Coal combustion in the domestic stoves, which is common in most parts of the Chinese countryside, can release harmful substances into the air and cause health issues. In this study, particles emitted from laboratory s...Coal combustion in the domestic stoves, which is common in most parts of the Chinese countryside, can release harmful substances into the air and cause health issues. In this study, particles emitted from laboratory stove combustion of the raw powder coals were analyzed for morphologies and chemical compositions by using transmission electron microscopy （TEM） coupled with energy-dispersive X-ray spectrometry （EDX）. The coal burning-derived individual particles were classified into two groups： carbonaceous particles （including soot aggregates and organic particles） and non-carbonaceous particles （including sulfate, mineral and metal particles）. The non-carbonaceous particles, which constituted a majority of the coal burning-derived emissions, were subdivided into Si-rich, S-rich, K-rich, Ca-rich, and Fe-rich particles according to the elemental compositions. The Si-rich, S-rich and K-rich particles are commonly observed in the coal burning emission. The proportions for particles of different types exhibit obvious coal-issue dependence. Burning of coal with high ash yield could emit more non-carbonaceous particles, and burning of coal with high sulfur content can emit more S-rich particles. By comparing the S-rich particles from this coal burning experiment with those in the atmosphere, we draw a conclusion that some S-rich particles in the atmosphere in China could be mainly sourced from coal combustion.展开更多
Aerosol samples were collected in summer in Macao, a coastal city of the Pearl River Delta Region in China. Morphology, size, elemental composition, and mixing state of individual aerosol particles were determined by ...Aerosol samples were collected in summer in Macao, a coastal city of the Pearl River Delta Region in China. Morphology, size, elemental composition, and mixing state of individual aerosol particles were determined by scanning electron microscopy coupled energy dispersive X-ray （SEM/EDX） and transmission electron microscopy （TEM）. Based on the morphologies of 5711 aerosol particles, they consist of soot （32%）, mineral （17%）, secondary-（22%）, and unknown fine particles （29%）. The sizes of these particles were mostly distributed between 0.1 and 0.4 μm. Compositions of 202 mineral particles were obtained by SEM/EDX. Mineral particles were mainly classified into three types： Si-rich, Ca-rich, and Na-rich. The compositions of typical mineral particles can indicate their sources in sampling location. For example, mineral particles, collected along the main street, were associated with trace amounts of heavy metals, such as Zn, Ti, Mn, Ba, Pb, and As. TEM observations indicate that most Na-rich particles were aged sea salt particles （e.g., Na2SO4 and NaNO3） which formed through heterogeneous chemical reactions between sea salt and acidic gases. Additionally, aging time of soot was short in Macao due to high humidity, high temperature, and high levels of sunlight in Macao. Most of soot and fine mineral dust particles were internally mixed with secondary particles.展开更多
Nitrogen-containing organic compounds(NOCs)may potentially contribute to aqueous secondary organic aerosols,yet the different formation of NOCs in aerosol particles and cloud droplets remains unclear.With the in-situ ...Nitrogen-containing organic compounds(NOCs)may potentially contribute to aqueous secondary organic aerosols,yet the different formation of NOCs in aerosol particles and cloud droplets remains unclear.With the in-situ measurements performed at a mountain site(1690 m a.s.l.)in southern China,we investigated the formation of NOCs in the cloud droplets and the cloud-free particles,based on their mixing state information of NOCscontaining particles by single particle mass spectrometry.The relative abundance of NOCs in the cloud-free particles was significantly higher than those in cloud residual(cloud RES)particles.NOCs were highly correlated with carbonyl compounds(including glyoxalate and methylglyoxal)in the cloud-free particles,however,limited correlation was observed for cloud RES particles.Analysis of their mixing state and temporal variations highlights that NOCs was mainly formed from the carbonyl compounds and ammonium in the cloud-free particles,rather than in the cloud RES particles.The results support that the formation of NOCs from carbonyl compounds is facilitated in concentrated solutions in wet aerosols,rather than cloud droplets.In addition,we have identified the transport of biomass burning particles that facilitate the formation of NOCs,and that the observed NOCs is most likely contributed to the light absorption.These findings have implications for the evaluation of NOCs formation and their contribution to light absorption.展开更多
The nondestructive characterization of the mixing state of individual fine particles using the traditional single particle analysis technique remains a challenge.In this study,fine particles were collected during haze...The nondestructive characterization of the mixing state of individual fine particles using the traditional single particle analysis technique remains a challenge.In this study,fine particles were collected during haze events under different pollution levels from September 5 to 112017 in Beijing,China.A nondestructive surface-enhanced Raman scattering(SERS)technique was employed to investigate the morphology,chemical composition,and mixing state of the multiple components in the individual fine particles.Optical image and SERS spectral analysis results show that soot existing in the form of opaque material was predominant during clear periods(PM_(2.5)≤75μg/m^(3)).During polluted periods(PM_(2.5)>75μg/m^(3)),opaque particles mixed with transparent particles(nitrates and sulfates)were generally observed.Direct classical least squares analysis further identified the relative abundances of the three major components of the single particles:soot(69.18%),nitrates(28.71%),and sulfates(2.11%).A negative correlation was observed between the abundance of soot and the mass concentration of PM_(2.5).Furthermore,mapping analysis revealed that on hazy days,PM_(2.5)existed as a core-shell structure with soot surrounded by nitrates and sulfates.This mixing state analysis method for individual PM_(2.5)particles provides information regarding chemical composition and haze formation mechanisms,and has the potential to facilitate the formulation of haze prevention and control policies.展开更多
