Size-fractionated particulate matter(PM_(2.5)and PM>_(2.5))was collected at a traffic site in Kanazawa,Japan in a seasonal sampling work in 2020.Nine polycyclic aromatic hydrocarbons(4-to 6-ring PAHs)were determine...Size-fractionated particulate matter(PM_(2.5)and PM>_(2.5))was collected at a traffic site in Kanazawa,Japan in a seasonal sampling work in 2020.Nine polycyclic aromatic hydrocarbons(4-to 6-ring PAHs)were determined in fine and coarse particles.The gas/particle partitioning coefficients(K_(p))of the PAHs were calculated from the supercooled liquid vapour pressure and octanol-air partitioning coefficient based on the relationships obtained in previous traffic pollution-related studies.Gaseous PAHs were estimated by K_(p) and the concentrations of PM and particulate PAHs.The concentrations of total PAHs were 32.5,320.1 and 5646.2 pg/m^(3) in the PM>_(2.5),PM_(2.5) and gas phases,respectively.Significant seasonal trends in PAHs were observed(particle phase:lowest in summer,gas phase:lowest in spring,particle and gas phase:lowest in spring).Compared to 2019,the total PAH concentrations(in particles)decreased in 2020,especially in spring and summer,which might be due to reduced traffic trips during the COVID-19 outbreak.The incremental lifetime cancer risk(ILCR)calculated from the toxic equivalent concentrations relative to benzo[a]pyrene(BaP_(eq))was lower than the acceptable limit issued by the US Environmental Protection Agency,indicating a low cancer risk in long-term exposure to current PAH levels.It is notable that gaseous PAHs considerably contributed to BaP_(eq) and ILCR(over 50%),which highlighted the significance of gaseous PAH monitoring for public health protection.This low-cost estimation method for gaseous PAHs can be expected to reliably and conveniently obtain PAH concentrations as a surrogate for traditional sampling in the future work.展开更多
The fate of Polycyclic Aromatic Hydrocarbons （PAHs） residing in the atmosphere has received enormous attention in recent years due to their mutagenic and carcinogenic risks on human health. In this context, the stab...The fate of Polycyclic Aromatic Hydrocarbons （PAHs） residing in the atmosphere has received enormous attention in recent years due to their mutagenic and carcinogenic risks on human health. In this context, the stability of pyrene （as a representative PAHs） on quartz, alumina, montmorillonite, kaolinite, humic acid and quartz coated with sorbed humic acid was investigated at controlled relative humidity （RH： i.e. 5% and 30%） without light irradiation in order to detect the presence of catalytic effect of mineral surface on PAHs decomposition. The stability of pyrene was found to depend strongly on the physicochemical properties of the substrates. Quartz showed a strong catalytic effect for the decomposition of pyrene even though it was coated with sorbed humic acid. Pyrene sorbed on montmorillonite and humic acid remained stable during the experimental period （i.e. 3 days）. Moisture in the experimental cell also affected the stability of pyrene in particular minerals. Especially, pyrene sorbed on alumina was rapidly decomposed at higher RH. However, there were almost no effect in the case of quartz, kaolinite and humic acid. Depending on the physicochemical properties of aerosols and RH, PAHs associated with minerals in the atmosphere would be decomposed and/or stably reside in the atmosphere.展开更多
Arsenic is usually associated with sulphide minerals formed in the geothermal environment. However, sulphide minerals are prone to dissolution after contact with meteoric water under surface oxidizing conditions. Seco...Arsenic is usually associated with sulphide minerals formed in the geothermal environment. However, sulphide minerals are prone to dissolution after contact with meteoric water under surface oxidizing conditions. Secondary precipitates that form from the dissolution of the primary sulfides exert a greater influence on arsenic mobility in the geothermal environment. Fe-hydroxides have very good affinity with dissolved arsenate and are stable under most surface oxidizing conditions. Both amorphous silica directly precipitated from geothermal fluids and possibly a kaolinite alteration can host a small significant amount of arsenic. These silicates are also more stable under a wide range ofpH and redox conditions.展开更多
