The total dust column and the dry deposition flux were calculated based on the optical properties that were measured by a shipboard sun photometer POM-01 MK II in a cloud-free and nonfrontal dust condition on 24 April...The total dust column and the dry deposition flux were calculated based on the optical properties that were measured by a shipboard sun photometer POM-01 MK II in a cloud-free and nonfrontal dust condition on 24 April 2006. The total dust column was calculated by using an integration method of the particle size distribution; the mean value was 1.42±0.30 g m 2. A linear correlation between the total dust column and the aerosol optical depth (AOD) with a linear factor of 2.7 g m 2 over the Sahara was applied to calculate the total dust column in this study; the results were lower than these calculated by the integration method. A reasonable factor of 3.2 g m^-2 was achieved by minimizing the standard deviation (SD) of the two methods. The two layers model, which includes the deposition processes of turbulent transfer, Brownian diffusion, impaction and gravitational settling over the sea's surface, was used to calculate the dry deposition flux; the mean value was 5.05±2.49 μg m^-2 s^-1. A correlation among the total dust column, dry deposition flux, AOD, and effective radius was discussed. The correlation between the total better than that between dust column and the AOD was the total dust column and the effective radius; however, the correlation between the dry deposition flux and the effective radius was better than that between the dry deposition flux and the AOD.展开更多
The regional air quality modeling system Regional Atmospheric Modeling System–Community Multiscale Air Quality was applied to estimate the spatial distribution and seasonal variation in nitrogen wet deposition over E...The regional air quality modeling system Regional Atmospheric Modeling System–Community Multiscale Air Quality was applied to estimate the spatial distribution and seasonal variation in nitrogen wet deposition over East Asia in 2010. The simulated results were evaluated by comparing modeled precipitation rates and ion concentrations, such as ammonium(NH_4~+), nitrate(NO_3^-), and sulfate, in rainwater, against observations obtained from Acid Deposition Monitoring Network in East Asia and meteorological stations in China. Comparison of simulated and observed precipitation showed that the modeling system can reproduce seasonal precipitation patterns reasonably well. For major ion species, the simulated results in most cases were in good agreement with those observed. Analysis of the modeled wet deposition distributions indicated that China experiences noticeable variation in wet deposition patterns throughout the year. Nitrogen wet deposition(NH_4~+ + NO_3^-) during summer and spring accounted for 71% of the annual total(3.9 Tg N yr^(-1)), including 42.7% in summer. Precipitation plays a larger role in the seasonal variation of wet deposition; whereas, aerosol concentrations affect its distribution patterns. In China, the amount of annual nitrogen wet deposition ranged from 1 to 18 kg N ha^(-1). Nitrogen in wet deposition was mainly in the form of NH_4~+, accounting for 65.76% of the total amount, and the molar ratio of NH_4~+∕NO_3^- was mostly more than 1, indicating a relatively larger effect from agricultural activities.展开更多
Stratospheric aerosol extinction profiles are retrieved from Scanning Imaging Absorption Spectrometer for Atmospheric Cartography(SCIAMACHY) limb scatter measurements.In the process of retrieval,the SCIATRAN radiative...Stratospheric aerosol extinction profiles are retrieved from Scanning Imaging Absorption Spectrometer for Atmospheric Cartography(SCIAMACHY) limb scatter measurements.In the process of retrieval,the SCIATRAN radiative transfer model is used to simulate the limb scattering radiation received by the SCIAMACHY instrument,and an optimal estimation algorithm is used to calculate the aerosol extinction profiles.Sensitivity analyses are performed to investigate the impact of the surface albedo on the accuracy of the retrieved aerosol extinction profiles in the northern midlatitudes.It is found that the errors resulting from the bias of the assumed surface albedo in the retrieval are generally below 6%.The retrieved SCIAMACHY aerosol extinction profiles are compared with corresponding Stratospheric Aerosol and Gas Experiment(SAGE) II measurements,and the results indicate that for the zonal mean profiles,the SCIAMACHY retrievals show good agreement with SAGE II measurements,with the absolute differences being less than 2.3×10-5 km-1 from 14–25 km,and less than 5.9×10-6 km-1 from 25–35 km;and the relative differences being within 20% over the latitude range of 14–35 km.展开更多