Thin film methods and X ray energy dispersive technique were applied to analyze sulfate-containing particles inBeijing in order to examine their features and sources. Atmospheric aerosol particles were collected on el...Thin film methods and X ray energy dispersive technique were applied to analyze sulfate-containing particles inBeijing in order to examine their features and sources. Atmospheric aerosol particles were collected on electron microscope meshes according to two size ranges: coarse particles (r>0.5μm) and fine particles (0.5μm>r>0. 1μm) by using a two-stage impactor. It was found that more than seventy percent of the fine particles and about twenty percentof the coarse particles were sulfate-containing particles. These particles were formed mainly through heterogeneousnucleation. The element composition analyses revealed that the atmospheric aerosol particles in Beijing were domi-nated by crustal particles and construction dust.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
An intense Asian dust storm invadedQinhuangdao,a coastal city ofNorth China on April 11-14,2023.We analyzed the bulk water-soluble inorganic ions(WSII)of PM_(10)and PM_(2.5)using an Ion Chromatograph and investigated ...An intense Asian dust storm invadedQinhuangdao,a coastal city ofNorth China on April 11-14,2023.We analyzed the bulk water-soluble inorganic ions(WSII)of PM_(10)and PM_(2.5)using an Ion Chromatograph and investigated individual particlemorphology and elemental composition using a scanning electron microscope coupled with energy dispersive X-ray.The results showed when the dust was directly transported to the sampling site from northwestern China(direct transport stages),the PM_(10)mass concentrations were high(675.0μg/m^(3))but the relative humidity(RH)was low.Total WSII were 19.54μg/m^(3)and 11.17μg/m^(3),accounting for 2.90%and 7.25%of the PM_(10)and PM_(2.5),respectively.In addition,the proportion of S-containing individual mineral dust was low(28.7%-35.3%).The results suggested there were limited secondary inorganic aerosol formation.However,when the dust was transported back to the sampling site across the Bohai Sea in the following days(reverse transport stages),both the PM_(10)mass concentrations(462.3μg/m^(3))and RH were high.Total WSII were 43.75μg/m^(3)and 18.71μg/m^(3),accounting for 9.62%and 14.45%of the total PM_(10)and PM_(2.5),respectively.The proportion of S-containing particles was 51.5%-72.5%.In addition,the concentration of NO_(3)^(−)was much higher than that of SO_(4)^(2−).The results suggested both the sulfate and nitrate formation occurred on coarse mineral dust but the nitrate formation exceeded sulfate formation.Interestingly,mostmineral dust,including Sirich particles contained Cl when they passed through the marine atmosphere.The results highlighted the heterogeneous reactions of dust varied in different transport stages.展开更多
To understand the composition and major sources of aerosol particles in Lhasa City on the Tibetan Plateau （TP）, individual particles were collected from 2 February to 8 March, 2013 in Tibet University. The mean conc...To understand the composition and major sources of aerosol particles in Lhasa City on the Tibetan Plateau （TP）, individual particles were collected from 2 February to 8 March, 2013 in Tibet University. The mean concentrations of both PM2.5 and PM10 during the sampling were 25.7 ± 21.7 and 57.2 ± 46.7 μg/m^3, respectively, much lower than those of other cities in East and South Asia, but higher than those in the remote region in TP like Nam Co, indicating minor urban pollution. Combining the observations with the meteorological parameters and back trajectory analysis, it was concluded that local sources controlled the pollution during the sampling. Transmission electron microscopy （TEM） combined with energydispersive X-ray spectra （EDS） was used to study 408 particles sampled on four days. Based on the EDS analysis, a total of 8 different particle categories were classified for all 408 particles, including Si-rich, Ca-rich, soot, K-rich, Fe-rich, Pb-rich, Al-rich and other particles. The dominant elements were Si, A1 and Ca, which were mainly attributed to mineral dust in the earth＇s crust such as feldspar and clay. Fe-, Pb-, K-, Al-rich particles and soot mainly originated from anthropogenic sources like firework combustion and biomass burning during the sampling. During the sampling, the pollution mainly came from mineral dust, while the celebration ceremony and religious ritual produced a large quantity of anthro- pogenic metal-bearing particles on 9 and 25 February 2013. Cement particles also had a minor influence. The data obtained in this study can be useful for developing pollution control strategies.展开更多
In recent decades, coastal ports have experienced rapid development and become an important economic and ecological hub in China. Atmospheric particle is a research hotspot in atmospheric environmental sciences in inl...In recent decades, coastal ports have experienced rapid development and become an important economic and ecological hub in China. Atmospheric particle is a research hotspot in atmospheric environmental sciences in inland regions. However, few studies on the atmospheric particle were conducted in coastal port areas in China, which indeed suffers atmospheric particle pollution. Lack of the physicochemical characteristics of fine particles serves as an obstacle toward the accurate control for air pollution in the coastal port area in China. Here, a field observation was conducted in an important coastal port city in Yangtze River Delta from March 6 to March 19, 2019. The average PM2.5 concentration was 63.7 ±27.8 μg/m^3 and NO3^-, SO4^2-, NH4^+, and organic matter accounted for ?60% of PM 2.5. Fe was the most abundant trace metal element and V as the ship emission indicator was detected. Transmission electron microscopy images showed that SK-rich, soot, Fe, SK-soot and SK-Fe were the major individual particles in the coastal port. V and soluble Fe were detected in sulfate coating of SK-Fe particles. We found that anthropogenic emissions, marine sea salt, and secondary atmosphere process were the major sources of fine particles. Backward trajectory analysis indicated that the dominant air masses were marine air mass, inland air mass from northern Zhejiang and inland-marine mixed air mass from Shandong and Shanghai during the sampling period. The findings can help us better understand the physicochemical properties of atmospheric fine particles in the coastal port of Eastern China.展开更多