Polycyclic aromatic hydrocarbons(PAHs) are ubiquitous in the atmosphere and they mostly stem from the imperfect combustion of fossil fuels and biofuels.PAHs are inherently associated with homogenous fine particles or ...Polycyclic aromatic hydrocarbons(PAHs) are ubiquitous in the atmosphere and they mostly stem from the imperfect combustion of fossil fuels and biofuels.PAHs are inherently associated with homogenous fine particles or distributed to different-sized particles during the aging of air masses.PAHs carried by fine particles undergo a long-range transport to remote areas while those adsorbed on coarse particles have a shorter lifetime in ambient air.More importantly, PAHs with higher molecular weights tend to be bound with finer particles and can deeply enter the lungs, posing severe health risks to humans.Thus, the environmental fate and health effects of particulate PAHs are strongly size-dependent.This review summarizes the size distributions of particulate PAHs freshly emitted from combustion sources as well as the distribution patterns of PAHs in ambient particles.It was found that PAHs from stationary sources are primarily bound to fine particles, which are slightly larger than particles to which PAHs from mobile sources are bound.In ambient air, particulate PAHs are distributed in larger size modes than those in the combustion fume, and the particle size decreases with PAH molecular weight increasing.The relevant mechanisms and influencing factors of particle size distribution changes are illustrated in this article, which are essentially attributed to combustion and ambient temperature as well as the physical and chemical properties of PAHs.Overall, the study on the particle size distribution of PAHs will contribute for a full understanding of the origin, atmospheric behaviors and health effects of particulate PAHs.展开更多
This study encompassed the regular observation of nine polycyclic aromatic hydrocarbons(PAHs)and three nitro-PAHs(NPAHs)in particulate matter(PM)in Shanghai in summer and winter from 2010 to 2018.The results showed th...This study encompassed the regular observation of nine polycyclic aromatic hydrocarbons(PAHs)and three nitro-PAHs(NPAHs)in particulate matter(PM)in Shanghai in summer and winter from 2010 to 2018.The results showed that the mean concentrations of∑PAHs in summer decreased by 24.7%in 2013 and 18.1%in 2017 but increased by 10.2%in 2015 compared to the data in 2010.However,the mean concentrations of∑PAHs in winter decreased by 39.7%from 2010(12.8±4.55 ng/m^3)to 2018(7.72±3.33 ng/m^3),and the mean concentrations of 1-nitropyrene in winter decreased by 79.0%from 2010(42.3±16.1 pg/m^3)to 2018(8.90±2.09 pg/m^3).Correlation analysis with meteorological conditions revealed that the PAH and NPAH concentrations were both influenced by ambient temperature.The diagnostic ratios of PAHs and factor analysis showed that they were mainly affected by traffic emissions with some coal and/or biomass combustion.The ratio of 2-nitrofluoranthene to 2-nitropyrene was near 10,which indicated that the OH radical-initiated reaction was the main pathway leading to their secondary formation.Moreover,backward trajectories revealed different air mass routes in each sampling period,indicating a high possibility of source effects from the northern area in winter in addition to local and surrounding influences.Meanwhile,the mean total benzo[a]pyrene-equivalent concentrations in Shanghai in winter decreased by 50.8%from 2010(1860±645 pg/m^3)to 2018(916±363 pg/m^3).These results indicated the positive effects of the various policies and regulations issued by Chinese authorities.展开更多
The transport of ye been investigated numerica Ilow sand over mountain regions in the presence of internal gravity waves has y. The motion of yellow sand particles has been simulated in a Lagrangian frame of reference...The transport of ye been investigated numerica Ilow sand over mountain regions in the presence of internal gravity waves has y. The motion of yellow sand particles has been simulated in a Lagrangian frame of reference by solving the time-dependent Reynolds averaged Navier-Stokes equations. An implicit time integration in a fitted body grid arrangement was used to simulate the stratified flow over an isolated ideally bell-shaped mountain. The transport and deposition of particles of various sizes, and of the altitudes where particles were released have been analyzed. Particular attention was given to transport patterns of different sized particles in various atmospheric conditions. The results show that the particle size and the release altitude are both important factors in determining the trajectories of the particles. Small particles tend to be transported a long distance over the mountains, whereas heavier particles settle down around the release source. Due to the existence of an internal gravity wave, the particle release altitude affects the trajectory of the particles. The analysis and results provide a very useful tool for the study of atmospheric flow and transport of pollutants over real topographies.展开更多
