Measurements of atmospheric aerosols and trace gases using the laser radar (lidar) techniques, have been in progress since 1985 at the Indian Institute of Tropical Meteorology, Pune (18°32'N, 73°51'E...Measurements of atmospheric aerosols and trace gases using the laser radar (lidar) techniques, have been in progress since 1985 at the Indian Institute of Tropical Meteorology, Pune (18°32'N, 73°51'E, 559 m AMSL), India. These observations carried out during nighttime in the lower atmosphere (up to 5.5 km AGL), employing an Argon ion / Helium-Neon lidar provided information on the nature, size, concentration and other characteristics of the constituents present in the tropical atmosphere. The time-height variations in aerosol concentration and associated layer structure exhibit marked differences between the post-sunset and pre-sunrise periods besides their seasonal variation with maximum concentration during pre-monsoon / winter and minimum concentration during monsoon months. These observations also revealed the influence of the terrain of the experimental site and some selected meteorological parameters on the aerosol vertical distributions. The special observations of aerosol vertical profiles obtained in the nighttime atmospheric boundary layer during October 1986 through September 1989 showed that the most probable occurrence of mixing depth lies between 450 and 550 m, and the multiple stably stratified aerosol layers present above the mixing depth with maximum frequency of occurrence at around 750 m. This information on nighttime mixing depth / stable layer derived from lidar aerosol observations showed good agreement with the height of the ground-based shear layer / elevated layer observed by the simultaneously operated sodar at the lidar site.展开更多
By using the probe data of two sorties airplane in the middle and southern parts of Hebei Province in 2007 spring,the characteristics of atmospheric aerosol particles concentration and size distribution in the area in...By using the probe data of two sorties airplane in the middle and southern parts of Hebei Province in 2007 spring,the characteristics of atmospheric aerosol particles concentration and size distribution in the area in the cloudy day situation were analyzed.The results showed that the overall trend of aerosol particles concentration in the weather systems which included the south branch trough and North China low vortex was the decrease as the height increased.However,if the cirrostratus was in the high altitude,it increased as the height increased.In the bottom of inversion layer,there existed the obvious accumulation of aerosol and cloud droplet.Affected by the complex weather systems,the aerosol particle size distribution presented the multi-peak type for the disturbance of updraft or turbulence.展开更多
Atmospheric concentrations of polycyclic aromatic hydrocarbons (PAHs) were measured during various seasons at six different cities/locations in Qingdao alongshore. The annual average PAHs concentration ranged from 16 ...Atmospheric concentrations of polycyclic aromatic hydrocarbons (PAHs) were measured during various seasons at six different cities/locations in Qingdao alongshore. The annual average PAHs concentration ranged from 16 ng/m3 (at a clean com- pared site) to 308 ng/m3 (in an industry site). The average total particulate PAHs concentration was 74.5 ng/m3 with a higher concentration of particulate PAHs in winter. Based on a year-round dataset, the sources of PAHs in the air of Qingdao were drawn by principal factor analysis and correlation analysis. The results indicated that vehicle emissions and oil burning were the main source of PAHs in Qingdao alongshore.展开更多
To investigate the impact on urban air pollution by crop residual burning outside Nanjing, aerosol concentration, pollution gas concentration, mass concentration, and water-soluble ion size distribution were observed ...To investigate the impact on urban air pollution by crop residual burning outside Nanjing, aerosol concentration, pollution gas concentration, mass concentration, and water-soluble ion size distribution were observed during one event of November 4-9, 2010. Results show that the size distribution of aerosol concentration is bimodal on pollution days and normal days, with peak values at 60- 70 and 200-300 nm, respectively. Aerosol concentration is 104 cm-3.nm-1 on pollution days. The peak value of spectrum distribution of aerosol concentration on pollution days is 1.5-3.3 times higher than that on a normal day. Crop residual burning has a great impact on the concentration of fine particles. Diurnal variation of aerosol concentration is trimodal on pollution days and normal days, with peak values at 03：00, 09：00 and 19：00 local standard time. The first peak is impacted by meteorological elements, while the second and third peaks are due to human activities, such as rush hour traffic. Crop residual burning has the greatest impact on SO2 concentration, followed by NO2, 03 is hardly affected. The impact of crop residual burning on fine particles （〈 2.1 μm） is larger than on coarse particles （〉 2.1 μm）, thus ion concentration in fine particles is higher than that in coarse particles. Crop residual burning leads to similar increase in all ion components, thus it has a small impact on the water-soluble ions order. Crop residual burning has a strong impact on the size distribution of K^＋, Cl^-, Na^＋, and F- and has a weak impact on the size distributions of NH4^＋, Ca^2＋, NO3^- and SO4^2-.展开更多
The aerosol number spectrum and gas pollutants were measured and the new particle formation （NPF） events were discussed in Nanjing. The results showed that the size distributions of aerosol number concen- trations e...The aerosol number spectrum and gas pollutants were measured and the new particle formation （NPF） events were discussed in Nanjing. The results showed that the size distributions of aerosol number concen- trations exhibited distinct seasonal variations, implying the relations of particle sizes and their sources and sinks. The number concentrations of particles in the nuclei mode （10-30 nm）, Aitken mode （30-100 nm）, accumulation mode （100 -1000 nm） and coarse mode （〉1μm） varied in the order of summer 〉 spring 〉 autumn, summer 〉 autumn 〉 spring, autumn 〉 summer 〉 spring, and spring 〉 autumn 〉summer, re- spectively. The diurnal variation of total aerosol number concentrations showed three peaks in all observed periods, which corresponded to two rush hours and the photochemistry period at noon. In general, the NPF in summer occurred under the conditions of east winds and dominant air masses originating from marine areas with high relative humidity （50%-70%） and strong solar radiations （400 -700 W m-2）. In spring, the NPF were generally accompanied by low relative humidity （14%-30%） and strong solar radiations （400-600 W m-2）. The new particle growth rates （GR） were higher in the summertime in the range of 10- 16 nm h-1. In spring, the GR were 6.8-8.3 nm h-1. Under polluted air conditions, NPF events were seldom captured in autumn in Nanjing. During NPF periods, positive correlations between 10- 30 nm particles and 03 were detected, particularly in spring, indicating that NPF can be attributed to photochemical reactions.展开更多