Heterogeneous reactions on the aerosol particle surface in the atmosphere play important roles in air pollution, climate change, and global biogeochemical cycles. However, the reported uptake coefficients of heterogen...Heterogeneous reactions on the aerosol particle surface in the atmosphere play important roles in air pollution, climate change, and global biogeochemical cycles. However, the reported uptake coefficients of heterogeneous reactions usually have large variations and may not be relevant to real atmospheric conditions. One of the major reasons for this is the use of bulk samples in laboratory experiments, while particles in the atmosphere are suspended individually. A number of technologies have been developed recently to study heterogeneous reactions on the surfaces of individual particles. Precise measurements on the reactive surface area, volume, and morphology of individual particles are necessary for calculating the uptake coefficient, quantifying reactants and products, and understanding the reaction mechanism better. In this study, for the first time we used synchrotron radiation X-ray computed tomography（XCT） and micro-Raman spectrometry to measure individual CaCO_3 particle morphology, with sizes ranging from 3.5–6.5 μm. Particle surface area and volume were calculated using a reconstruction method based on software threedimensional（3-D） rendering. The XCT was first validated with high-resolution fieldemission scanning electron microscopy（FE-SEM） to acquire accurate CaCO_3 particle surface area and volume estimates. Our results showed an average difference of only 6.1% in surface area and 3.2% in volume measured either by micro-Raman spectrometry or X-ray tomography. X-ray tomography and FE-SEM can provide more morphological details of individual Ca CO3 particles than micro-Raman spectrometry. This study demonstrated that X-ray computed tomography and micro-Raman spectrometry can precisely measure the surface area, volume, and morphology of an individual particle.展开更多
Atmospheric metal pollution is a significant environmental issue in China.Understanding the microscopic characteristics of metallic elements are crucial for investigating their sources and health effects,but this info...Atmospheric metal pollution is a significant environmental issue in China.Understanding the microscopic characteristics of metallic elements are crucial for investigating their sources and health effects,but this information is still limited.In this study,transmission electron microscopy(TEM)combined with bulk analysis method were employed to investigate the microscopic characteristics and mass concentrations of atmospheric metallic elements at a village site and an urban site located in North China Plain during wintertime.Our results reveal that the total mass concentrations of 16 metallic elements(including nine toxic heavy metallic elements)in PM_(2.5)were 3439.18±1101.24 ng/m^(3)(1129.6±376.85 ng/m^(3))at the village site and 3555.1±916.71 ng/m^(3)(1295.26±446.39 ng/m^(3))at urban site,accounting for 2.23%and 2.76%of PM_(2.5),respectively.We found that K,Ca,and Fe were the dominant elements,constituting over 75%of total metal mass.TEM analysis indicates that these metallic elements were mainly enriched in six types of individual particles,including K-rich,mineral,fly ash,Fe-rich,Zn-rich,and Pb-rich particles.Mineral particles were predominant in all individual metal particles at urban site,while K-rich particles became the dominant metal particles influenced by residential biomass burning at village site.Moreover,we found toxic metal particles(Fe-rich,Zn-rich,Pb-rich,and fly ash)presented smaller mean sizes(243 nm)in village air compared to urban air(337 nm),suggesting that metal particles in village air might pose a higher health risk to the residents.These results emphasize that atmospheric metal pollution in the village areas need more attentions in the future.展开更多
Investigating the heterogeneous reaction on individual atmospheric particles is important because it approximates actual atmospheric conditions and can aid in reducing artifacts in elucidating real mechanisms and proc...Investigating the heterogeneous reaction on individual atmospheric particles is important because it approximates actual atmospheric conditions and can aid in reducing artifacts in elucidating real mechanisms and processes,and determining real kinetic parameters of the atmosphere relevance.This study developed a Raman microspectrometry method to investigate heterogeneous reactions on individual particles.The method was applied to the reaction of NO2 with individual CaCO3 particles.It was demonstrated that Raman microspectrometry can obtain information on both chemical composition and microscopic morphology at the same time,as well as information on chemical characteristics,such as the phase,which is useful for studying reaction processes.Raman spectra of individual particles deposited on a substrate showed no interference by morphological resonance,which is helpful for obtaining high-quality spectra.Moreover,Raman microspectrometry was compared with other methods for investigating heterogeneous reactions on individual particles and was found to have several advantageous characteristics.展开更多
Recent observations of Asian dust storms show an eastern expansion of the source area to degraded lands, where dust emissions have been little studied. The dust concentrations over the saline land of the western Songn...Recent observations of Asian dust storms show an eastern expansion of the source area to degraded lands, where dust emissions have been little studied. The dust concentrations over the saline land of the western Songnen Plain （SSL）, Northeastern China, are circumstantially higher than those from the northwestern Chinese deserts. These concentrations are sensitive to the surface soil conditions and wind velocity on the ground. The dust samples collected during dust storm events on the SSL contain abundant Na, Mg, A1, K, Ca, Fe and Ti, as well as toxic elements such as Cu, V, Zn and Ba. Individual particle analysis reveals that fine saline particles （〈 10 μm in diameter） on the saline land, consisting largely of carbonate, halite and sulfate together with lithogenic minerals such as SiO2 and aluminosilicate, are eventually uplifted during the interval from spring to autuum. The predominantly fine saline particles uplifted from the SSL are likely transported eastward by the winter monsoon circulation and westerlies. Recent degradation of saline lands in Northeastern China would not only increase the frequency of dust storm events in the downwind area, but also might change the chemical composition of the Asian dust emissions.展开更多