Airborne bacteria were measured when a dust storm passed Beijing in spring 2012 with a focus on cell concentration, viability and TSA- and R2A-cultured strain composition. The concentration varied at an order of 10^7 ...Airborne bacteria were measured when a dust storm passed Beijing in spring 2012 with a focus on cell concentration, viability and TSA- and R2A-cultured strain composition. The concentration varied at an order of 10^7 cells/m3 with dust loading （demonstrated with PM10） and they had a very close correlation （RT2 = 0.91, p 〈 0.01）. At the time of highest PM10 of 652 μg/m3, the bacterial concentration reached 1.4 × 10^8 cells/m3, which was larger than that before and after the dust event by one order. Bacterial viability, the ratio of number concentration of viable cells to total cells, was 32%-64% and smaller in the dust plume than that before the dust arrival. Bacterial strains from the culture ranged between 2.5 × 10^4 and 4.6 × 10^5 CFU/m3 and no correlation with PM10 was determined. Their composition was different before and after the dust arrival according to 16S rRNA gene sequences and strains belong to Actinomycetes and Firmicutes were the majority in the dust samples.展开更多
The effect of short-term exposure to polycyclic aromatic hydrocarbons(PAHs)on the respiratory system among healthy residents is unclear.Beijing and Baoding are typical polluted cities in China,and there is little rese...The effect of short-term exposure to polycyclic aromatic hydrocarbons(PAHs)on the respiratory system among healthy residents is unclear.Beijing and Baoding are typical polluted cities in China,and there is little research on PAH exposure and its health effects at the individual level.Fourteen healthy female office workers were recruited in urban Beijing and Baoding,China,in 2019.The personal exposure to fine particulate matter(PM_(2.5))-bound PAHs and lung function were seasonally monitored.The relationships between PAH exposure and lung function were determined by a generalized mixed linear model.Subjects were exposed to high levels of PAH,in which the benzo[a]pyrene(BaP)level(1.26 ng/m^(3))was over than Chinese national indoor standard(1 ng/m^(3)).All PAHs concentration was higher in winter than that in summer and autumn.Only benz[a]anthracene(BaA)and chrysene(Chr)exposure showed weak relations with decreased lung function,i.e.,a 0.58% and 0.73% decrease in peak expiratory flow at lag 2 day,respectively(p<0.05).PAHs may not be suitable exposure indicators for short-term change in lung function.Our findings highlight the importance of reducing PAH pollution for public respiratory health protection in heavy-polluted cities of China.This pilot study also provides experience on personal PAH assessment such as estimation of the number of repeated measurements required,which is helpful to determine the relationship between PAH exposure and health effect.展开更多
The Preston＇s method is considered as one of the most commonly employed methods to measure the wall shear stress. However, it is only possible to determine the wall shear stress from measured pressure differences of ...The Preston＇s method is considered as one of the most commonly employed methods to measure the wall shear stress. However, it is only possible to determine the wall shear stress from measured pressure differences of the Preston tube and undisturbed static pressure, combined with calibration curves, which depend on the Preston tube diameter, fluid density, and viscosity. Since its invention, no significant advancement in theory has been made, and calibration curves proposed by Preston, Patel and Bechert are still in use. In the present study, a need to measure surface shear stress over a circular cylinder prompted us to develop our original Preston tube system. The developed system has been calibrated by measuring the wall shear stress in the fully developed turbulent flow regime in a circular pipe. The present results generally confirm the previously reported calibration curves. A slight modification of the coefficients in the calibration equation shows further improvement.展开更多
Using the combined approach of questionnaire and semi-structured interview, this study aims to exam- ine the characteristics of a small agricultural business, and benefits perceived by the participants, and challenges...Using the combined approach of questionnaire and semi-structured interview, this study aims to exam- ine the characteristics of a small agricultural business, and benefits perceived by the participants, and challenges. The ＂multi-industrial system＂ regional initiative for creating new high-value-added businesses project encourages rural residents to commercialize their surplus agricultural and forestry products, such as pickled or dried wild and cultivated plants. Knowledgeable older people, women farmers in particular, are motivated to market their vegeta- bles directly to the urban market, and their home-processed wild plants to local restaurants and hotels. It found that the older people involved in the business considered that their health and economic situation had been improved through participating in vegetable cultivation and sales. Some lessons from this case study can be identified： the empowerment of older people and women farmers, through active interaction with the market and learning new technologies, including internet-based information search strategies.展开更多