Number concentration and size distribution of atmospheric aerosols were measured in Beijing by an optical particle counter. The relationship between aerosol size distribution and relative humidity is discussed. The re...Number concentration and size distribution of atmospheric aerosols were measured in Beijing by an optical particle counter. The relationship between aerosol size distribution and relative humidity is discussed. The results show that the size distribution, diurnal variation, daily variation of atmospheric aerosols have a good relation to relative humidity and Richardson number. Key words Atmospheric aerosol - Number concentration - Size distribution - Relative humidity - Richardson number This work is financially supported by NKBRSF Project (G1999043400), Knowledge Creative Project (8-2101 and 82303) founded by TAP, CAS.The authors would like to express their thanks to Prof. Zhang Wen for his work in this observation.展开更多
Measurements of aerosol physical, chemical and optical parameters were carried out in Guangzhou, China from 1 July to 31 July 2006 during the Pearl River Delta Campaign. The dry aerosol scattering coefficient was meas...Measurements of aerosol physical, chemical and optical parameters were carried out in Guangzhou, China from 1 July to 31 July 2006 during the Pearl River Delta Campaign. The dry aerosol scattering coefficient was measured using an integrating nephelometer and the aerosol scattering coefficient for wet conditions was determined by subtracting the sum of the aerosol absorption coefficient, gas scattering coefficient and gas absorption coefficient from the atmospheric extinction coefficient. Following this, the aerosol hygroscopic growth factor, f（RH）, was calculated as the ratio of wet and dry aerosol scattering coefficients. Measurements of size-resolved chemical composition, relative humidity （RH）, and published functional relationships between particle chemical composition and water uptake were likewise used to find the aerosol scattering coe？cients in wet and dry conditions using Mie theory for internally- or externally-mixed particle species [（NH_4）_2SO_4, NH_4NO_3, NaCl, POM, EC and residue]. Closure was obtained by comparing the measured f（RH） values from the nephelometer and other in situ optical instruments with those computed from chemical composition and thermodynamics. Results show that the model can represent the observed f（RH） and is appropriate for use as a component in other higher-order models.展开更多
Size–fractioned atmospheric aerosol particles were collected during a typical heavy air pollution event in Beijing. The organic and inorganic components on the surfaces of the samples were analyzed using time–of–fl...Size–fractioned atmospheric aerosol particles were collected during a typical heavy air pollution event in Beijing. The organic and inorganic components on the surfaces of the samples were analyzed using time–of–flight secondary ion mass spectrometry（TOF–SIMS）.The variation characteristics of the surface chemical composition and influencing factors were studied, and the possible sources of these chemical compositions were identified through principal component analysis. The results showed that inorganic components such as crustal elements and sulfate, and organic components such as aliphatic hydrocarbons and oxygen–containing organic groups were present. Some surface components, such as polycyclic aromatic hydrocarbons, heavy metals and fluorides may exert adverse effects on human health. The species and relative percentages of the chemical components varied with particle size, diurnal and pollution progress. During a heavy pollution event, the species and relative percentages of secondary components such as oxygen–containing organic groups and sulfurous compounds increased, indicating that particles aged during this event. The surface chemical composition of the aerosol particles was affected mainly by emissions from coal combustion and motor vehicles. In addition, air pollution, meteorological factors, and air mass transport also exerted a significant effect on the surface chemical composition of aerosol particles.展开更多
Particle density is an important physical property of atmospheric particles. The information on high time-resolution size-resolved particle density is essential for understanding the atmospheric physical and chemical ...Particle density is an important physical property of atmospheric particles. The information on high time-resolution size-resolved particle density is essential for understanding the atmospheric physical and chemical aging processes of aerosols particles. In the present study, a centrifugal particle mass analyzer （CPMA） combined with a differential mobility analyzer （DMA） was deployed to determine the size-resolved effective density of 50 to 350 nm particles at a rural site of Beijing during summer 2016. The measured particle effective densities decreased with increasing particle sizes and ranged from 1.43 to 1.55 g/cm3, on average. The effective particle density distributions were dominated by a mode peaked at around 1.5 g/cm3 for 50 to 350 nm particles. Extra modes with peaks at 1.0, 0.8, and 0.6 g/cm3 for 150, 240, and 350 nm particles, which might be freshly emitted soot particles, were observed during intensive primary emissions episodes. The particle effective densities showed a diurnal variation pattern, with higher values during daytime. A case study showed that the effective density of Aitken mode particles during the new particle formation （NPF） event decreased considerably, indicating the significant contribution of organics to new particle growth.展开更多
Atmospheric aerosol particle samples were collected using an Ambient Eight Stage（Non-Viable） Cascade Impactor Sampler in a typical urban area of Beijing from 27 th Sep.to 5th Oct.,2009.The surface chemistry of these...Atmospheric aerosol particle samples were collected using an Ambient Eight Stage（Non-Viable） Cascade Impactor Sampler in a typical urban area of Beijing from 27 th Sep.to 5th Oct.,2009.The surface chemistry of these aerosol particles was analyzed using Static Time of Flight-Secondary Ion Mass Spectrometry（Static TOF-SIMS）.The factors influencing surface compositions were evaluated in conjunction with the air pollution levels,meteorological factors,and air mass transport for the sampling period.The results show that a variety of organic ion groups and inorganic ions/ion groups were accumulated on the surfaces of aerosol particles in urban areas of Beijing;and hydrophobic organic compounds with short-or middle-chain alkyl as well as hydrophilic secondary inorganic compounds were observed.All these compounds have the potential to affect the atmospheric behavior of urban aerosol particles.PM1.1–2.1and PM3.3–4.7had similar elements on their surfaces,but some molecules and ionic groups demonstrated differences in Time of Flight-Secondary Ion Mass Spectrometry spectra.This suggests that the quantities of elements varied between PM1.1–2.1and PM3.3–4.7.In particular,more intense research efforts into fluoride pollution are required,because the fluorides on aerosol surfaces have the potential to harm human health.The levels of air pollution had the most significant influence on the surface compositions of aerosol particles in our study.Hence,heavier air pollution was associated with more complex surface compositions on aerosol particles.In addition,wind,rainfall,and air masses from the south also greatly influenced the surface compositions of these urban aerosol particles.展开更多
