Study Of Atmospheric Aerosols Research Articles

Long‐term atmospheric aerosol study at urban and rural sites in Belgium using multi‐elemental analysis by particle‐induced x‐ray emission spectrometry and short‐irradiation instrumental neutron activation analysis

Long‐term atmospheric aerosol study at urban and rural sites in Belgium using multi‐elemental analysis by particle‐induced x‐ray emission spectrometry and short‐irradiation instrumental neutron activation analysis

Long-term atmospheric aerosol study at urban and rural sites in Belgium using multi-elemental analysis by particle-induced x-ray emission spectrometry and short-irradiation instrumental neutron activation analysis

The Ghent PM10 stacked filter unit (SFU) sampler was used to collect size-fractionated atmospheric aerosol samples, first at an urban residential site in Ghent, Belgium, and subsequently at a rural site (Waasmunster, about half way between the cities of Ghent and Antwerp). The samplings at Ghent took place in 1993–94 (over a 14 month period) and a total of 118 daily SFU samples were collected. At Waasmunster, 142 daily SFU samples were taken in 1994–95 (over a 16 month period). All samples were analyzed for the particulate mass, black carbon, and up to 29 elements. The elements were measured by particle-induced x-ray emission spectrometry (PIXE) and short-irradiation instrumental neutron activation analysis (INAA). The data for common elements measured by both techniques were compared. This permitted an assessment of the magnitude of the particle size effect for the lighter elements in PIXE. The data sets were subjected to receptor modeling with absolute principal component analysis, and relationships between the intensities of the components (i.e. the component scores) and various meteorological variables were examined. The anthropogenic and crustal components were consistently negatively correlated with wind speed. Overall, the aerosol concentrations, compositions, sources and source contributions to the particulate mass were remarkably similar for the urban and rural sites. © 1998 John Wiley & Sons, Ltd.

A study of atmospheric aerosols from five sites in Mexico city using PIXE

Atmospheric aerosol samples collected in five sites in the Metropolitan Area of Mexico City were analyzed with proton induced X-ray emission (PIXE). Stacked Filter Units (SFU) of the Davis design were employed to obtain samples of fine aerosols (smaller than 2.5 μm Mean Aerodynamic Diameter) on polycarbonate filters. The study was conducted during the first half of 1996 (16 weeks, from 31st January to 6th June), exposing the filters once a week, from 8:00 to 14:00 h. PIXE analyses of the filters using a 2 MeV proton beam produced by the Instituto de Física, UNAM, 5.5 MV Van de Graaff accelerator were compared with those carried out using a 2.2 MeV proton beam from the 56 cm isochronous cyclotron at the Universidad de Chile, showing a good correlation between both laboratories. Analysis of variance of the measured elemental concentrations showed differences in the mean concentrations for several elements at the sampling sites. Comparisons with other studies are also given.

ESTIMATING THE LUNG DEPOSITION OF PARTICULATE POLYCYCLIC AROMATIC HYDROCARBONS ASSOCIATED WITH MULTIMODAL URBAN AEROSOLS

Recent epidemiological evidence of associations between increased mortality and ambient particle concentrations suggests that ultrafine particles (smaller than 1 mum diameter) and their constituents are potentially significant contributors because of their enhanced toxicity and their potential for greater lung penetration. Measurements of size distributions of potentially carcinogenic polycyclic aromatic hydrocarbons (PAH) in urban aerosols show their predominance in ultrafine and fine modes centered about 70 and 700 nm. In this article we present estimates of the regional lung deposition of PAH associated with a typical multimodal urban aerosol and examine the effect of varying size distribution characteristics on lung deposition. Size-dependent deposition fractions, from a deterministic calculation using deposition probabilities in a lung anatomical model, have been combined with the fraction of aerosol or PAH mass present in each particle size range and integrated over the entire size range to obtain the fraction of pollutant mass deposited in each lung region and the total lung. For typical urban aerosols the fraction of aerosol mass deposited ranges from 0.48 to 0.56 in the total lung, with 0.20 to 0.26 in the pulmonary lung and 0.28 to 0.30 in the tracheobronchial lung. For associated PAH the fractional mass deposited ranges from 0.27 to 0.32 in the total lung, with a large fraction (0.23-0.28) in the pulmonary lung and 0.04 to 0.05 in the tracheobronchial lung. The fraction deposited is relatively invariant with varying size distribution characteristics like mass median diameter and mass fraction in each mode, making it possible to generalize the results to most locations. Exposure in a polluted urban air basin like the Los Angeles basin, with average PM-10 concentrations from 47 to 87 mug m-3 and particulate PAH concentrations from 0.1 to 3 ng m-3, would result in average daily exposures to PM-10 and PAH, respectively, of 402 mug h m-3 and of 9.0 ng h m-3. Resulting average daily doses, calculated from the lung deposition estimates, are 294 mug day-1 and 3.3 ng day-1, respectively, of aerosol and PAH mass deposited in the total lung with 142 mug day-1 and 2.9 ng day-1, respectively, in the pulmonary lung and compare with doses from sidestream environmental tobacco smoke (ETS) exposure in smoking areas. While it is difficult to interpret the toxicological implications of this dose, these calculations indicate high pulmonary deposition and the risk of delivery of carcinogenic PAH in ambient aerosols directly to the lung interstitium. This reiterates the need for detailed study of ultrafine atmospheric aerosols and their toxic constituents in various microenvironments in which population exposures occur.