The long sediment core BDP98 obtained from Lake Baikal was analyzed in order to discuss the periodicity of glacial cycles in the terrestrial climatic record of the past 2.6 Ma.Spectral analysis shows that the Baikal g...The long sediment core BDP98 obtained from Lake Baikal was analyzed in order to discuss the periodicity of glacial cycles in the terrestrial climatic record of the past 2.6 Ma.Spectral analysis shows that the Baikal grain size record has been dominated by orbit-related cycles with periods of about100 ka,41 ka,and 23 ka,similar to those in the marine isotope record.However,there are some notable differences between the Baikal and oceanic records.In the marine isotope record,the 41 ka cycle was dominant before 1 Ma and the 100 ka cycle became significant only afterward.Conversely,in the Baikal record,the 100 ka period has appeared continuously throughout the past 2.6 Ma,and no appreciable shift in period is detected.These results suggest that the terrestrial climatic response to orbital forcing,as imprinted in the Baikal sediment,is different from the oceanic response.The 100 ka cycle detected in the Baikal record from before 1 Ma may be attributable to relatively long interglacials with skipping of two or three 41 ka obliquity cycles.This result may support the hypothesis that the 100 ka cycle is paced by the obliquity cycle.展开更多
Sediment information is closely related to a lake-catchment system.Lake Baikal and Lake Khuvsgul in the Baikal depression have shown different sedimentary trends during the past 800 ka;the sediment discharge(sedimenta...Sediment information is closely related to a lake-catchment system.Lake Baikal and Lake Khuvsgul in the Baikal depression have shown different sedimentary trends during the past 800 ka;the sediment discharge(sedimentation rate) in Baikal basically followed the global climatic change,whereas that in Khuvsgul did not always do so.An elementary mathematical model is used to explain the difference,considering changes in the catchment area and water level.Numerical calculations based on the model suggest that sedimentary conditions are closely related to changes in the water level and erosion area,which probably had a significant influence on Lake Khuvsgul and little influence on Lake Baikal.展开更多
HDP09 core drilled in Lake Khuvsgul,Mongoria,at 50°52'48 'N,100°26'30' E where the water depth is 222.25 m reached to the depth of ~60 m below lake floor in 2006.The bottom part of the core c...HDP09 core drilled in Lake Khuvsgul,Mongoria,at 50°52'48 'N,100°26'30' E where the water depth is 222.25 m reached to the depth of ~60 m below lake floor in 2006.The bottom part of the core consists of alkali basalt.This basalt consists of the basement of the lake Khuvsgul based on its bulk chemistry and core position plotted on the seismic profile.K-Ar age of the basalt is(8.5±0.2) Ma,which is concordant with the on-land basalt distributed in the eastern part of the lake,and implies the maximum age of the Lake Khuvsgul formation.展开更多
A three-year sampling campaign was conducted at a roadside air pollution monitoring station in the urban area of Kanazawa, Japan. Due to a new emission regulation, PAHs levels decreased over the sampling campaign, exh...A three-year sampling campaign was conducted at a roadside air pollution monitoring station in the urban area of Kanazawa, Japan. Due to a new emission regulation, PAHs levels decreased over the sampling campaign, exhibiting values of 706 ± 413 pg/m^(3) in 2017, 559 ±384 pg/m^(3) in 2018, and 473 ± 234 pg/m^(3) in 2019. In each year, similar seasonal variations in PAHs levels were observed, with higher levels observed in winter and lower levels in summer. Among the PAHs isomer ratios, we observed that the ratio of benzo[b]fluoranthene(BbF) and benzo[k]fluoranthene(BkF), [Bb F]/([BbF] + [BkF]), and the ratio of indeno[1,2,3-cd]pyrene(IDP) and benzo[ghi]perylene(BgPe), [IDP]/([BgPe] + [IDP]), showed stability over the sampling campaign and were less affected by the new emission regulation, seasonal variations, and regional characteristics. When using the combined ratio ranges of 0.66-0.80([Bb F]/[BbF] + [BkF]) and 0.26-0.49([IDP]/[Bg Pe] + [IDP]), traffic emissions were clearly distinguished from other PAHs emission sources. Principal component analysis(PCA) and positive matrix factorization(PMF) were also performed to further analyse the characteristics of traffic-related PAHs. Overall, this study affirmed the effectiveness of the new emission regulation in the reduction of PAHs emissions and provided a combined range for identifying PAHs traffic emission sources.展开更多