Amino acids(AAs)including D-and L-enantiomers are a group of organic nitrogen species in ambient aerosol.Due to the low abundances of AAs(level of ng/m^(3))and the matrix effects by coexistent components,it is challen...Amino acids(AAs)including D-and L-enantiomers are a group of organic nitrogen species in ambient aerosol.Due to the low abundances of AAs(level of ng/m^(3))and the matrix effects by coexistent components,it is challenging to quantify AA enantiomers in ambient aerosols especially under pollution conditions.In this study,we present an optimized method for analyzing AA enantiomers in atmospheric aerosol samples including a pretreatment process and the detection by high performance liquid chromatography coupled to a fuorescence detector(HPLC-FLD).Matrix effects caused by coexistent chemicals on AA enantiomers analysis in ambient aerosol samples were investigated especially for those collected in pollution episodes.The results revealed that the determination of AA enantiomers is significantly affected by the coexistent organic carbon(as a proxy of organic matter)and water-soluble ion of NH_(4)^(+).To remove the matrix effects,we applied a pretreatment using the solid phase extraction column coupled with alkaline adjustment to sample extract.After pretreatment,18 AAs including 6 pairs of D-and L-enantiomers(i.e.,leucine,isoleucine,valine,alanine,serine,and aspartic acid)can be successfully separated and quantified in aerosol samples by HPLC-FLD.The recoveries are in the range of 67%-106%.This method was successfully applied to the urban aerosol samples from pollution and non-pollution periods for AA enantiomers determination.We suggest that the concentrations of D-AAs and the ratio of D-AA/L-AA are indicative of the contribution of bacterial sources and the infuence of biomass burning.展开更多
The chemical composition of atmospheric aerosols has been investigated. Contributions ofsulfate and soot in aerosols to the atmospheric extinction are studied. Discussions are made on the problems of aerosol emitted f...The chemical composition of atmospheric aerosols has been investigated. Contributions ofsulfate and soot in aerosols to the atmospheric extinction are studied. Discussions are made on the problems of aerosol emitted from volcano, forest fires in northern China, 1987 and oil field fires in Kuwait, 1991. It is indicated that the changes in concentration, particle size, and chemical composition of aerosol after those events could have impacts on the climate change either regionally or globally and that the impact of aerosol particles on climate change could compensate for some temperature increase caused by greenhouse gases and the increase of surface intensity of ultraviolet radiation due to ozone layer depletion.展开更多
Solar ultraviolet radiation reaching the ground can be reduced due to light scattering of atmospheric aerosols. Aerosol pollution has led to the decrease in biological active UV-B radiation by about 45% and 10% in cit...Solar ultraviolet radiation reaching the ground can be reduced due to light scattering of atmospheric aerosols. Aerosol pollution has led to the decrease in biological active UV-B radiation by about 45% and 10% in city and rural areas, respectively. In populated areas, effect of aerosol scattering on UV-B radiation may offset the increased amount of UV-B caused by ozone depletion, but in clean areas such as two poles, ozone depletion may have great damage effects on ecosystems.展开更多
The environmental impact of aerosols is currently a hot issue that has received worldwide attention. Lacking simultaneous observations of aerosols and carbon flux, the understanding of the aerosol radiative effect of ...The environmental impact of aerosols is currently a hot issue that has received worldwide attention. Lacking simultaneous observations of aerosols and carbon flux, the understanding of the aerosol radiative effect of urban agglomeration on the net ecosystem carbon exchange(NEE) is restricted. In 2009-2010, an observation of the aerosol optical property and CO_(2) flux was carried out at the Dongguan Meteorological Bureau Station(DMBS) using a sun photometer and eddy covariance systems. The different components of photosynthetically active radiation(PAR),including global PAR(GPAR), direct PAR(DPAR), and scattered PAR(FPAR), were calculated using the Santa Barbara DISORT Atmospheric Radiative Transfer(SBDART) model. The effects of PAR on the NEE between land-atmosphere systems were investigated. The results demonstrated that during the study period the aerosol optical depth(AOD)reduced the DPAR by 519.28±232.89 μmol photons · m^(-2)s^(-1), but increased the FPAR by 324.93±169.85μmol photons ·m^(-2)s^(-1),ultimately leading to 194.34±92.62 μmol photons · m^(-2)s^(-1);decrease in the GPAR. All the PARs(including GPAR,DPAR, and FPAR) resulted in increases in the NEE(improved carbon absorption), but the FPAR has the strongest effect with the light use efficiency(LUE) being 1.12 times the values for the DPAR. The absorption of DPAR by the vegetation exhibited photo-inhibition in the radiation intensity > 600 photons · m^(-2)s^(-1);in contrast, the absorptions of FPAR did not exhibit apparent photo-inhibition. Compared with the FPAR caused by aerosols, the DPAR was not the primary factor affecting the NEE. On the contrary, the increase in AOD significantly increased the FPAR, enhancing the LUE of vegetation ecosystems and finally promoting the photosynthetic CO_(2) absorption.展开更多
As a vital type of light-absorbing aerosol,brown carbon(BrC)presents inherent associations with atmospheric photochemistry and climate change.However,the understanding of the chemical and optical properties of BrC is ...As a vital type of light-absorbing aerosol,brown carbon(BrC)presents inherent associations with atmospheric photochemistry and climate change.However,the understanding of the chemical and optical properties of BrC is limited,especially in some resource-dependent cities with long heating periods in northwest China.This study showed that the annual average abundances of Water-soluble BrC(WS-BrC)were 9.33±7.42 and 8.69±6.29μg/m^(3)in Baotou and Wuhai and the concentrations,absorption coefficient(Abs_(365)),and mass absorption efficiency(MAE365)of WS-BrC presented significant seasonal patterns,with high values in the heating season and low values in the non-heating season;while showing opposite seasonal trends for the Absorption Angstr?m exponent(AAE_(300-400)).Comparatively,the levels of WS-BrC in developing regions(such as cities in Asia)were higher than those in developed regions(such as cities in Europe and Australia),indicating the significant differences in energy consumption in these regions.By combining fluorescence excitation-emission matrix(EEM)spectra with the parallel factor(PARAFAC)model,humic-like(C1 and C2)and proteinlike(C3)substances were identified,and accounted for 61.40%±4.66%and 38.6%±3.78%at Baotou,and 60.33%±6.29%and 39.67%±4.17%at Wuhai,respectively.The results of source apportionment suggested that the potential source regions of WS-BrC varied in heating vs.non-heating seasons and that the properties of WS-BrC significantly depended on primary emissions(e.g.,combustion emissions)and secondary formation.展开更多