In an urban-transit bus, fueled by biodiesel in Toledo, Ohio, single inhalable particle samples in October 2008 were collected and detected by scanning electron microscopy and energy dispersive X-ray spectrometry （SE...In an urban-transit bus, fueled by biodiesel in Toledo, Ohio, single inhalable particle samples in October 2008 were collected and detected by scanning electron microscopy and energy dispersive X-ray spectrometry （SEM/EDS）. Particle size analysis found bimodal distribution at 0.2 and 0.5 μm. The particle morphology was characterized by 14 different shape clusters： square, pentagon, hexagon, heptagon, octagon, nonagon, decagon, agglomerate, sphere, triangle, oblong, strip, line or stick, and unknown, by quantitative order. The square particles were common in the samples. Round and triangle particles are more, and pentagon, hexagon, heptagon, octagon, nonagon, decagon, strip, line or sticks are less. Agglomerate particles were found in abundance. The surface of most particles was coarse with a fractal edge that can provide a suitable chemical reaction bed in the polluted atmospheric environment. The three sorts of surface patterns of squares were smooth, semi-smooth, and coarse. The three sorts of square surface patterns represented the morphological characteristics of single inhalable particles in the air inside the bus in Toledo. The size and shape distribution results were compared to those obtained for a bus using ultra low sulfur diesel.展开更多
In order to further understand the sources of PM2.5 in Shanghai air, the synchrotron X-ray fluores- cence microprobe at the BL-4A Beamline of Photon Factory of High Energy Accelerator Research Organization, Japan, was...In order to further understand the sources of PM2.5 in Shanghai air, the synchrotron X-ray fluores- cence microprobe at the BL-4A Beamline of Photon Factory of High Energy Accelerator Research Organization, Japan, was applied to analyze the individual PM2.5 particles collected from Shanghai air in the winter of 2007. Eight categories of emission sources were recognized in these individual particles. The source identification shows that most of the analyzed PM2.5 particles are derived from vehicle exhaust and metallurgical emissions. This suggests that the important emission sources of PM2.5 in Shanghai air would be vehicle exhaust and metallurgical activities.展开更多
Knowledge of haze particles in background areas of North China is limited, although they have been studied well in urban settings. Atmospheric aerosol particles were collected at a background site in the North China P...Knowledge of haze particles in background areas of North China is limited, although they have been studied well in urban settings. Atmospheric aerosol particles were collected at a background site in the North China Plain during 16–31 January, 2011. Water soluble inorganic ions of PM2.5 and physicochemical characteristics of individual particles on hazy and clean days were measured by Ion Chromatography(IC) and Transmission Electron Microscopy(TEM), respectively. Average PM2.5 mass concentration was 50.4±29.9 μg m?3 with 62.5±26.8 μg m?3 on hazy days and 19.9±11.5 μg m?3 on clean days. SO42?, NO3?, and NH4+ with a combined mass concentration of 19.0±11.5 μg m?3 accounted for 69.8%–89.4% of the total water soluble inorganic ions. Size distributions of SO42? and NH4+ showed one unimodal peak at 0.56–1.8 μm on hazy days, whereas NO3? appeared as bimodal peaks at 0.56–1.8 and 5.6–10 μm, respectively. Individual particle analyses showed that the dominant aerosols were a mixture of sulfate, nitrate, and carbonaceous species, which together determine their mixing states. 48-h air mass back trajectories on hazy days suggested that air masses crossed the polluted continental areas(such as Jing-jin-ji region and Shandong province) and entrained ground air pollutants 11–19 hours before reaching the background area. During long-range transport particles undergo ageing and tend to be internally mixed mainly due to condensation in the background atmosphere. Our results suggest that hygroscopic and optical properties of these aerosol particles in the background area differ substantially from those in urban areas.展开更多
基金supported by the National Basic Research Program of China (973 Program) (No. 2013CB228503)the Projects of International Cooperation and Exchanges NSFC (No. 41571130031)
文摘Coal combustion in the domestic stoves, which is common in most parts of the Chinese countryside, can release harmful substances into the air and cause health issues. In this study, particles emitted from laboratory stove combustion of the raw powder coals were analyzed for morphologies and chemical compositions by using transmission electron microscopy （TEM） coupled with energy-dispersive X-ray spectrometry （EDX）. The coal burning-derived individual particles were classified into two groups： carbonaceous particles （including soot aggregates and organic particles） and non-carbonaceous particles （including sulfate, mineral and metal particles）. The non-carbonaceous particles, which constituted a majority of the coal burning-derived emissions, were subdivided into Si-rich, S-rich, K-rich, Ca-rich, and Fe-rich particles according to the elemental compositions. The Si-rich, S-rich and K-rich particles are commonly observed in the coal burning emission. The proportions for particles of different types exhibit obvious coal-issue dependence. Burning of coal with high ash yield could emit more non-carbonaceous particles, and burning of coal with high sulfur content can emit more S-rich particles. By comparing the S-rich particles from this coal burning experiment with those in the atmosphere, we draw a conclusion that some S-rich particles in the atmosphere in China could be mainly sourced from coal combustion.