The characteristics of stratified flow over an isolated mountain ridge have been investigated numerically. The two-dimensional model equations, based on the time-dependent Reynolds averaged Navier- Stokes equations, a...The characteristics of stratified flow over an isolated mountain ridge have been investigated numerically. The two-dimensional model equations, based on the time-dependent Reynolds averaged Navier- Stokes equations, are solved numerically using an implicit time integration in a fitted body grid arrangement to simulate stratified flow over an isolated ideally bell-shaped mountain. The simulation results are in good agreement with the existing corresponding analytical and approximate solutions. It is shown that for atmospheric conditions where non-hydrostatic effects become dominant, the model is able to reproduce typical flow features. The dispersion characteristics of gaseous pollutants in the stratified flow have also been studied. The dispersion patterns for two typical atmospheric conditions are compared. The results show that the presence of a gravity wave causes vertical stratification of the pollutant concentration and affects the diffusive characteristics of the pollutants.展开更多
基金supported by the Bilateral Open Partnership Joint Research Projects of the Japan Society for the Promotion of Science,Japan(No.JPJSBP120219914)the CHOZEN Project of Kanazawa University,Japan(2019)the Cooperative Research Programs of Institute of Nature and Environmental Technology,Kanazawa University,Japan(22002,22013,22007)。
文摘Size-fractionated particulate matter(PM_(2.5)and PM>_(2.5))was collected at a traffic site in Kanazawa,Japan in a seasonal sampling work in 2020.Nine polycyclic aromatic hydrocarbons(4-to 6-ring PAHs)were determined in fine and coarse particles.The gas/particle partitioning coefficients(K_(p))of the PAHs were calculated from the supercooled liquid vapour pressure and octanol-air partitioning coefficient based on the relationships obtained in previous traffic pollution-related studies.Gaseous PAHs were estimated by K_(p) and the concentrations of PM and particulate PAHs.The concentrations of total PAHs were 32.5,320.1 and 5646.2 pg/m^(3) in the PM>_(2.5),PM_(2.5) and gas phases,respectively.Significant seasonal trends in PAHs were observed(particle phase:lowest in summer,gas phase:lowest in spring,particle and gas phase:lowest in spring).Compared to 2019,the total PAH concentrations(in particles)decreased in 2020,especially in spring and summer,which might be due to reduced traffic trips during the COVID-19 outbreak.The incremental lifetime cancer risk(ILCR)calculated from the toxic equivalent concentrations relative to benzo[a]pyrene(BaP_(eq))was lower than the acceptable limit issued by the US Environmental Protection Agency,indicating a low cancer risk in long-term exposure to current PAH levels.It is notable that gaseous PAHs considerably contributed to BaP_(eq) and ILCR(over 50%),which highlighted the significance of gaseous PAH monitoring for public health protection.This low-cost estimation method for gaseous PAHs can be expected to reliably and conveniently obtain PAH concentrations as a surrogate for traditional sampling in the future work.
文摘The fate of Polycyclic Aromatic Hydrocarbons （PAHs） residing in the atmosphere has received enormous attention in recent years due to their mutagenic and carcinogenic risks on human health. In this context, the stability of pyrene （as a representative PAHs） on quartz, alumina, montmorillonite, kaolinite, humic acid and quartz coated with sorbed humic acid was investigated at controlled relative humidity （RH： i.e. 5% and 30%） without light irradiation in order to detect the presence of catalytic effect of mineral surface on PAHs decomposition. The stability of pyrene was found to depend strongly on the physicochemical properties of the substrates. Quartz showed a strong catalytic effect for the decomposition of pyrene even though it was coated with sorbed humic acid. Pyrene sorbed on montmorillonite and humic acid remained stable during the experimental period （i.e. 3 days）. Moisture in the experimental cell also affected the stability of pyrene in particular minerals. Especially, pyrene sorbed on alumina was rapidly decomposed at higher RH. However, there were almost no effect in the case of quartz, kaolinite and humic acid. Depending on the physicochemical properties of aerosols and RH, PAHs associated with minerals in the atmosphere would be decomposed and/or stably reside in the atmosphere.
文摘Arsenic is usually associated with sulphide minerals formed in the geothermal environment. However, sulphide minerals are prone to dissolution after contact with meteoric water under surface oxidizing conditions. Secondary precipitates that form from the dissolution of the primary sulfides exert a greater influence on arsenic mobility in the geothermal environment. Fe-hydroxides have very good affinity with dissolved arsenate and are stable under most surface oxidizing conditions. Both amorphous silica directly precipitated from geothermal fluids and possibly a kaolinite alteration can host a small significant amount of arsenic. These silicates are also more stable under a wide range ofpH and redox conditions.
基金supported in part by a Grant in Aid for Scientific Research (Nos.17K08388 and 17H06283) from the Ministry of Education, Culture, Sports, Science and Technologythe cooperative research program of Institute of Nature and Environmental Technology, Kanazawa University (Nos.16007, 17002 and 17037).
