activity was measured using a high-purity Germanium detector coupled to a multichannel analyzer(Canberra).Results indicated that specific activity of 137Cs in soils at 1000 m is495-528 Bq m^-2,andat3200 mis10,500-11,470 Bq m^-2.No correlation observed for 137Cs versus naturally occurring radionuclides,which varies in distribution by altitude.Specific activities of 137Cs in dry atmospheric depositions varies from 1.06 at 846 m to2.37 Bq m^-2 per quarter at 3200 m and increases as the altitude increases.Activities of 137Cs in soil and dry atmospheric deposition correlated significantly,and 137Cs activity in soils and atmospheric dry depositions decrease as the absolute altitude decreases.The 50-year effective dose from exposure to 137Cs fallout varies with altitude from 0.007 to 1.42 m Sv.展开更多
Studies on the elevation gradient distribution of polycyclic aromatic hydrocarbons(PAHs)have mainly focused on high-altitude regions like the Tibetan Plateau.Investigation of the PAHs distribution in Shennongjia regio...Studies on the elevation gradient distribution of polycyclic aromatic hydrocarbons(PAHs)have mainly focused on high-altitude regions like the Tibetan Plateau.Investigation of the PAHs distribution in Shennongjia region and the effects of total organic carbon(TOC),black carbon(BC)and elevation gradient on PAHs distribution are of great practical significance for protecting the Tibetan Plateau’s environment.This study collected soil and peat samples across varying vegetation types and altitudes in Shennongjia.Results showed that theΣ16PAHs concentrations ranged from 15.44 to 199.13 ng/g in surface soil and 300.15 to 555.52 ng/g in surface peat,respectively,both dominated by low molecular weight PAHs(LMW-PAHs),and the distribution line of PAHs in the soil of Shennongjia area is 1500-1700 m.Above 1700 m,PAH concentrations increased with altitude,influenced significantly by TOC and BC,though dependence on BC was stronger than on TOC.However,the dependence of PAHs on BC is higher than TOC.Through soil-air partition coefficient(KSA)and soil fugacity,it is found that the absorption capacity of PAHs is mainly concentrated in Dajiuhu,which is equivalent to a"trap".The ILCRs induced by PAHs in the soil of Shennongjia area are within the safe range.Shennongjia serves as a barrier,preventing pollutant transport from central emission areas to the Tibetan Plateau.Thus,amid tourism development,addressing traffic-related PAH sources,promoting green energy,and controlling air pollutants in central emission areas are vital for ecological protection in Shennongjia and the Tibetan Plateau.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.51576016 and 51476012)
文摘In this study,the particle size-resolved distribution from a China-3 certificated light-duty diesel vehicle was measured by using a portable emission measurement system（PEMS）.In order to examine the influences of vehicle specific power（VSP） and high-altitude operation,measurements were conducted at 8 constant speeds,which ranged from 10 to 80 km/hr at10 km/hr intervals,and two different high altitudes,namely 2200 and 3200 m.The results demonstrated that the numbers of particles in all size ranges decreased significantly as VSP increased when the test vehicle was running at lower speeds（〈 20 km/hr）,while at a moderate speed（between 30 and 60 km/hr）,the particle number was statistically insensitive to increase VSP.Under high-speed cruising conditions,the numbers of ultrafine particles and PM2.5were insensitive to changes in VSP,but the numbers of nanoparticles and PM10 surged considerably.An increase in the operational altitude of the test vehicle resulted in increased particle number emissions at low and high driving speeds;however,particle numbers obtained at moderate speeds decreased as altitude rose.When the test vehicle was running at moderate speeds,particle numbers measured at the two altitudes were very close,except for comparatively higher number concentrations of nanoparticles measured at 2200 m.
基金a Grant No. 15T-1E061 ‘‘Radioecological Monitoring in the Area of the Republic of Armenia’’ 2015–2017, under support of State Committee of Science to the Ministry of Education and Science RA
文摘This paper considers the distribution of technogenic 137Cs and naturally occurring radionuclides:238 U,232 Th and40 R concentrations in soils and 137Cs in atmospheric dry depositions by altitudinal belts of the Aragats mountain massif,Republic of Armenia.Undisturbed soil samples were collected at altitudes from 1000 to 3200 m.For the determination of geochemical variability,two soil sampling campaigns were undertaken.Atmospheric dry depositions were sampled from five stations at1100-3200 m collected onto organic fiber filters between June and December 2016.137Cs activity was measured using a high-purity Germanium detector coupled to a multichannel analyzer(Canberra).Results indicated that specific activity of 137Cs in soils at 1000 m is495-528 Bq m^-2,andat3200 mis10,500-11,470 Bq m^-2.No correlation observed for 137Cs versus naturally occurring radionuclides,which varies in distribution by altitude.Specific activities of 137Cs in dry atmospheric depositions varies from 1.06 at 846 m to2.37 Bq m^-2 per quarter at 3200 m and increases as the altitude increases.Activities of 137Cs in soil and dry atmospheric deposition correlated significantly,and 137Cs activity in soils and atmospheric dry depositions decrease as the absolute altitude decreases.The 50-year effective dose from exposure to 137Cs fallout varies with altitude from 0.007 to 1.42 m Sv.
基金supported by the National Natural Science Foundations of China(No.42377235)the National Key Research and Development Program of China(No.2023YFC3709803)+1 种基金the Open Research Fund of Hubei Key Laboratory of Mine Environmental Pollution Control and Remediation(No.2023XZ103)Hubei Polytechnic University talent introduction project(No.24xjz13R).
文摘Studies on the elevation gradient distribution of polycyclic aromatic hydrocarbons(PAHs)have mainly focused on high-altitude regions like the Tibetan Plateau.Investigation of the PAHs distribution in Shennongjia region and the effects of total organic carbon(TOC),black carbon(BC)and elevation gradient on PAHs distribution are of great practical significance for protecting the Tibetan Plateau’s environment.This study collected soil and peat samples across varying vegetation types and altitudes in Shennongjia.Results showed that theΣ16PAHs concentrations ranged from 15.44 to 199.13 ng/g in surface soil and 300.15 to 555.52 ng/g in surface peat,respectively,both dominated by low molecular weight PAHs(LMW-PAHs),and the distribution line of PAHs in the soil of Shennongjia area is 1500-1700 m.Above 1700 m,PAH concentrations increased with altitude,influenced significantly by TOC and BC,though dependence on BC was stronger than on TOC.However,the dependence of PAHs on BC is higher than TOC.Through soil-air partition coefficient(KSA)and soil fugacity,it is found that the absorption capacity of PAHs is mainly concentrated in Dajiuhu,which is equivalent to a"trap".The ILCRs induced by PAHs in the soil of Shennongjia area are within the safe range.Shennongjia serves as a barrier,preventing pollutant transport from central emission areas to the Tibetan Plateau.Thus,amid tourism development,addressing traffic-related PAH sources,promoting green energy,and controlling air pollutants in central emission areas are vital for ecological protection in Shennongjia and the Tibetan Plateau.