The Greater Casablanca, like the other large cities, has experienced significant urban and industrial development in recent years, this development has certainly helped develop the productive fabric, generate signific...The Greater Casablanca, like the other large cities, has experienced significant urban and industrial development in recent years, this development has certainly helped develop the productive fabric, generate significant employment opportunities for hundreds of thousands of families, but at the expense of the mobility and quality of the environment particularly those of the air. The deterioration of the air quality affects more and more the population's health with significant cost and damage to the community, this study aims to quantify the degree of aerosols pollution damage and also its health effects.展开更多
Inhalation of 222Rn progeny in the domestic environment contributes the greatest fraction of the natural radiation exposure to the public. The ultrafine activity of these progeny amounts up to about l 0 percent of the...Inhalation of 222Rn progeny in the domestic environment contributes the greatest fraction of the natural radiation exposure to the public. The ultrafine activity of these progeny amounts up to about l 0 percent of the total activity (attached and ultrafine), but is considered to yield about 50 percent of the total radiation dose. Therefore, measurements of ultrafine fraction are essential for the estimation of radiation dose. The current study presents measured data on the total equilibrium equivalent concentration (EEC) and ultrafine equilibrium equivalent concentration (EECUn), ultrafine fraction (fb), attached and unattached activity size distributions of radon progeny in the low ventilated rooms at Minia University, Minia city, Egypt. A screen diffusion battery was used for collection the ultrafine fraction and measuring the total activity concentration of radon progeny. The attached activity size distribution of 214pb is determined by using a low pressure cascade impactor. The EEC of radon progeny varied between 1.3 and 18.9 Bq/m3 with a mean value of 5.2 ± 0.48 Bq/m2. The mean activity thermodynamic diameter (AMTD) ofultrafine of radon progeny was determined to be 1.26 nm with relative mean geometric standard deviations (GSD) of 1.3. The ultrafine fraction of radon progeny, fb, has a range 0.01 to 0.21 with an average of 0.08 ± 0.03. A relative mean GSD of 2.7 was determined for attached 2Lapb at a mean active median aerodynamic diameter (AMD) of 350 nm. Based on the above experimental results, the deposition fractions have been evaluated in each air way generation through the human lung by applying a lung deposition model. The bronchial deposition efficiencies of particles in the size range of attached radon progeny were found to be lower than those of ultrafine progeny. The effect of radon progeny deposition by adult male has been also studied for various levels of physical exertion. The dose conversion factor has been discussed as a function of fb.展开更多
The aerosol effect on clouds was explored using remote sensing of aerosol and cloud data at Shouxian, China. Non-precipitation, ice-free, and overcast clouds were firstly chosen by a combination of sky im- ages from t...The aerosol effect on clouds was explored using remote sensing of aerosol and cloud data at Shouxian, China. Non-precipitation, ice-free, and overcast clouds were firstly chosen by a combination of sky im- ages from the Total Sky Imager (TSI), cloud base heights from the Ceilometer, and vertical temperature profiles from the Balloon-Borne Sounding System (BBSS). Six cases were chosen in summer, and seven in autumn. The averaged cloud effective radii (re), cloud optical depth (COD), aerosol total light scattering coefficient (a), and liquid water path (LWP) are, respectivey, 6.47 μm, 35.4, 595.9 mm-1, 0.19 mm in summer, and 6.07 μm, 96.0, 471.7 mm-1, 0.37 mm in autumn. The correlation coefficient between re and tc was found to change from negative to positive value as LWP increases.展开更多
The contribution of anthropogenic mineral aerosol dust has been of interest to understand the impact of dust aerosols on climate, and the health of workers occupational exposure. Several studies have been investigated...The contribution of anthropogenic mineral aerosol dust has been of interest to understand the impact of dust aerosols on climate, and the health of workers occupational exposure. Several studies have been investigated the physical and chemical properties mainly in particulate matter. However, the characterizations have not extended diameters below to 1.0 μm. In this study, it described chemical composition and shape measurements of individual aerosol particles with 50% cut-off diameters less than 1.1 μm emitted at ceramic-tile manufacturing. Four emission sites of process were selected, and their samples were collected using a cascade-impactor, investigated using X-ray diffraction, energy dispersive X-ray spectroscopy, and digital image processing, where the data were analysed applying a combination of principal component and cluster analysis. Particles of tectosilicate (quartz, zeolite), phyllosilicate (illite, montmorillonite), and inosilicate (calcium silicate) were founded in all sampling sites; also, silicates mixed with transition metals oxides used as pigments (e.g., Fe, Ti, Co, Ni, Zn and Mo). Silicates were granulated and flat crystals with a transparent, translucent appearance; otherwise, the mixture had flake shapes and opaque appearance. Analyses of multivariate data showed that the process stages emissions were related with specific composition and shape suggesting the use three measurements related (1) the internal axis, (2) roundness and (3) roughness to isolate particles shapes, and the presence of transition metals oxides as emissions tracer of the ceramic industry.展开更多