Based on observing data of atmospheric aerosol in the north suburban area of Nanjing from September to November in 2007, the number concentration, mass concentration, size distribution and optical properties of atmosp...Based on observing data of atmospheric aerosol in the north suburban area of Nanjing from September to November in 2007, the number concentration, mass concentration, size distribution and optical properties of atmospheric aerosol particles and the relation to meteorological factors were analyzed, and their concentration and optical properties during hazy and non-hazy days were compared. The results showed that aerosol pollution was serious in autumn in this region; the deterioration of visibility had close correlation to fine particles, that is, the average number concen- tration of aerosol was 17 044.2 cm^-3, in which ultra fine particles accounted for 64.3%; the daily average mass concentration of PM2.5 was 281 μg/m3, and the ratio of PM2.5 to PM10 was 0.74; the accumulation mode particles dominated in number and surface concentration distributions, while the volume concentration distribution presented a main peak at size of 1.0 -2.8 μm; fine particles increased during hazy days compared with non-hazy days; the scatter coefficient closely correlated to the particle size, concentration and atmospheric humidity. It was also indicated that meteorological conditions played a critical role in formation of hazy weather, that is, weak large-scale weather systems, low wind speed, high humidity and strong inversion were favorable conditions for hazy weather in autumn.展开更多
Dear Colleagues, We would like to invite you to submit manuscripts to a special issue entitled ＂Current Research on Atmospheric Aerosols and Trace Gases over the Polar Regions＂ of the Journal Advances in Polar Scie...Dear Colleagues, We would like to invite you to submit manuscripts to a special issue entitled ＂Current Research on Atmospheric Aerosols and Trace Gases over the Polar Regions＂ of the Journal Advances in Polar Science （APS）. APS is an international, peer-reviewed journal jointly sponsored by the Polar Research Institute of China （PRIC） and the Chinese Arctic and Antarctic Administration （CAA）. It is a quarterly journal published in March, June, September and December by Science Press of China and circulated internationally （ISSN 1674-9928, CN 31-2050/P）. Articles published in APS are free of charge with generous funding from PRIC. For more details, please visit the APS＇s websites. Thank you in advance for your consideration to submit manuscripts to this special issue, and we encourage you to share this announcement broadly with interested colleagues.展开更多
Taking the Phyllostachys heterocycla forest in Qishan National Forest Park of Fuzhou for example, this study observed the diurnal variation of atmospheric aerosol particles in the forest in the growing season.The resu...Taking the Phyllostachys heterocycla forest in Qishan National Forest Park of Fuzhou for example, this study observed the diurnal variation of atmospheric aerosol particles in the forest in the growing season.The results showed that:(1) The diurnal variation curves of the particle concentration of the forest and the forest edge had "two peaks and two troughs", but the peaks and troughs of the forest edge were advanced or delayed.The concentrations of the particles in the forest and at the forest edge had two peaks at 11:00–13:00 and 17:00–19:00 and two troughs at 7:00–9:00 and 15:00–17:00.(2) For the forest and the forest edge, the diurnal variation trends of the particles of different particle sizes were generally similar, except that the peaks and troughs of fine particles were slightly earlier or lagging than that of coarse particles.(3) The concentrations of the particles were positively correlated with temperature, humidity and light, and negatively correlated with wind speed, and the concentrations of the particles at the forest edge were significantly negatively correlated with wind speed.展开更多
In recent years,haze has posed a serious threat to the global climate change,ecological balance and human health.In this study,the laboratory experiments and field observations were performed and a possible charging m...In recent years,haze has posed a serious threat to the global climate change,ecological balance and human health.In this study,the laboratory experiments and field observations were performed and a possible charging mechanism was proposed to investigate the space charge properties in haze events.The laboratory experiments showed that the charge polarity of primary aerosol is determined by species of combustion fuels while the magnitude is dependent on the combustion completeness.The field observations revealed that the space charge of atmosphere aerosol in haze events differs from that of fair weather and is closely related to PM2.5 concentration when Relative Humidity(RH)<60%,with 1 to 2 orders of magnitude less than the case when RH≥60%.The analysis of equivalent chargeto-mass ratio(ECTM)suggested that in haze events the space charge is governed by primary aerosol emitted by combustion of fossil fuel in a low relative humidity,whereas it is manipulated by the secondary chemical reaction of atmosphere aerosol in a high relative humidity.And we can identify the main pollutants in haze events according to the polarity of atmosphere aerosol and quickly take measures when RH<60%.Accordingly,the dusthaze of RH<80% can be divided into dry-dust-haze when RH<60%and wet-dust-haze when 60%≤RH<80%.Our study firstly elucidated the space charge properties of atmosphere aerosol in haze events and can provide a new perspective for the prevention and control of air pollution.展开更多
In this paper,two different diameter particles(TSP,PM10)were collected by TH-16A four-channels classification air sampler.The samples were treated by HNO3.Analysis of cadmium was carried out by hydride generation atom...In this paper,two different diameter particles(TSP,PM10)were collected by TH-16A four-channels classification air sampler.The samples were treated by HNO3.Analysis of cadmium was carried out by hydride generation atomic fluorescence spectrometry(HG-AFS)method,and distribution proportions of elements in four phases were calculated.This method was based on the reaction of cadmium with 1.5%(m/v)KBH4 solution and 0.5%KOH(m/v)solution to form the hydride gas in medium of 2%(v/v)HCl.The detection limit for cadmium as low as 0.008μg/L was obtained.The lineally correlation coefficient was 0.99992.The relative standard deviation(n=5,C=1.00μg/L)was 3.26%.The proposed method was applied for the determination of cadmium in atmosphere aerosol samples and the recoveries in the range of 95-102.2%were obtained.This method was simple,rapid,less matrix interference and high sensitivity.展开更多
文摘Measurements of atmospheric aerosols and trace gases using the laser radar (lidar) techniques, have been in progress since 1985 at the Indian Institute of Tropical Meteorology, Pune (18°32'N, 73°51'E, 559 m AMSL), India. These observations carried out during nighttime in the lower atmosphere (up to 5.5 km AGL), employing an Argon ion / Helium-Neon lidar provided information on the nature, size, concentration and other characteristics of the constituents present in the tropical atmosphere. The time-height variations in aerosol concentration and associated layer structure exhibit marked differences between the post-sunset and pre-sunrise periods besides their seasonal variation with maximum concentration during pre-monsoon / winter and minimum concentration during monsoon months. These observations also revealed the influence of the terrain of the experimental site and some selected meteorological parameters on the aerosol vertical distributions. The special observations of aerosol vertical profiles obtained in the nighttime atmospheric boundary layer during October 1986 through September 1989 showed that the most probable occurrence of mixing depth lies between 450 and 550 m, and the multiple stably stratified aerosol layers present above the mixing depth with maximum frequency of occurrence at around 750 m. This information on nighttime mixing depth / stable layer derived from lidar aerosol observations showed good agreement with the height of the ground-based shear layer / elevated layer observed by the simultaneously operated sodar at the lidar site.