文摘Polycyclic aromatic hydrocarbons(PAHs) are ubiquitous in the atmosphere and they mostly stem from the imperfect combustion of fossil fuels and biofuels.PAHs are inherently associated with homogenous fine particles or distributed to different-sized particles during the aging of air masses.PAHs carried by fine particles undergo a long-range transport to remote areas while those adsorbed on coarse particles have a shorter lifetime in ambient air.More importantly, PAHs with higher molecular weights tend to be bound with finer particles and can deeply enter the lungs, posing severe health risks to humans.Thus, the environmental fate and health effects of particulate PAHs are strongly size-dependent.This review summarizes the size distributions of particulate PAHs freshly emitted from combustion sources as well as the distribution patterns of PAHs in ambient particles.It was found that PAHs from stationary sources are primarily bound to fine particles, which are slightly larger than particles to which PAHs from mobile sources are bound.In ambient air, particulate PAHs are distributed in larger size modes than those in the combustion fume, and the particle size decreases with PAH molecular weight increasing.The relevant mechanisms and influencing factors of particle size distribution changes are illustrated in this article, which are essentially attributed to combustion and ambient temperature as well as the physical and chemical properties of PAHs.Overall, the study on the particle size distribution of PAHs will contribute for a full understanding of the origin, atmospheric behaviors and health effects of particulate PAHs.
基金the Ministry of Education,Culture,Sports,Science and Technology,Japan(17K08388)the Sasakawa Scientific Research Grant(2020–3008)from The Japan Science Society+3 种基金the Environment Research and Technology Development Fund(5–1951)of the Environmental Restoration and Conservation Agency of Japanthe Sumitomo Foundation,Japan(183115)the CHOZEN Project of Kanazawa University,Japanthe cooperative research programs of Institute of Nature and Environmental Technology,Kanazawa University,Japan(20016,20062)。
文摘This study encompassed the regular observation of nine polycyclic aromatic hydrocarbons(PAHs)and three nitro-PAHs(NPAHs)in particulate matter(PM)in Shanghai in summer and winter from 2010 to 2018.The results showed that the mean concentrations of∑PAHs in summer decreased by 24.7%in 2013 and 18.1%in 2017 but increased by 10.2%in 2015 compared to the data in 2010.However,the mean concentrations of∑PAHs in winter decreased by 39.7%from 2010(12.8±4.55 ng/m^3)to 2018(7.72±3.33 ng/m^3),and the mean concentrations of 1-nitropyrene in winter decreased by 79.0%from 2010(42.3±16.1 pg/m^3)to 2018(8.90±2.09 pg/m^3).Correlation analysis with meteorological conditions revealed that the PAH and NPAH concentrations were both influenced by ambient temperature.The diagnostic ratios of PAHs and factor analysis showed that they were mainly affected by traffic emissions with some coal and/or biomass combustion.The ratio of 2-nitrofluoranthene to 2-nitropyrene was near 10,which indicated that the OH radical-initiated reaction was the main pathway leading to their secondary formation.Moreover,backward trajectories revealed different air mass routes in each sampling period,indicating a high possibility of source effects from the northern area in winter in addition to local and surrounding influences.Meanwhile,the mean total benzo[a]pyrene-equivalent concentrations in Shanghai in winter decreased by 50.8%from 2010(1860±645 pg/m^3)to 2018(916±363 pg/m^3).These results indicated the positive effects of the various policies and regulations issued by Chinese authorities.
基金the Scientific Foundation for Returned Overseas Chinese Scholars, Ministry of Education of China
文摘The transport of ye been investigated numerica Ilow sand over mountain regions in the presence of internal gravity waves has y. The motion of yellow sand particles has been simulated in a Lagrangian frame of reference by solving the time-dependent Reynolds averaged Navier-Stokes equations. An implicit time integration in a fitted body grid arrangement was used to simulate the stratified flow over an isolated ideally bell-shaped mountain. The transport and deposition of particles of various sizes, and of the altitudes where particles were released have been analyzed. Particular attention was given to transport patterns of different sized particles in various atmospheric conditions. The results show that the particle size and the release altitude are both important factors in determining the trajectories of the particles. Small particles tend to be transported a long distance over the mountains, whereas heavier particles settle down around the release source. Due to the existence of an internal gravity wave, the particle release altitude affects the trajectory of the particles. The analysis and results provide a very useful tool for the study of atmospheric flow and transport of pollutants over real topographies.
基金the support of the Sumitomo Environmental Foundation(103096) of 2011–2012the Grant-in-Aid for Exploratory Research of JSPS(15K12192)the National Natural Science Foundation of China(No: 31470232)
文摘Airborne bacteria were measured when a dust storm passed Beijing in spring 2012 with a focus on cell concentration, viability and TSA- and R2A-cultured strain composition. The concentration varied at an order of 10^7 cells/m3 with dust loading （demonstrated with PM10） and they had a very close correlation （RT2 = 0.91, p 〈 0.01）. At the time of highest PM10 of 652 μg/m3, the bacterial concentration reached 1.4 × 10^8 cells/m3, which was larger than that before and after the dust event by one order. Bacterial viability, the ratio of number concentration of viable cells to total cells, was 32%-64% and smaller in the dust plume than that before the dust arrival. Bacterial strains from the culture ranged between 2.5 × 10^4 and 4.6 × 10^5 CFU/m3 and no correlation with PM10 was determined. Their composition was different before and after the dust arrival according to 16S rRNA gene sequences and strains belong to Actinomycetes and Firmicutes were the majority in the dust samples.