Black carbon (BC) aerosol, accounting for a minor fraction of atmospheric aerosols, is attracting increased attentio1 due to its impact on air quality, human health, and climate change. Focusing on BC emission reduc...Black carbon (BC) aerosol, accounting for a minor fraction of atmospheric aerosols, is attracting increased attentio1 due to its impact on air quality, human health, and climate change. Focusing on BC emission reduction, this paper give1 a brief introduction to the sources and global distribution of BC. Along with the decrease of BC emissions from sue1 actions as the reduction of global greenhouse gases (GHGs) and regulating local air quality, it also highlights othet BC reduction approaches such as control and improvement of combustion conditions, the elimination of open biomas burning, and the sequestration of BC by biomass pyrolysis. Finally, it is stressed that at this moment there is no enougt reason to push BC reduction into any climate change related negotiations, although BC has been included in some o so-called win-win reduction targets for the quick response to both climate and non-climate appeals.展开更多
This paper presents an empirical model for estimating the zonal mean aerosol extinction profiles in the stratosphere over 10°-wide latitude bands between 60°S and 60°N, on the basis of Stratospheric Aer...This paper presents an empirical model for estimating the zonal mean aerosol extinction profiles in the stratosphere over 10°-wide latitude bands between 60°S and 60°N, on the basis of Stratospheric Aerosol and Gas Experiment(SAGE) II aerosol extinction measurements at 1.02, 0.525, and 0.452 μm during the volcanically quiescent period between 1998–2004. First, an empirical model is developed for calculating the stratospheric aerosol extinction profiles at 1.02 μm. Then, starting from the 1.02 μm extinction profile and an exponential spectral dependence, an empirical algorithm is developed that allows the aerosol extinction profiles at other wavelengths to be calculated. Comparisons of the model-calculated aerosol extinction profiles at the wavelengths of 1.02, 0.525, and 0.452 μm and the SAGE II measurements show that the model-calculated aerosol extinction coefficients conform well with the SAGE II values, with the relative differences generally being within 15% from 2 km above the tropopause to 40 km. The model-calculated stratospheric aerosol optical depths at the three wavelengths are also in good agreement with the corresponding optical depths derived from the SAGE II measurements, with the relative differences being within 0.9% for all latitude bands. This paper provides a useful tool in simulating zonal mean aerosol extinction profiles, which can be used as representative background stratospheric aerosols in view of atmospheric modeling and remote sensing retrievals.展开更多
In this study, a special method is proposed for detecting aerosols over land by analyzing satellitemeasured far IR radiation at three channels, 8.7, 11.5, and 12.5 lain. Sensitivity tests revealed that the behavioral ...In this study, a special method is proposed for detecting aerosols over land by analyzing satellitemeasured far IR radiation at three channels, 8.7, 11.5, and 12.5 lain. Sensitivity tests revealed that the behavioral features of radiative brightness temperatures (BTs) at these three channels with increasing optical depth are different among different types of aerosols. Analyzing how BTs and their differences, xBT (BT11.5-BT12.5) and YBT (BT8.7-BT11.5), behave with varying optical depth can help to qualitatively distinguish among aerosols and semi-quantitatively estimate their optical thicknesses. In addition, the authors found that the vertical density profile of aerosols has little impact on this method.展开更多