基金Supported by The Project of Key and Open Laboratory for Cloud Fog Physics Environment of China Meteorological Administration(2009Z0034)The Special Project of Public Welfare Industry(Mete-orology) Science Research of Science and Technology Ministry(GY-HY200806001)Research and Development Projects of Weather Modification Office in Hebei Province:Aircraft Observations Under Fog and Haze Conditions in Hebei Province(10ky04)
文摘By using the probe data of two sorties airplane in the middle and southern parts of Hebei Province in 2007 spring,the characteristics of atmospheric aerosol particles concentration and size distribution in the area in the cloudy day situation were analyzed.The results showed that the overall trend of aerosol particles concentration in the weather systems which included the south branch trough and North China low vortex was the decrease as the height increased.However,if the cirrostratus was in the high altitude,it increased as the height increased.In the bottom of inversion layer,there existed the obvious accumulation of aerosol and cloud droplet.Affected by the complex weather systems,the aerosol particle size distribution presented the multi-peak type for the disturbance of updraft or turbulence.
文摘Atmospheric concentrations of polycyclic aromatic hydrocarbons (PAHs) were measured during various seasons at six different cities/locations in Qingdao alongshore. The annual average PAHs concentration ranged from 16 ng/m3 (at a clean com- pared site) to 308 ng/m3 (in an industry site). The average total particulate PAHs concentration was 74.5 ng/m3 with a higher concentration of particulate PAHs in winter. Based on a year-round dataset, the sources of PAHs in the air of Qingdao were drawn by principal factor analysis and correlation analysis. The results indicated that vehicle emissions and oil burning were the main source of PAHs in Qingdao alongshore.
基金supported by the National Basic Research Program (973) of China (No. 2010CB428505)the National Natural Science Foundation of China (No. 41030962,40875078)+2 种基金the Research Fund for the Doctoral Program of Higher Education of China (No. 20093228110003)the Priority Academic Program Development of Jiangsu Higher Education Institutionsthe Jiangsu Provinc eGraduate Cultivation Innovative Project (No. CXZZ11-0616)
文摘To investigate the impact on urban air pollution by crop residual burning outside Nanjing, aerosol concentration, pollution gas concentration, mass concentration, and water-soluble ion size distribution were observed during one event of November 4-9, 2010. Results show that the size distribution of aerosol concentration is bimodal on pollution days and normal days, with peak values at 60- 70 and 200-300 nm, respectively. Aerosol concentration is 104 cm-3.nm-1 on pollution days. The peak value of spectrum distribution of aerosol concentration on pollution days is 1.5-3.3 times higher than that on a normal day. Crop residual burning has a great impact on the concentration of fine particles. Diurnal variation of aerosol concentration is trimodal on pollution days and normal days, with peak values at 03：00, 09：00 and 19：00 local standard time. The first peak is impacted by meteorological elements, while the second and third peaks are due to human activities, such as rush hour traffic. Crop residual burning has the greatest impact on SO2 concentration, followed by NO2, 03 is hardly affected. The impact of crop residual burning on fine particles （〈 2.1 μm） is larger than on coarse particles （〉 2.1 μm）, thus ion concentration in fine particles is higher than that in coarse particles. Crop residual burning leads to similar increase in all ion components, thus it has a small impact on the water-soluble ions order. Crop residual burning has a strong impact on the size distribution of K^＋, Cl^-, Na^＋, and F- and has a weak impact on the size distributions of NH4^＋, Ca^2＋, NO3^- and SO4^2-.
基金funded by the Special Fund for Public Welfare Industrial(Meteorology)Research of China(Grant No.GYHY20120602104)National Natural Science Foundation of China(Grant Nos.41030962 and 41005089)+1 种基金Jiangsu"333"Program,Jiangsu"Qinglan"program,Graduate Cultivation Innovative Project of Jiangsu province(Grant No.CXZZ110616)the Priority Academic Program Development(PAPD)of Jiangsu Higher Education Institutions
文摘The aerosol number spectrum and gas pollutants were measured and the new particle formation （NPF） events were discussed in Nanjing. The results showed that the size distributions of aerosol number concen- trations exhibited distinct seasonal variations, implying the relations of particle sizes and their sources and sinks. The number concentrations of particles in the nuclei mode （10-30 nm）, Aitken mode （30-100 nm）, accumulation mode （100 -1000 nm） and coarse mode （〉1μm） varied in the order of summer 〉 spring 〉 autumn, summer 〉 autumn 〉 spring, autumn 〉 summer 〉 spring, and spring 〉 autumn 〉summer, re- spectively. The diurnal variation of total aerosol number concentrations showed three peaks in all observed periods, which corresponded to two rush hours and the photochemistry period at noon. In general, the NPF in summer occurred under the conditions of east winds and dominant air masses originating from marine areas with high relative humidity （50%-70%） and strong solar radiations （400 -700 W m-2）. In spring, the NPF were generally accompanied by low relative humidity （14%-30%） and strong solar radiations （400-600 W m-2）. The new particle growth rates （GR） were higher in the summertime in the range of 10- 16 nm h-1. In spring, the GR were 6.8-8.3 nm h-1. Under polluted air conditions, NPF events were seldom captured in autumn in Nanjing. During NPF periods, positive correlations between 10- 30 nm particles and 03 were detected, particularly in spring, indicating that NPF can be attributed to photochemical reactions.