基金supported by the National Basic Research Program (973) of China (No.2006CB403701)the Macao Foundation for Development of Science and Technology (No.023/2006/A)+3 种基金the State Key Laboratory of Coal Resources and Safe Mining (China University of Mining and Technology) (No.SKLCRSM09KFB04)the China Postdoctoral Science Foundation Funded Project(No.20090461213)the Shandong Postdoctoral Science Innovation Foundation (No.200902016)the Independent Innovation Foundation of Shandong University
文摘Aerosol samples were collected in summer in Macao, a coastal city of the Pearl River Delta Region in China. Morphology, size, elemental composition, and mixing state of individual aerosol particles were determined by scanning electron microscopy coupled energy dispersive X-ray （SEM/EDX） and transmission electron microscopy （TEM）. Based on the morphologies of 5711 aerosol particles, they consist of soot （32%）, mineral （17%）, secondary-（22%）, and unknown fine particles （29%）. The sizes of these particles were mostly distributed between 0.1 and 0.4 μm. Compositions of 202 mineral particles were obtained by SEM/EDX. Mineral particles were mainly classified into three types： Si-rich, Ca-rich, and Na-rich. The compositions of typical mineral particles can indicate their sources in sampling location. For example, mineral particles, collected along the main street, were associated with trace amounts of heavy metals, such as Zn, Ti, Mn, Ba, Pb, and As. TEM observations indicate that most Na-rich particles were aged sea salt particles （e.g., Na2SO4 and NaNO3） which formed through heterogeneous chemical reactions between sea salt and acidic gases. Additionally, aging time of soot was short in Macao due to high humidity, high temperature, and high levels of sunlight in Macao. Most of soot and fine mineral dust particles were internally mixed with secondary particles.
基金supported by the National Key Research and Development Program of China(No.2022YFC3701103)the National Natural Science Foundation of China(No.42222705)+1 种基金the Youth Innovation Promotion Association CAS(No.2021354)Guangdong Foundation for Program of Science and Technology Research(No.2023B1212060049).
文摘Nitrogen-containing organic compounds(NOCs)may potentially contribute to aqueous secondary organic aerosols,yet the different formation of NOCs in aerosol particles and cloud droplets remains unclear.With the in-situ measurements performed at a mountain site(1690 m a.s.l.)in southern China,we investigated the formation of NOCs in the cloud droplets and the cloud-free particles,based on their mixing state information of NOCscontaining particles by single particle mass spectrometry.The relative abundance of NOCs in the cloud-free particles was significantly higher than those in cloud residual(cloud RES)particles.NOCs were highly correlated with carbonyl compounds(including glyoxalate and methylglyoxal)in the cloud-free particles,however,limited correlation was observed for cloud RES particles.Analysis of their mixing state and temporal variations highlights that NOCs was mainly formed from the carbonyl compounds and ammonium in the cloud-free particles,rather than in the cloud RES particles.The results support that the formation of NOCs from carbonyl compounds is facilitated in concentrated solutions in wet aerosols,rather than cloud droplets.In addition,we have identified the transport of biomass burning particles that facilitate the formation of NOCs,and that the observed NOCs is most likely contributed to the light absorption.These findings have implications for the evaluation of NOCs formation and their contribution to light absorption.
基金supported by the National Natural Science Foundation of China(Nos.21707077,21775042)the National Key Research and Development Program of China(No.2017YFA0207003)the Fundamental Research Funds for the Central Universities(No.2020 MS037)。
文摘The nondestructive characterization of the mixing state of individual fine particles using the traditional single particle analysis technique remains a challenge.In this study,fine particles were collected during haze events under different pollution levels from September 5 to 112017 in Beijing,China.A nondestructive surface-enhanced Raman scattering(SERS)technique was employed to investigate the morphology,chemical composition,and mixing state of the multiple components in the individual fine particles.Optical image and SERS spectral analysis results show that soot existing in the form of opaque material was predominant during clear periods(PM_(2.5)≤75μg/m^(3)).During polluted periods(PM_(2.5)>75μg/m^(3)),opaque particles mixed with transparent particles(nitrates and sulfates)were generally observed.Direct classical least squares analysis further identified the relative abundances of the three major components of the single particles:soot(69.18%),nitrates(28.71%),and sulfates(2.11%).A negative correlation was observed between the abundance of soot and the mass concentration of PM_(2.5).Furthermore,mapping analysis revealed that on hazy days,PM_(2.5)existed as a core-shell structure with soot surrounded by nitrates and sulfates.This mixing state analysis method for individual PM_(2.5)particles provides information regarding chemical composition and haze formation mechanisms,and has the potential to facilitate the formulation of haze prevention and control policies.