The air quality modeling system RAMS (Regional Atmospheric Modeling System)-CMAQ (Models-3 Community Multi-scale Air Quality) is developed to simulate the aerosol optical depth (AOD) and aerosol direct forcing (DF). T...The air quality modeling system RAMS (Regional Atmospheric Modeling System)-CMAQ (Models-3 Community Multi-scale Air Quality) is developed to simulate the aerosol optical depth (AOD) and aerosol direct forcing (DF). The aerosol-specific extinction, single scattering albedo, and asymmetry factor are parameterized based on Mie theory taking into account the aerosol size distribution, composition, refractive index, and water uptake of solution particles. A two-stream solar radiative model considers all gaseous molecular absorption, Rayleigh scattering, and aerosols and clouds. RAMSCMAQ is applied to simulate all major aerosol concentrations (e.g., sulfate, nitrate, ammonium, organic carbon, black carbon, fine soil, and sea salt) and AOD and DF over East Asia in 2005. To evaluate its performance, the simulated AOD values were compared with ground-based in situ measurements. The comparison shows that RAMSCMAQ performed well in most of the model domain and generally captured the observed variations. High AOD values (0.2 1.0) mainly appear in the Sichuan Basin as well as in central and southeastern China. The geographic distribution of DF generally follows the AOD distribution patterns, and the DF at the top-of-the-atmosphere is less than 25 and 20 W m 2 in clear-sky and all-sky over the Sichuan Basin. Both AOD and DF exhibit seasonal variations with lower values in July and higher ones in January The DF could obviously be impacted by high cloud fractions.展开更多
Low winter temperature is generally recognized as the chief factor limiting the northward distribution of Osmanthus fragrans. O. fragrans has been cultivated in Kaifeng for nearly two decades, yet little is known rega...Low winter temperature is generally recognized as the chief factor limiting the northward distribution of Osmanthus fragrans. O. fragrans has been cultivated in Kaifeng for nearly two decades, yet little is known regarding how well this plant has adapted to the city's cold winter. In a city-wide survey, we periodically examined O. fragrans leaves for visible symptoms of freeze damage, then measured leaf soluble sugar content, leaf electric conductivity, palisade layer thickness/leaf thickness ratio, and spongy layer thickness/leaf thickness ratio of several cultivars. The data thus collected were assessed to determine the cultivars' cold resistance levels. Our results indicate that the northward distribution of O. fragrans may be limited primarily by low spring temperatures rather than low winter temperatures. O. fragrans Sijigui and Huangchuan Jingui are the most cold resistant O. fragrans cultivars in Kaifeng, China.展开更多
This paper describes the determination of water content of water-soluble paints by gas chromatography. The water in paints is extracted by dimethyl formamide (DMF) as a solvent.Isopropanol is used as an internal stand...This paper describes the determination of water content of water-soluble paints by gas chromatography. The water in paints is extracted by dimethyl formamide (DMF) as a solvent.Isopropanol is used as an internal standard. The mixture is separated by low-speed centrifugation.Then a 1-uL sample of the supernatant from the prepared solution is injected into the gas chromatograph. The water content is determined by internal standard calibration curve. The rate of recovery of added standard of this method is more than 98%. Relative mean deviation is less than 3‰.The linearity of calibration curve is good and relativity coefficient is higher than 0.998.展开更多
Hydrogen sulfide in rural biogas was removed with liquid-phase catalytic oxidation.By using rare earth as catalyst,and sulfosalicylic acid as stabilizer,H2S purification efficiency could increase as high as 96%,and su...Hydrogen sulfide in rural biogas was removed with liquid-phase catalytic oxidation.By using rare earth as catalyst,and sulfosalicylic acid as stabilizer,H2S purification efficiency could increase as high as 96%,and sulfur capacity of the composite solution was about 3 g/L.The results show that purification efficiency was affected by catalyst addition,pH,experimental temperature,and sulfur capacity.The parameters effects on catalytic oxidation were studied,and the optimized conditions were that Fe3+ concentration 0.08 mg/L,reaction temperature 70°C,pH 9.0,with a absorption solution volume of 50 mL,a gas flow rate 200 mL/min,and H2S mass concentration of 1.58-2.02 mg/m3.展开更多
Multiple sulfur isotopes (32S, 335, 345, 365) and oxygen isotopes (160, 180) in Beijing aerosols were measured with MAT-253 isotope mass spectrometer. The δ345 values of Beijing aerosol samples range from 1.68%o ...Multiple sulfur isotopes (32S, 335, 345, 365) and oxygen isotopes (160, 180) in Beijing aerosols were measured with MAT-253 isotope mass spectrometer. The δ345 values of Beijing aerosol samples range from 1.68%o to 12.57%o with an average value of 5.86%0, indicating that the major sulfur source is from direct emission during coal combustion. The c5180 values vary from -5.29%0 to 9.02%0 with an average value of 5.17%o, revealing that the sulfate in Beijing aerosols is mainly composed of the secondary sulfate. The main heterogeneous oxidation of SO2 in atmosphere is related to H202 in July and August, whereas H202 oxidation and Fe3+ catalytic oxidation with SO2 exist simultaneously in September and October. Remarkable sulfur iso- tope mass-independent fractionation effect is found in Beijing aerosols, which is commonly attributed to the photochemical oxidation of SO2 in the stratosphere. In addition, thermochemical reactions of sulfur-bearing compounds might be also a source of sulfur isotope anomalies based on the correlation between A335 and CAPE.展开更多