基金This work is financially supported by NKBRSF Project !(G1999043400) Knowledge Creative Project(8-2101 and 82303) founded by
文摘Number concentration and size distribution of atmospheric aerosols were measured in Beijing by an optical particle counter. The relationship between aerosol size distribution and relative humidity is discussed. The results show that the size distribution, diurnal variation, daily variation of atmospheric aerosols have a good relation to relative humidity and Richardson number. Key words Atmospheric aerosol - Number concentration - Size distribution - Relative humidity - Richardson number This work is financially supported by NKBRSF Project (G1999043400), Knowledge Creative Project (8-2101 and 82303) founded by TAP, CAS.The authors would like to express their thanks to Prof. Zhang Wen for his work in this observation.
基金supported by the Ministry of Science and Technology of China (GrantNos. 2006AA06A306 and 2005CB422207) the National Natural Science Foundation of China (Grant Nos.40675082 and 40905055)
文摘Measurements of aerosol physical, chemical and optical parameters were carried out in Guangzhou, China from 1 July to 31 July 2006 during the Pearl River Delta Campaign. The dry aerosol scattering coefficient was measured using an integrating nephelometer and the aerosol scattering coefficient for wet conditions was determined by subtracting the sum of the aerosol absorption coefficient, gas scattering coefficient and gas absorption coefficient from the atmospheric extinction coefficient. Following this, the aerosol hygroscopic growth factor, f（RH）, was calculated as the ratio of wet and dry aerosol scattering coefficients. Measurements of size-resolved chemical composition, relative humidity （RH）, and published functional relationships between particle chemical composition and water uptake were likewise used to find the aerosol scattering coe？cients in wet and dry conditions using Mie theory for internally- or externally-mixed particle species [（NH_4）_2SO_4, NH_4NO_3, NaCl, POM, EC and residue]. Closure was obtained by comparing the measured f（RH） values from the nephelometer and other in situ optical instruments with those computed from chemical composition and thermodynamics. Results show that the model can represent the observed f（RH） and is appropriate for use as a component in other higher-order models.
基金supported by the National Natural Science Foundation of China(Nos.41175111 and 21177078)the Strategic Pilot Science and Technology Project of the Chinese Academy of Sciences(Class B)(No.XDB05010200)+1 种基金the National Natural Science Foundation of China(No.41265008)Key Discipline Construction Project,Guizhou(No.ZDXK[2016]11)
文摘Size–fractioned atmospheric aerosol particles were collected during a typical heavy air pollution event in Beijing. The organic and inorganic components on the surfaces of the samples were analyzed using time–of–flight secondary ion mass spectrometry（TOF–SIMS）.The variation characteristics of the surface chemical composition and influencing factors were studied, and the possible sources of these chemical compositions were identified through principal component analysis. The results showed that inorganic components such as crustal elements and sulfate, and organic components such as aliphatic hydrocarbons and oxygen–containing organic groups were present. Some surface components, such as polycyclic aromatic hydrocarbons, heavy metals and fluorides may exert adverse effects on human health. The species and relative percentages of the chemical components varied with particle size, diurnal and pollution progress. During a heavy pollution event, the species and relative percentages of secondary components such as oxygen–containing organic groups and sulfurous compounds increased, indicating that particles aged during this event. The surface chemical composition of the aerosol particles was affected mainly by emissions from coal combustion and motor vehicles. In addition, air pollution, meteorological factors, and air mass transport also exerted a significant effect on the surface chemical composition of aerosol particles.
基金supported by the following projects:the National Key R&D(Research and Development)Program of China(No.2016YFC0202800:Task 1)the National Natural Science Foundation of China(Nos.41475127,41571130021)the framework research program on ‘Photochemical smog in China’ financed by the Swedish Research Council(No.639-2013-6917)
文摘Particle density is an important physical property of atmospheric particles. The information on high time-resolution size-resolved particle density is essential for understanding the atmospheric physical and chemical aging processes of aerosols particles. In the present study, a centrifugal particle mass analyzer （CPMA） combined with a differential mobility analyzer （DMA） was deployed to determine the size-resolved effective density of 50 to 350 nm particles at a rural site of Beijing during summer 2016. The measured particle effective densities decreased with increasing particle sizes and ranged from 1.43 to 1.55 g/cm3, on average. The effective particle density distributions were dominated by a mode peaked at around 1.5 g/cm3 for 50 to 350 nm particles. Extra modes with peaks at 1.0, 0.8, and 0.6 g/cm3 for 150, 240, and 350 nm particles, which might be freshly emitted soot particles, were observed during intensive primary emissions episodes. The particle effective densities showed a diurnal variation pattern, with higher values during daytime. A case study showed that the effective density of Aitken mode particles during the new particle formation （NPF） event decreased considerably, indicating the significant contribution of organics to new particle growth.
基金supported by the Project of National Natural Science Foundation of China (Nos.41175111,20677054,21177078)the Strategic Pilot Science and Technology Project of the Chinese Academy of Sciences (Class B) (No.XDB05010200)
文摘Atmospheric aerosol particle samples were collected using an Ambient Eight Stage（Non-Viable） Cascade Impactor Sampler in a typical urban area of Beijing from 27 th Sep.to 5th Oct.,2009.The surface chemistry of these aerosol particles was analyzed using Static Time of Flight-Secondary Ion Mass Spectrometry（Static TOF-SIMS）.The factors influencing surface compositions were evaluated in conjunction with the air pollution levels,meteorological factors,and air mass transport for the sampling period.The results show that a variety of organic ion groups and inorganic ions/ion groups were accumulated on the surfaces of aerosol particles in urban areas of Beijing;and hydrophobic organic compounds with short-or middle-chain alkyl as well as hydrophilic secondary inorganic compounds were observed.All these compounds have the potential to affect the atmospheric behavior of urban aerosol particles.PM1.1–2.1and PM3.3–4.7had similar elements on their surfaces,but some molecules and ionic groups demonstrated differences in Time of Flight-Secondary Ion Mass Spectrometry spectra.This suggests that the quantities of elements varied between PM1.1–2.1and PM3.3–4.7.In particular,more intense research efforts into fluoride pollution are required,because the fluorides on aerosol surfaces have the potential to harm human health.The levels of air pollution had the most significant influence on the surface compositions of aerosol particles in our study.Hence,heavier air pollution was associated with more complex surface compositions on aerosol particles.In addition,wind,rainfall,and air masses from the south also greatly influenced the surface compositions of these urban aerosol particles.