文摘Thin film methods and X ray energy dispersive technique were applied to analyze sulfate-containing particles inBeijing in order to examine their features and sources. Atmospheric aerosol particles were collected on electron microscope meshes according to two size ranges: coarse particles (r>0.5μm) and fine particles (0.5μm>r>0. 1μm) by using a two-stage impactor. It was found that more than seventy percent of the fine particles and about twenty percentof the coarse particles were sulfate-containing particles. These particles were formed mainly through heterogeneousnucleation. The element composition analyses revealed that the atmospheric aerosol particles in Beijing were domi-nated by crustal particles and construction dust.
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supported by the Natural Science Foundation of Hebei Province(Nos.B2022407001 and D2021501004)the National Natural Science Foundation of China(No.42075107)the Fundamental Research Funds for the Central Universities(No.N2223011).
文摘An intense Asian dust storm invadedQinhuangdao,a coastal city ofNorth China on April 11-14,2023.We analyzed the bulk water-soluble inorganic ions(WSII)of PM_(10)and PM_(2.5)using an Ion Chromatograph and investigated individual particlemorphology and elemental composition using a scanning electron microscope coupled with energy dispersive X-ray.The results showed when the dust was directly transported to the sampling site from northwestern China(direct transport stages),the PM_(10)mass concentrations were high(675.0μg/m^(3))but the relative humidity(RH)was low.Total WSII were 19.54μg/m^(3)and 11.17μg/m^(3),accounting for 2.90%and 7.25%of the PM_(10)and PM_(2.5),respectively.In addition,the proportion of S-containing individual mineral dust was low(28.7%-35.3%).The results suggested there were limited secondary inorganic aerosol formation.However,when the dust was transported back to the sampling site across the Bohai Sea in the following days(reverse transport stages),both the PM_(10)mass concentrations(462.3μg/m^(3))and RH were high.Total WSII were 43.75μg/m^(3)and 18.71μg/m^(3),accounting for 9.62%and 14.45%of the total PM_(10)and PM_(2.5),respectively.The proportion of S-containing particles was 51.5%-72.5%.In addition,the concentration of NO_(3)^(−)was much higher than that of SO_(4)^(2−).The results suggested both the sulfate and nitrate formation occurred on coarse mineral dust but the nitrate formation exceeded sulfate formation.Interestingly,mostmineral dust,including Sirich particles contained Cl when they passed through the marine atmosphere.The results highlighted the heterogeneous reactions of dust varied in different transport stages.
基金provided by the National Natural Science Foundation of China (Nos. 21177026, 21190053, 40975074)the Ministry of Education of new century talent project (NCET11-0104)+1 种基金the Doctoral Fund of Ministry of Education (No. 2013007111008)the Pujiang Talent Program of Shanghai (No. PJ[2010]00317)
文摘To understand the composition and major sources of aerosol particles in Lhasa City on the Tibetan Plateau （TP）, individual particles were collected from 2 February to 8 March, 2013 in Tibet University. The mean concentrations of both PM2.5 and PM10 during the sampling were 25.7 ± 21.7 and 57.2 ± 46.7 μg/m^3, respectively, much lower than those of other cities in East and South Asia, but higher than those in the remote region in TP like Nam Co, indicating minor urban pollution. Combining the observations with the meteorological parameters and back trajectory analysis, it was concluded that local sources controlled the pollution during the sampling. Transmission electron microscopy （TEM） combined with energydispersive X-ray spectra （EDS） was used to study 408 particles sampled on four days. Based on the EDS analysis, a total of 8 different particle categories were classified for all 408 particles, including Si-rich, Ca-rich, soot, K-rich, Fe-rich, Pb-rich, Al-rich and other particles. The dominant elements were Si, A1 and Ca, which were mainly attributed to mineral dust in the earth＇s crust such as feldspar and clay. Fe-, Pb-, K-, Al-rich particles and soot mainly originated from anthropogenic sources like firework combustion and biomass burning during the sampling. During the sampling, the pollution mainly came from mineral dust, while the celebration ceremony and religious ritual produced a large quantity of anthro- pogenic metal-bearing particles on 9 and 25 February 2013. Cement particles also had a minor influence. The data obtained in this study can be useful for developing pollution control strategies.
基金supported by the National Natural Science Foundation of China (Nos. 41805099,91844301)the China Postdoctoral Science Foundation (No. 2018M632449)the Zhejiang Provincial Natural Science Foundation of China (No. LZ19D050001)。
文摘In recent decades, coastal ports have experienced rapid development and become an important economic and ecological hub in China. Atmospheric particle is a research hotspot in atmospheric environmental sciences in inland regions. However, few studies on the atmospheric particle were conducted in coastal port areas in China, which indeed suffers atmospheric particle pollution. Lack of the physicochemical characteristics of fine particles serves as an obstacle toward the accurate control for air pollution in the coastal port area in China. Here, a field observation was conducted in an important coastal port city in Yangtze River Delta from March 6 to March 19, 2019. The average PM2.5 concentration was 63.7 ±27.8 μg/m^3 and NO3^-, SO4^2-, NH4^+, and organic matter accounted for ?60% of PM 2.5. Fe was the most abundant trace metal element and V as the ship emission indicator was detected. Transmission electron microscopy images showed that SK-rich, soot, Fe, SK-soot and SK-Fe were the major individual particles in the coastal port. V and soluble Fe were detected in sulfate coating of SK-Fe particles. We found that anthropogenic emissions, marine sea salt, and secondary atmosphere process were the major sources of fine particles. Backward trajectory analysis indicated that the dominant air masses were marine air mass, inland air mass from northern Zhejiang and inland-marine mixed air mass from Shandong and Shanghai during the sampling period. The findings can help us better understand the physicochemical properties of atmospheric fine particles in the coastal port of Eastern China.