基金funded by the National BasicResearch Program of China (Grant No. 2006CB403702)the Public Meteorology Special Foundation of Ministry of Science and Technology (Grant No. GYHY200706036)the National Natural Science Foundation of China (Grant No. 60638020)
文摘The total dust column and the dry deposition flux were calculated based on the optical properties that were measured by a shipboard sun photometer POM-01 MK II in a cloud-free and nonfrontal dust condition on 24 April 2006. The total dust column was calculated by using an integration method of the particle size distribution; the mean value was 1.42±0.30 g m 2. A linear correlation between the total dust column and the aerosol optical depth (AOD) with a linear factor of 2.7 g m 2 over the Sahara was applied to calculate the total dust column in this study; the results were lower than these calculated by the integration method. A reasonable factor of 3.2 g m^-2 was achieved by minimizing the standard deviation (SD) of the two methods. The two layers model, which includes the deposition processes of turbulent transfer, Brownian diffusion, impaction and gravitational settling over the sea's surface, was used to calculate the dry deposition flux; the mean value was 5.05±2.49 μg m^-2 s^-1. A correlation among the total dust column, dry deposition flux, AOD, and effective radius was discussed. The correlation between the total better than that between dust column and the AOD was the total dust column and the effective radius; however, the correlation between the dry deposition flux and the effective radius was better than that between the dry deposition flux and the AOD.
基金supported by the National Basic Research Program of China[grant number 2014CB953802]the "Strategic Priority Research Program(B)" of the Chinese Academy of Sciences[grant numbers XDB05030105,XDB05030102,and XDB05030103]
文摘The regional air quality modeling system Regional Atmospheric Modeling System–Community Multiscale Air Quality was applied to estimate the spatial distribution and seasonal variation in nitrogen wet deposition over East Asia in 2010. The simulated results were evaluated by comparing modeled precipitation rates and ion concentrations, such as ammonium(NH_4~+), nitrate(NO_3^-), and sulfate, in rainwater, against observations obtained from Acid Deposition Monitoring Network in East Asia and meteorological stations in China. Comparison of simulated and observed precipitation showed that the modeling system can reproduce seasonal precipitation patterns reasonably well. For major ion species, the simulated results in most cases were in good agreement with those observed. Analysis of the modeled wet deposition distributions indicated that China experiences noticeable variation in wet deposition patterns throughout the year. Nitrogen wet deposition(NH_4~+ + NO_3^-) during summer and spring accounted for 71% of the annual total(3.9 Tg N yr^(-1)), including 42.7% in summer. Precipitation plays a larger role in the seasonal variation of wet deposition; whereas, aerosol concentrations affect its distribution patterns. In China, the amount of annual nitrogen wet deposition ranged from 1 to 18 kg N ha^(-1). Nitrogen in wet deposition was mainly in the form of NH_4~+, accounting for 65.76% of the total amount, and the molar ratio of NH_4~+∕NO_3^- was mostly more than 1, indicating a relatively larger effect from agricultural activities.
基金funded by the National Natural Science Foundation of China (Grant No.41275047)the National Basic Research Program of China (Grant No.2013CB955801)the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No.XDA05100300)
文摘Stratospheric aerosol extinction profiles are retrieved from Scanning Imaging Absorption Spectrometer for Atmospheric Cartography(SCIAMACHY) limb scatter measurements.In the process of retrieval,the SCIATRAN radiative transfer model is used to simulate the limb scattering radiation received by the SCIAMACHY instrument,and an optimal estimation algorithm is used to calculate the aerosol extinction profiles.Sensitivity analyses are performed to investigate the impact of the surface albedo on the accuracy of the retrieved aerosol extinction profiles in the northern midlatitudes.It is found that the errors resulting from the bias of the assumed surface albedo in the retrieval are generally below 6%.The retrieved SCIAMACHY aerosol extinction profiles are compared with corresponding Stratospheric Aerosol and Gas Experiment(SAGE) II measurements,and the results indicate that for the zonal mean profiles,the SCIAMACHY retrievals show good agreement with SAGE II measurements,with the absolute differences being less than 2.3×10-5 km-1 from 14–25 km,and less than 5.9×10-6 km-1 from 25–35 km;and the relative differences being within 20% over the latitude range of 14–35 km.