基金supported by the Natural Science Foundation of China (No.41975156)。
文摘Amino acids(AAs)including D-and L-enantiomers are a group of organic nitrogen species in ambient aerosol.Due to the low abundances of AAs(level of ng/m^(3))and the matrix effects by coexistent components,it is challenging to quantify AA enantiomers in ambient aerosols especially under pollution conditions.In this study,we present an optimized method for analyzing AA enantiomers in atmospheric aerosol samples including a pretreatment process and the detection by high performance liquid chromatography coupled to a fuorescence detector(HPLC-FLD).Matrix effects caused by coexistent chemicals on AA enantiomers analysis in ambient aerosol samples were investigated especially for those collected in pollution episodes.The results revealed that the determination of AA enantiomers is significantly affected by the coexistent organic carbon(as a proxy of organic matter)and water-soluble ion of NH_(4)^(+).To remove the matrix effects,we applied a pretreatment using the solid phase extraction column coupled with alkaline adjustment to sample extract.After pretreatment,18 AAs including 6 pairs of D-and L-enantiomers(i.e.,leucine,isoleucine,valine,alanine,serine,and aspartic acid)can be successfully separated and quantified in aerosol samples by HPLC-FLD.The recoveries are in the range of 67%-106%.This method was successfully applied to the urban aerosol samples from pollution and non-pollution periods for AA enantiomers determination.We suggest that the concentrations of D-AAs and the ratio of D-AA/L-AA are indicative of the contribution of bacterial sources and the infuence of biomass burning.
文摘The chemical composition of atmospheric aerosols has been investigated. Contributions ofsulfate and soot in aerosols to the atmospheric extinction are studied. Discussions are made on the problems of aerosol emitted from volcano, forest fires in northern China, 1987 and oil field fires in Kuwait, 1991. It is indicated that the changes in concentration, particle size, and chemical composition of aerosol after those events could have impacts on the climate change either regionally or globally and that the impact of aerosol particles on climate change could compensate for some temperature increase caused by greenhouse gases and the increase of surface intensity of ultraviolet radiation due to ozone layer depletion.
文摘Solar ultraviolet radiation reaching the ground can be reduced due to light scattering of atmospheric aerosols. Aerosol pollution has led to the decrease in biological active UV-B radiation by about 45% and 10% in city and rural areas, respectively. In populated areas, effect of aerosol scattering on UV-B radiation may offset the increased amount of UV-B caused by ozone depletion, but in clean areas such as two poles, ozone depletion may have great damage effects on ecosystems.
基金National Key R&D Program of China(2019YFC0214605)Key-Area R&D Program of Guangdong Province (2020B1111360003)+4 种基金Provincial Natural Science Foundation of Guangdong (2021A1515011494)Science and Technology Innovation Team Plan of Guangdong Meteorological Bureau (GRMCTD202003)Open Project of the Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration,Nanjing University of Information Science and Technology (KDW 1803)Scientific and Technological Innovation Team Project of Guangzhou Joint Research Center of Atmospheric Sciences,China Meteorological Administration (201704)Science and Technology Research Project of Guangdong Meteorological Bureau (GRMC2018M01)。
文摘The environmental impact of aerosols is currently a hot issue that has received worldwide attention. Lacking simultaneous observations of aerosols and carbon flux, the understanding of the aerosol radiative effect of urban agglomeration on the net ecosystem carbon exchange(NEE) is restricted. In 2009-2010, an observation of the aerosol optical property and CO_(2) flux was carried out at the Dongguan Meteorological Bureau Station(DMBS) using a sun photometer and eddy covariance systems. The different components of photosynthetically active radiation(PAR),including global PAR(GPAR), direct PAR(DPAR), and scattered PAR(FPAR), were calculated using the Santa Barbara DISORT Atmospheric Radiative Transfer(SBDART) model. The effects of PAR on the NEE between land-atmosphere systems were investigated. The results demonstrated that during the study period the aerosol optical depth(AOD)reduced the DPAR by 519.28±232.89 μmol photons · m^(-2)s^(-1), but increased the FPAR by 324.93±169.85μmol photons ·m^(-2)s^(-1),ultimately leading to 194.34±92.62 μmol photons · m^(-2)s^(-1);decrease in the GPAR. All the PARs(including GPAR,DPAR, and FPAR) resulted in increases in the NEE(improved carbon absorption), but the FPAR has the strongest effect with the light use efficiency(LUE) being 1.12 times the values for the DPAR. The absorption of DPAR by the vegetation exhibited photo-inhibition in the radiation intensity > 600 photons · m^(-2)s^(-1);in contrast, the absorptions of FPAR did not exhibit apparent photo-inhibition. Compared with the FPAR caused by aerosols, the DPAR was not the primary factor affecting the NEE. On the contrary, the increase in AOD significantly increased the FPAR, enhancing the LUE of vegetation ecosystems and finally promoting the photosynthetic CO_(2) absorption.