基金supported by the Chinese Ministry of Science and Technology(No.2008AA062503)the National Natural Science Foundation Committee of China(Nos.41421064,20637020)the China Postdoctoral Science Foundation(No.20100470166)
文摘Heterogeneous reactions on the aerosol particle surface in the atmosphere play important roles in air pollution, climate change, and global biogeochemical cycles. However, the reported uptake coefficients of heterogeneous reactions usually have large variations and may not be relevant to real atmospheric conditions. One of the major reasons for this is the use of bulk samples in laboratory experiments, while particles in the atmosphere are suspended individually. A number of technologies have been developed recently to study heterogeneous reactions on the surfaces of individual particles. Precise measurements on the reactive surface area, volume, and morphology of individual particles are necessary for calculating the uptake coefficient, quantifying reactants and products, and understanding the reaction mechanism better. In this study, for the first time we used synchrotron radiation X-ray computed tomography（XCT） and micro-Raman spectrometry to measure individual CaCO_3 particle morphology, with sizes ranging from 3.5–6.5 μm. Particle surface area and volume were calculated using a reconstruction method based on software threedimensional（3-D） rendering. The XCT was first validated with high-resolution fieldemission scanning electron microscopy（FE-SEM） to acquire accurate CaCO_3 particle surface area and volume estimates. Our results showed an average difference of only 6.1% in surface area and 3.2% in volume measured either by micro-Raman spectrometry or X-ray tomography. X-ray tomography and FE-SEM can provide more morphological details of individual Ca CO3 particles than micro-Raman spectrometry. This study demonstrated that X-ray computed tomography and micro-Raman spectrometry can precisely measure the surface area, volume, and morphology of an individual particle.
基金supported by the National Natural Science Foundation of China(Nos.42307143,42307127,and 42307141)Shandong Provincial Natural Science Foundation(Nos.ZR2023QD151,ZR2024QD160,and ZR2023QD094)+2 种基金Zhejiang Province Basic Public Welfare Research Program Project(No.LGC22B050009)the Ph.D.Research Startup Foundation of Shandong University of Aeronautics(No.2022Y19)LAC/CMA(No.2023B10)。
文摘Atmospheric metal pollution is a significant environmental issue in China.Understanding the microscopic characteristics of metallic elements are crucial for investigating their sources and health effects,but this information is still limited.In this study,transmission electron microscopy(TEM)combined with bulk analysis method were employed to investigate the microscopic characteristics and mass concentrations of atmospheric metallic elements at a village site and an urban site located in North China Plain during wintertime.Our results reveal that the total mass concentrations of 16 metallic elements(including nine toxic heavy metallic elements)in PM_(2.5)were 3439.18±1101.24 ng/m^(3)(1129.6±376.85 ng/m^(3))at the village site and 3555.1±916.71 ng/m^(3)(1295.26±446.39 ng/m^(3))at urban site,accounting for 2.23%and 2.76%of PM_(2.5),respectively.We found that K,Ca,and Fe were the dominant elements,constituting over 75%of total metal mass.TEM analysis indicates that these metallic elements were mainly enriched in six types of individual particles,including K-rich,mineral,fly ash,Fe-rich,Zn-rich,and Pb-rich particles.Mineral particles were predominant in all individual metal particles at urban site,while K-rich particles became the dominant metal particles influenced by residential biomass burning at village site.Moreover,we found toxic metal particles(Fe-rich,Zn-rich,Pb-rich,and fly ash)presented smaller mean sizes(243 nm)in village air compared to urban air(337 nm),suggesting that metal particles in village air might pose a higher health risk to the residents.These results emphasize that atmospheric metal pollution in the village areas need more attentions in the future.
基金financially supported by the National Natural Science Foundation of China(20637020,40490265&20077001)National Basic Research Program of China(2002CB410802)special fund of State Key Joint Laboratory of Environment Simulation and Pollution Control
文摘Investigating the heterogeneous reaction on individual atmospheric particles is important because it approximates actual atmospheric conditions and can aid in reducing artifacts in elucidating real mechanisms and processes,and determining real kinetic parameters of the atmosphere relevance.This study developed a Raman microspectrometry method to investigate heterogeneous reactions on individual particles.The method was applied to the reaction of NO2 with individual CaCO3 particles.It was demonstrated that Raman microspectrometry can obtain information on both chemical composition and microscopic morphology at the same time,as well as information on chemical characteristics,such as the phase,which is useful for studying reaction processes.Raman spectra of individual particles deposited on a substrate showed no interference by morphological resonance,which is helpful for obtaining high-quality spectra.Moreover,Raman microspectrometry was compared with other methods for investigating heterogeneous reactions on individual particles and was found to have several advantageous characteristics.