文摘The Greater Casablanca, like the other large cities, has experienced significant urban and industrial development in recent years, this development has certainly helped develop the productive fabric, generate significant employment opportunities for hundreds of thousands of families, but at the expense of the mobility and quality of the environment particularly those of the air. The deterioration of the air quality affects more and more the population's health with significant cost and damage to the community, this study aims to quantify the degree of aerosols pollution damage and also its health effects.
文摘Inhalation of 222Rn progeny in the domestic environment contributes the greatest fraction of the natural radiation exposure to the public. The ultrafine activity of these progeny amounts up to about l 0 percent of the total activity (attached and ultrafine), but is considered to yield about 50 percent of the total radiation dose. Therefore, measurements of ultrafine fraction are essential for the estimation of radiation dose. The current study presents measured data on the total equilibrium equivalent concentration (EEC) and ultrafine equilibrium equivalent concentration (EECUn), ultrafine fraction (fb), attached and unattached activity size distributions of radon progeny in the low ventilated rooms at Minia University, Minia city, Egypt. A screen diffusion battery was used for collection the ultrafine fraction and measuring the total activity concentration of radon progeny. The attached activity size distribution of 214pb is determined by using a low pressure cascade impactor. The EEC of radon progeny varied between 1.3 and 18.9 Bq/m3 with a mean value of 5.2 ± 0.48 Bq/m2. The mean activity thermodynamic diameter (AMTD) ofultrafine of radon progeny was determined to be 1.26 nm with relative mean geometric standard deviations (GSD) of 1.3. The ultrafine fraction of radon progeny, fb, has a range 0.01 to 0.21 with an average of 0.08 ± 0.03. A relative mean GSD of 2.7 was determined for attached 2Lapb at a mean active median aerodynamic diameter (AMD) of 350 nm. Based on the above experimental results, the deposition fractions have been evaluated in each air way generation through the human lung by applying a lung deposition model. The bronchial deposition efficiencies of particles in the size range of attached radon progeny were found to be lower than those of ultrafine progeny. The effect of radon progeny deposition by adult male has been also studied for various levels of physical exertion. The dose conversion factor has been discussed as a function of fb.
基金supported by the Knowledge Innovation Program of the Chinese Academy of Sciences(KZCX2-YW-QN201)the National Basic Research Program of China(973 Program)(2006CB403706 and 2010CB950804)the National Natural Science Foundation of China(40775009 and 40875084)
文摘The aerosol effect on clouds was explored using remote sensing of aerosol and cloud data at Shouxian, China. Non-precipitation, ice-free, and overcast clouds were firstly chosen by a combination of sky im- ages from the Total Sky Imager (TSI), cloud base heights from the Ceilometer, and vertical temperature profiles from the Balloon-Borne Sounding System (BBSS). Six cases were chosen in summer, and seven in autumn. The averaged cloud effective radii (re), cloud optical depth (COD), aerosol total light scattering coefficient (a), and liquid water path (LWP) are, respectivey, 6.47 μm, 35.4, 595.9 mm-1, 0.19 mm in summer, and 6.07 μm, 96.0, 471.7 mm-1, 0.37 mm in autumn. The correlation coefficient between re and tc was found to change from negative to positive value as LWP increases.
文摘The contribution of anthropogenic mineral aerosol dust has been of interest to understand the impact of dust aerosols on climate, and the health of workers occupational exposure. Several studies have been investigated the physical and chemical properties mainly in particulate matter. However, the characterizations have not extended diameters below to 1.0 μm. In this study, it described chemical composition and shape measurements of individual aerosol particles with 50% cut-off diameters less than 1.1 μm emitted at ceramic-tile manufacturing. Four emission sites of process were selected, and their samples were collected using a cascade-impactor, investigated using X-ray diffraction, energy dispersive X-ray spectroscopy, and digital image processing, where the data were analysed applying a combination of principal component and cluster analysis. Particles of tectosilicate (quartz, zeolite), phyllosilicate (illite, montmorillonite), and inosilicate (calcium silicate) were founded in all sampling sites; also, silicates mixed with transition metals oxides used as pigments (e.g., Fe, Ti, Co, Ni, Zn and Mo). Silicates were granulated and flat crystals with a transparent, translucent appearance; otherwise, the mixture had flake shapes and opaque appearance. Analyses of multivariate data showed that the process stages emissions were related with specific composition and shape suggesting the use three measurements related (1) the internal axis, (2) roundness and (3) roughness to isolate particles shapes, and the presence of transition metals oxides as emissions tracer of the ceramic industry.