基金supported by the Science and Technology Major Project of Natural Science Foundation of Inner Mongolia,China(No.21800-5173909)the Science and Technology Major Project on Air Pollution Prevention and Prediction in Hohhot-Baotou-Ordos Cities Group of Inner Mongolia(No.2020ZD0013)+1 种基金the Young Scientific&Technological Leading Talent Program of Inner Mongolia(No.NJYT2022092)the Science Fund for Distinguished Young Scholars of Inner Mongolia(No.2019JQ05)。
文摘As a vital type of light-absorbing aerosol,brown carbon(BrC)presents inherent associations with atmospheric photochemistry and climate change.However,the understanding of the chemical and optical properties of BrC is limited,especially in some resource-dependent cities with long heating periods in northwest China.This study showed that the annual average abundances of Water-soluble BrC(WS-BrC)were 9.33±7.42 and 8.69±6.29μg/m^(3)in Baotou and Wuhai and the concentrations,absorption coefficient(Abs_(365)),and mass absorption efficiency(MAE365)of WS-BrC presented significant seasonal patterns,with high values in the heating season and low values in the non-heating season;while showing opposite seasonal trends for the Absorption Angstr?m exponent(AAE_(300-400)).Comparatively,the levels of WS-BrC in developing regions(such as cities in Asia)were higher than those in developed regions(such as cities in Europe and Australia),indicating the significant differences in energy consumption in these regions.By combining fluorescence excitation-emission matrix(EEM)spectra with the parallel factor(PARAFAC)model,humic-like(C1 and C2)and proteinlike(C3)substances were identified,and accounted for 61.40%±4.66%and 38.6%±3.78%at Baotou,and 60.33%±6.29%and 39.67%±4.17%at Wuhai,respectively.The results of source apportionment suggested that the potential source regions of WS-BrC varied in heating vs.non-heating seasons and that the properties of WS-BrC significantly depended on primary emissions(e.g.,combustion emissions)and secondary formation.
文摘Based on observing data of atmospheric aerosol in the north suburban area of Nanjing from September to November in 2007, the number concentration, mass concentration, size distribution and optical properties of atmospheric aerosol particles and the relation to meteorological factors were analyzed, and their concentration and optical properties during hazy and non-hazy days were compared. The results showed that aerosol pollution was serious in autumn in this region; the deterioration of visibility had close correlation to fine particles, that is, the average number concen- tration of aerosol was 17 044.2 cm^-3, in which ultra fine particles accounted for 64.3%; the daily average mass concentration of PM2.5 was 281 μg/m3, and the ratio of PM2.5 to PM10 was 0.74; the accumulation mode particles dominated in number and surface concentration distributions, while the volume concentration distribution presented a main peak at size of 1.0 -2.8 μm; fine particles increased during hazy days compared with non-hazy days; the scatter coefficient closely correlated to the particle size, concentration and atmospheric humidity. It was also indicated that meteorological conditions played a critical role in formation of hazy weather, that is, weak large-scale weather systems, low wind speed, high humidity and strong inversion were favorable conditions for hazy weather in autumn.
文摘Dear Colleagues, We would like to invite you to submit manuscripts to a special issue entitled ＂Current Research on Atmospheric Aerosols and Trace Gases over the Polar Regions＂ of the Journal Advances in Polar Science （APS）. APS is an international, peer-reviewed journal jointly sponsored by the Polar Research Institute of China （PRIC） and the Chinese Arctic and Antarctic Administration （CAA）. It is a quarterly journal published in March, June, September and December by Science Press of China and circulated internationally （ISSN 1674-9928, CN 31-2050/P）. Articles published in APS are free of charge with generous funding from PRIC. For more details, please visit the APS＇s websites. Thank you in advance for your consideration to submit manuscripts to this special issue, and we encourage you to share this announcement broadly with interested colleagues.
基金Sponsored by the Science and Technology Project of Beijing Municipal Administration Center of Parks(ZX2019)Beijing Science and Technology Plan Project(D171100001817001)
文摘Taking the Phyllostachys heterocycla forest in Qishan National Forest Park of Fuzhou for example, this study observed the diurnal variation of atmospheric aerosol particles in the forest in the growing season.The results showed that:(1) The diurnal variation curves of the particle concentration of the forest and the forest edge had "two peaks and two troughs", but the peaks and troughs of the forest edge were advanced or delayed.The concentrations of the particles in the forest and at the forest edge had two peaks at 11:00–13:00 and 17:00–19:00 and two troughs at 7:00–9:00 and 15:00–17:00.(2) For the forest and the forest edge, the diurnal variation trends of the particles of different particle sizes were generally similar, except that the peaks and troughs of fine particles were slightly earlier or lagging than that of coarse particles.(3) The concentrations of the particles were positively correlated with temperature, humidity and light, and negatively correlated with wind speed, and the concentrations of the particles at the forest edge were significantly negatively correlated with wind speed.
基金supported by a grant from the National Natural Science Foundation of China(Nos.11490551)
文摘In recent years,haze has posed a serious threat to the global climate change,ecological balance and human health.In this study,the laboratory experiments and field observations were performed and a possible charging mechanism was proposed to investigate the space charge properties in haze events.The laboratory experiments showed that the charge polarity of primary aerosol is determined by species of combustion fuels while the magnitude is dependent on the combustion completeness.The field observations revealed that the space charge of atmosphere aerosol in haze events differs from that of fair weather and is closely related to PM2.5 concentration when Relative Humidity(RH)<60%,with 1 to 2 orders of magnitude less than the case when RH≥60%.The analysis of equivalent chargeto-mass ratio(ECTM)suggested that in haze events the space charge is governed by primary aerosol emitted by combustion of fossil fuel in a low relative humidity,whereas it is manipulated by the secondary chemical reaction of atmosphere aerosol in a high relative humidity.And we can identify the main pollutants in haze events according to the polarity of atmosphere aerosol and quickly take measures when RH<60%.Accordingly,the dusthaze of RH<80% can be divided into dry-dust-haze when RH<60%and wet-dust-haze when 60%≤RH<80%.Our study firstly elucidated the space charge properties of atmosphere aerosol in haze events and can provide a new perspective for the prevention and control of air pollution.
文摘In this paper,two different diameter particles(TSP,PM10)were collected by TH-16A four-channels classification air sampler.The samples were treated by HNO3.Analysis of cadmium was carried out by hydride generation atomic fluorescence spectrometry(HG-AFS)method,and distribution proportions of elements in four phases were calculated.This method was based on the reaction of cadmium with 1.5%(m/v)KBH4 solution and 0.5%KOH(m/v)solution to form the hydride gas in medium of 2%(v/v)HCl.The detection limit for cadmium as low as 0.008μg/L was obtained.The lineally correlation coefficient was 0.99992.The relative standard deviation(n=5,C=1.00μg/L)was 3.26%.The proposed method was applied for the determination of cadmium in atmosphere aerosol samples and the recoveries in the range of 95-102.2%were obtained.This method was simple,rapid,less matrix interference and high sensitivity.