基金supported in a part by Chinese National Key Project of Basic Research (No G2000048703)the Grant-in-Aid for Scientific Research (No 16310008,18403002) from the Ministry of Education, Culture,Sports, Science and Technology, Japan
文摘Recent observations of Asian dust storms show an eastern expansion of the source area to degraded lands, where dust emissions have been little studied. The dust concentrations over the saline land of the western Songnen Plain （SSL）, Northeastern China, are circumstantially higher than those from the northwestern Chinese deserts. These concentrations are sensitive to the surface soil conditions and wind velocity on the ground. The dust samples collected during dust storm events on the SSL contain abundant Na, Mg, A1, K, Ca, Fe and Ti, as well as toxic elements such as Cu, V, Zn and Ba. Individual particle analysis reveals that fine saline particles （〈 10 μm in diameter） on the saline land, consisting largely of carbonate, halite and sulfate together with lithogenic minerals such as SiO2 and aluminosilicate, are eventually uplifted during the interval from spring to autuum. The predominantly fine saline particles uplifted from the SSL are likely transported eastward by the winter monsoon circulation and westerlies. Recent degradation of saline lands in Northeastern China would not only increase the frequency of dust storm events in the downwind area, but also might change the chemical composition of the Asian dust emissions.
文摘In an urban-transit bus, fueled by biodiesel in Toledo, Ohio, single inhalable particle samples in October 2008 were collected and detected by scanning electron microscopy and energy dispersive X-ray spectrometry （SEM/EDS）. Particle size analysis found bimodal distribution at 0.2 and 0.5 μm. The particle morphology was characterized by 14 different shape clusters： square, pentagon, hexagon, heptagon, octagon, nonagon, decagon, agglomerate, sphere, triangle, oblong, strip, line or stick, and unknown, by quantitative order. The square particles were common in the samples. Round and triangle particles are more, and pentagon, hexagon, heptagon, octagon, nonagon, decagon, strip, line or sticks are less. Agglomerate particles were found in abundance. The surface of most particles was coarse with a fractal edge that can provide a suitable chemical reaction bed in the polluted atmospheric environment. The three sorts of surface patterns of squares were smooth, semi-smooth, and coarse. The three sorts of square surface patterns represented the morphological characteristics of single inhalable particles in the air inside the bus in Toledo. The size and shape distribution results were compared to those obtained for a bus using ultra low sulfur diesel.
基金Supported by Knowledge Innovation Project of Chinese Academy of Sciences (KJCX3.SYW.N3) National Natural Science Foundation of China (10775172, 10675159)performance under approval of Photon Factory (PF) Program Advisory Committee(Proposal No.2007G502)
文摘In order to further understand the sources of PM2.5 in Shanghai air, the synchrotron X-ray fluores- cence microprobe at the BL-4A Beamline of Photon Factory of High Energy Accelerator Research Organization, Japan, was applied to analyze the individual PM2.5 particles collected from Shanghai air in the winter of 2007. Eight categories of emission sources were recognized in these individual particles. The source identification shows that most of the analyzed PM2.5 particles are derived from vehicle exhaust and metallurgical emissions. This suggests that the important emission sources of PM2.5 in Shanghai air would be vehicle exhaust and metallurgical activities.
基金supported by Distinguished Youth Foundation of Shandong Provin c e(Grant No.JQ20 1413)the Scientific Research Staring Foundation for the Institute of Arid Meteorology,China Meteorology Administration(Grant No.KYS2014SSKY05)+2 种基金the National Basic Research Program of China(Grant No.2011CB403401)Fundamental Research Funds of Shandong University(Grant No.2014QY001)State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry(Grant No.LAPC-KF-2014-03)
文摘Knowledge of haze particles in background areas of North China is limited, although they have been studied well in urban settings. Atmospheric aerosol particles were collected at a background site in the North China Plain during 16–31 January, 2011. Water soluble inorganic ions of PM2.5 and physicochemical characteristics of individual particles on hazy and clean days were measured by Ion Chromatography(IC) and Transmission Electron Microscopy(TEM), respectively. Average PM2.5 mass concentration was 50.4±29.9 μg m?3 with 62.5±26.8 μg m?3 on hazy days and 19.9±11.5 μg m?3 on clean days. SO42?, NO3?, and NH4+ with a combined mass concentration of 19.0±11.5 μg m?3 accounted for 69.8%–89.4% of the total water soluble inorganic ions. Size distributions of SO42? and NH4+ showed one unimodal peak at 0.56–1.8 μm on hazy days, whereas NO3? appeared as bimodal peaks at 0.56–1.8 and 5.6–10 μm, respectively. Individual particle analyses showed that the dominant aerosols were a mixture of sulfate, nitrate, and carbonaceous species, which together determine their mixing states. 48-h air mass back trajectories on hazy days suggested that air masses crossed the polluted continental areas(such as Jing-jin-ji region and Shandong province) and entrained ground air pollutants 11–19 hours before reaching the background area. During long-range transport particles undergo ageing and tend to be internally mixed mainly due to condensation in the background atmosphere. Our results suggest that hygroscopic and optical properties of these aerosol particles in the background area differ substantially from those in urban areas.