基金co-supported by China 973 project of MOST(2011CB403401)China Postdoctoral Science Foundation(20080440463,200902157)
文摘Black carbon (BC) aerosol, accounting for a minor fraction of atmospheric aerosols, is attracting increased attentio1 due to its impact on air quality, human health, and climate change. Focusing on BC emission reduction, this paper give1 a brief introduction to the sources and global distribution of BC. Along with the decrease of BC emissions from sue1 actions as the reduction of global greenhouse gases (GHGs) and regulating local air quality, it also highlights othet BC reduction approaches such as control and improvement of combustion conditions, the elimination of open biomas burning, and the sequestration of BC by biomass pyrolysis. Finally, it is stressed that at this moment there is no enougt reason to push BC reduction into any climate change related negotiations, although BC has been included in some o so-called win-win reduction targets for the quick response to both climate and non-climate appeals.
基金supported by the National Natural Science Foundation of China (Grant No. 41275047)the National Basic Research Program of China (Grant No. 2013CB955801)the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDA05100300)
文摘This paper presents an empirical model for estimating the zonal mean aerosol extinction profiles in the stratosphere over 10°-wide latitude bands between 60°S and 60°N, on the basis of Stratospheric Aerosol and Gas Experiment(SAGE) II aerosol extinction measurements at 1.02, 0.525, and 0.452 μm during the volcanically quiescent period between 1998–2004. First, an empirical model is developed for calculating the stratospheric aerosol extinction profiles at 1.02 μm. Then, starting from the 1.02 μm extinction profile and an exponential spectral dependence, an empirical algorithm is developed that allows the aerosol extinction profiles at other wavelengths to be calculated. Comparisons of the model-calculated aerosol extinction profiles at the wavelengths of 1.02, 0.525, and 0.452 μm and the SAGE II measurements show that the model-calculated aerosol extinction coefficients conform well with the SAGE II values, with the relative differences generally being within 15% from 2 km above the tropopause to 40 km. The model-calculated stratospheric aerosol optical depths at the three wavelengths are also in good agreement with the corresponding optical depths derived from the SAGE II measurements, with the relative differences being within 0.9% for all latitude bands. This paper provides a useful tool in simulating zonal mean aerosol extinction profiles, which can be used as representative background stratospheric aerosols in view of atmospheric modeling and remote sensing retrievals.
基金supported by the National Basic Research Program of China (Grant No. 2006CB403705)
文摘In this study, a special method is proposed for detecting aerosols over land by analyzing satellitemeasured far IR radiation at three channels, 8.7, 11.5, and 12.5 lain. Sensitivity tests revealed that the behavioral features of radiative brightness temperatures (BTs) at these three channels with increasing optical depth are different among different types of aerosols. Analyzing how BTs and their differences, xBT (BT11.5-BT12.5) and YBT (BT8.7-BT11.5), behave with varying optical depth can help to qualitatively distinguish among aerosols and semi-quantitatively estimate their optical thicknesses. In addition, the authors found that the vertical density profile of aerosols has little impact on this method.
基金supported by the Knowledge Innovation Program of the Chinese Academy of Sciences (KZCX2-YW-Q11-04)the National Basic research Program of China (2006CB403702 and 2007CB407303)
文摘The air quality modeling system RAMS (Regional Atmospheric Modeling System)-CMAQ (Models-3 Community Multi-scale Air Quality) is developed to simulate the aerosol optical depth (AOD) and aerosol direct forcing (DF). The aerosol-specific extinction, single scattering albedo, and asymmetry factor are parameterized based on Mie theory taking into account the aerosol size distribution, composition, refractive index, and water uptake of solution particles. A two-stream solar radiative model considers all gaseous molecular absorption, Rayleigh scattering, and aerosols and clouds. RAMSCMAQ is applied to simulate all major aerosol concentrations (e.g., sulfate, nitrate, ammonium, organic carbon, black carbon, fine soil, and sea salt) and AOD and DF over East Asia in 2005. To evaluate its performance, the simulated AOD values were compared with ground-based in situ measurements. The comparison shows that RAMSCMAQ performed well in most of the model domain and generally captured the observed variations. High AOD values (0.2 1.0) mainly appear in the Sichuan Basin as well as in central and southeastern China. The geographic distribution of DF generally follows the AOD distribution patterns, and the DF at the top-of-the-atmosphere is less than 25 and 20 W m 2 in clear-sky and all-sky over the Sichuan Basin. Both AOD and DF exhibit seasonal variations with lower values in July and higher ones in January The DF could obviously be impacted by high cloud fractions.