基金supported by the Sasakawa Scientific Research Grant(2021-6039)from The Japan Science Societythe Bilateral Open Partnership Joint Research Projects of the Japan Society for the Promotion of Science,Japan(JPJSBP120219914)+1 种基金the CHOZEN Project of Kanazawa University,Japanthe cooperative research programs of the Institute of Nature and Environmental Technology,Kanazawa University,Japan.
文摘The effect of short-term exposure to polycyclic aromatic hydrocarbons(PAHs)on the respiratory system among healthy residents is unclear.Beijing and Baoding are typical polluted cities in China,and there is little research on PAH exposure and its health effects at the individual level.Fourteen healthy female office workers were recruited in urban Beijing and Baoding,China,in 2019.The personal exposure to fine particulate matter(PM_(2.5))-bound PAHs and lung function were seasonally monitored.The relationships between PAH exposure and lung function were determined by a generalized mixed linear model.Subjects were exposed to high levels of PAH,in which the benzo[a]pyrene(BaP)level(1.26 ng/m^(3))was over than Chinese national indoor standard(1 ng/m^(3)).All PAHs concentration was higher in winter than that in summer and autumn.Only benz[a]anthracene(BaA)and chrysene(Chr)exposure showed weak relations with decreased lung function,i.e.,a 0.58% and 0.73% decrease in peak expiratory flow at lag 2 day,respectively(p<0.05).PAHs may not be suitable exposure indicators for short-term change in lung function.Our findings highlight the importance of reducing PAH pollution for public respiratory health protection in heavy-polluted cities of China.This pilot study also provides experience on personal PAH assessment such as estimation of the number of repeated measurements required,which is helpful to determine the relationship between PAH exposure and health effect.
文摘The Preston＇s method is considered as one of the most commonly employed methods to measure the wall shear stress. However, it is only possible to determine the wall shear stress from measured pressure differences of the Preston tube and undisturbed static pressure, combined with calibration curves, which depend on the Preston tube diameter, fluid density, and viscosity. Since its invention, no significant advancement in theory has been made, and calibration curves proposed by Preston, Patel and Bechert are still in use. In the present study, a need to measure surface shear stress over a circular cylinder prompted us to develop our original Preston tube system. The developed system has been calibrated by measuring the wall shear stress in the fully developed turbulent flow regime in a circular pipe. The present results generally confirm the previously reported calibration curves. A slight modification of the coefficients in the calibration equation shows further improvement.
基金UNU-IAS Operating Unit of Ishikawa Kanazawa for this study’s field surveyThe cooperative research program of Institute of Nature and Environmental Technology,Kanazawa University(No.29,2015)
文摘Using the combined approach of questionnaire and semi-structured interview, this study aims to exam- ine the characteristics of a small agricultural business, and benefits perceived by the participants, and challenges. The ＂multi-industrial system＂ regional initiative for creating new high-value-added businesses project encourages rural residents to commercialize their surplus agricultural and forestry products, such as pickled or dried wild and cultivated plants. Knowledgeable older people, women farmers in particular, are motivated to market their vegeta- bles directly to the urban market, and their home-processed wild plants to local restaurants and hotels. It found that the older people involved in the business considered that their health and economic situation had been improved through participating in vegetable cultivation and sales. Some lessons from this case study can be identified： the empowerment of older people and women farmers, through active interaction with the market and learning new technologies, including internet-based information search strategies.
基金Grants-in-Aid for Scientific Research from Ministry of Education,Science and Culture(Japan)to K.Kashiwaya[(A2)20253002]
文摘The long sediment core BDP98 obtained from Lake Baikal was analyzed in order to discuss the periodicity of glacial cycles in the terrestrial climatic record of the past 2.6 Ma.Spectral analysis shows that the Baikal grain size record has been dominated by orbit-related cycles with periods of about100 ka,41 ka,and 23 ka,similar to those in the marine isotope record.However,there are some notable differences between the Baikal and oceanic records.In the marine isotope record,the 41 ka cycle was dominant before 1 Ma and the 100 ka cycle became significant only afterward.Conversely,in the Baikal record,the 100 ka period has appeared continuously throughout the past 2.6 Ma,and no appreciable shift in period is detected.These results suggest that the terrestrial climatic response to orbital forcing,as imprinted in the Baikal sediment,is different from the oceanic response.The 100 ka cycle detected in the Baikal record from before 1 Ma may be attributable to relatively long interglacials with skipping of two or three 41 ka obliquity cycles.This result may support the hypothesis that the 100 ka cycle is paced by the obliquity cycle.
基金Grants-in-Aid for Scientific Research from Ministry of Education,Science and Culture(Japan)to K.Kashiwaya[(A2)20253002]
文摘Sediment information is closely related to a lake-catchment system.Lake Baikal and Lake Khuvsgul in the Baikal depression have shown different sedimentary trends during the past 800 ka;the sediment discharge(sedimentation rate) in Baikal basically followed the global climatic change,whereas that in Khuvsgul did not always do so.An elementary mathematical model is used to explain the difference,considering changes in the catchment area and water level.Numerical calculations based on the model suggest that sedimentary conditions are closely related to changes in the water level and erosion area,which probably had a significant influence on Lake Khuvsgul and little influence on Lake Baikal.
基金The Research Fund from Kanazawa University and Grants-in-Aid for Scientific Research from Japanese Society for the promotion of Science(K.Kashiwaya[(A2)20253002])
文摘HDP09 core drilled in Lake Khuvsgul,Mongoria,at 50°52'48 'N,100°26'30' E where the water depth is 222.25 m reached to the depth of ~60 m below lake floor in 2006.The bottom part of the core consists of alkali basalt.This basalt consists of the basement of the lake Khuvsgul based on its bulk chemistry and core position plotted on the seismic profile.K-Ar age of the basalt is(8.5±0.2) Ma,which is concordant with the on-land basalt distributed in the eastern part of the lake,and implies the maximum age of the Lake Khuvsgul formation.
基金supported by the Bilateral Open Partnership Joint Research Projects of the Japan Society for the Promotion of Science, Japan (JPJSBP120219914)the Environment Research and Technology Development Fund (5-1951) of the Environmental Restoration and Conservation Agency of Japan+1 种基金the CHOZEN Project of Kanazawa University, Japanthe cooperative research programs of Institute of Nature and Environmental Technology, Kanazawa University, Japan (21001)。
文摘A three-year sampling campaign was conducted at a roadside air pollution monitoring station in the urban area of Kanazawa, Japan. Due to a new emission regulation, PAHs levels decreased over the sampling campaign, exhibiting values of 706 ± 413 pg/m^(3) in 2017, 559 ±384 pg/m^(3) in 2018, and 473 ± 234 pg/m^(3) in 2019. In each year, similar seasonal variations in PAHs levels were observed, with higher levels observed in winter and lower levels in summer. Among the PAHs isomer ratios, we observed that the ratio of benzo[b]fluoranthene(BbF) and benzo[k]fluoranthene(BkF), [Bb F]/([BbF] + [BkF]), and the ratio of indeno[1,2,3-cd]pyrene(IDP) and benzo[ghi]perylene(BgPe), [IDP]/([BgPe] + [IDP]), showed stability over the sampling campaign and were less affected by the new emission regulation, seasonal variations, and regional characteristics. When using the combined ratio ranges of 0.66-0.80([Bb F]/[BbF] + [BkF]) and 0.26-0.49([IDP]/[Bg Pe] + [IDP]), traffic emissions were clearly distinguished from other PAHs emission sources. Principal component analysis(PCA) and positive matrix factorization(PMF) were also performed to further analyse the characteristics of traffic-related PAHs. Overall, this study affirmed the effectiveness of the new emission regulation in the reduction of PAHs emissions and provided a combined range for identifying PAHs traffic emission sources.
基金the Scientific Foundation for Returned Overseas Chinese Scholars, Ministry of Education of China
文摘The characteristics of stratified flow over an isolated mountain ridge have been investigated numerically. The two-dimensional model equations, based on the time-dependent Reynolds averaged Navier- Stokes equations, are solved numerically using an implicit time integration in a fitted body grid arrangement to simulate stratified flow over an isolated ideally bell-shaped mountain. The simulation results are in good agreement with the existing corresponding analytical and approximate solutions. It is shown that for atmospheric conditions where non-hydrostatic effects become dominant, the model is able to reproduce typical flow features. The dispersion characteristics of gaseous pollutants in the stratified flow have also been studied. The dispersion patterns for two typical atmospheric conditions are compared. The results show that the presence of a gravity wave causes vertical stratification of the pollutant concentration and affects the diffusive characteristics of the pollutants.