基金This research was supported by The National Natural Science Foundation of China (Grant No. 30970176) and The Innovation Scientists and Technicians Troop Construction Projects of Henan Province (Grant No. 094100510018). The authors thanked Yuanji Han, Xueyan Yan, Wangjun Yuan, and Meifang Dong for their assistance.
文摘Low winter temperature is generally recognized as the chief factor limiting the northward distribution of Osmanthus fragrans. O. fragrans has been cultivated in Kaifeng for nearly two decades, yet little is known regarding how well this plant has adapted to the city's cold winter. In a city-wide survey, we periodically examined O. fragrans leaves for visible symptoms of freeze damage, then measured leaf soluble sugar content, leaf electric conductivity, palisade layer thickness/leaf thickness ratio, and spongy layer thickness/leaf thickness ratio of several cultivars. The data thus collected were assessed to determine the cultivars' cold resistance levels. Our results indicate that the northward distribution of O. fragrans may be limited primarily by low spring temperatures rather than low winter temperatures. O. fragrans Sijigui and Huangchuan Jingui are the most cold resistant O. fragrans cultivars in Kaifeng, China.
文摘This paper describes the determination of water content of water-soluble paints by gas chromatography. The water in paints is extracted by dimethyl formamide (DMF) as a solvent.Isopropanol is used as an internal standard. The mixture is separated by low-speed centrifugation.Then a 1-uL sample of the supernatant from the prepared solution is injected into the gas chromatograph. The water content is determined by internal standard calibration curve. The rate of recovery of added standard of this method is more than 98%. Relative mean deviation is less than 3‰.The linearity of calibration curve is good and relativity coefficient is higher than 0.998.
基金Project(2008ZX07105-002) supported by the Erhai Lake Project of National Science and Technology Major Project in the 11th Five years Plan of China
文摘Hydrogen sulfide in rural biogas was removed with liquid-phase catalytic oxidation.By using rare earth as catalyst,and sulfosalicylic acid as stabilizer,H2S purification efficiency could increase as high as 96%,and sulfur capacity of the composite solution was about 3 g/L.The results show that purification efficiency was affected by catalyst addition,pH,experimental temperature,and sulfur capacity.The parameters effects on catalytic oxidation were studied,and the optimized conditions were that Fe3+ concentration 0.08 mg/L,reaction temperature 70°C,pH 9.0,with a absorption solution volume of 50 mL,a gas flow rate 200 mL/min,and H2S mass concentration of 1.58-2.02 mg/m3.
基金supported by National Natural Science Foundation of China(Grant Nos.41240025 and 41373023)Start-up Foundation of the Ministry of Education for Overseas Returnees(Grant No.2012s001)Prospective Researching Project of Industry-University-Research of Jiangsu Province(Grant No.BY2013007-03)
文摘Multiple sulfur isotopes (32S, 335, 345, 365) and oxygen isotopes (160, 180) in Beijing aerosols were measured with MAT-253 isotope mass spectrometer. The δ345 values of Beijing aerosol samples range from 1.68%o to 12.57%o with an average value of 5.86%0, indicating that the major sulfur source is from direct emission during coal combustion. The c5180 values vary from -5.29%0 to 9.02%0 with an average value of 5.17%o, revealing that the sulfate in Beijing aerosols is mainly composed of the secondary sulfate. The main heterogeneous oxidation of SO2 in atmosphere is related to H202 in July and August, whereas H202 oxidation and Fe3+ catalytic oxidation with SO2 exist simultaneously in September and October. Remarkable sulfur iso- tope mass-independent fractionation effect is found in Beijing aerosols, which is commonly attributed to the photochemical oxidation of SO2 in the stratosphere. In addition, thermochemical reactions of sulfur-bearing compounds might be also a source of sulfur isotope anomalies based on the correlation between A335 and CAPE.