A chamber for laboratory studies of atmospheric aerosols and clouds

A stainless-steel chamber has been constructed and interfaced to a Fourier transform infrared spectrometer for the purpose of studying laboratory simulated atmospheric aerosols and clouds. The chamber is cylindrical in design and is comprised of a double-walled inner assembly that resides within an outer vacuum jacket. The volume of the aerosol sample region is 28 L. By circulating refrigerated methanol between the double walls of the inner assembly, constant temperature control of the sample region can be maintained between 187 and 300 K. A study of temperature uniformity within the chamber at 291, 240, and 187 K revealed a standard deviation in temperature of 1.6 K as determined from measurements made using five copper–constantan thermocouples. Good agreement is obtained between thermocouple measured temperatures and rotational temperatures computed from infrared absorption spectra of methane gas. The chamber described here has been used to examine heterogeneous chemistry of solid powder samples. A technique of generating an aerosol sample by rapidly dispersing a solid powder in a gas is presented. The half-life of a γ-alumina aerosol sample was measured to be 25 min.

PIXE study of atmospheric aerosols in mountain region of Poland

Proton Induced X-ray Emission (PIXE) method has been used to study the composition and possible origin of atmospheric aerosols in the mountain region of Poland. The filters were collected during two periods of one week in summer and in winter in the mountain observatory at 1985 m a.s.l. and in Zakopane, a town situated at the foot of the mountains. The most important contributions to the atmospheric pollution were determined. The comparison of the results obtained at both locations allowed the separation of aerosols into two groups: those due to the local and to the long range pollution.

The use of PIXE and complementary ion beam analytical techniques for studies of atmospheric aerosols

PIXE is nowadays a routine analytical technique in the study of atmospheric aerosols. If it aspires to continue to be so in the future, it will have to compete with a range of other powerful analytical techniques, and outperform them in some respect. It will be shown how PIXE can indeed play an important role in future studies of atmospheric aerosols. For clarification, two concrete examples will be discussed in some detail, involving PIXE either as the sole analytical technique or used in combination with various other ion beam analytical techniques for an almost complete characterisation of the atmospheric aerosol.

Studies of atmospheric aerosols in large urban areas using PIXE: an overview

The uncontrolled growth of some cities around the world has produced an increasing concentration of atmospheric aerosols. They have effects on the air quality in those geographical areas, affecting public health, visibility, and buildings. A better knowledge of the aerosol characteristics is required. A comparison of the sources, sampling procedures, analytical use of particle induced X-ray emission (PIXE), and composition of atmospheric aerosols in several urban areas around the world, having more than four million inhabitants, is presented. The need for standard procedures and analysis, as well as the use of other techniques in addition to PIXE, is pointed out. It is shown how local sources (traffic, industry, soil), geographical characteristics, or external sources, influence the aerosol composition.

Gypsum and Other Calcium-Rich Aerosol Particles above the North Sea

Ca-containing particles, especially CaSO4 particles, have been encountered in several atmospheric aerosol studies. An overview is given of the different sources of airborne Ca-containing particles. The North Sea atmosphere is studied to identify the different Ca-containing particle types and to find the correlation between their occurrence and the source regions of the corresponding air masses. About 50 000 individual aerosol samples were collected above the Southern Bight of the North Sea for several wind directions and analyzed for their composition using electron probe X-ray microanalysis. Nonhierarchical cluster analysis is performed on the data to reveal the different particle types, their relative abundances and their sources. CaSO4 in most cases constitutes the largest fraction of the Ca-containing particles. Extremely high numbers of CaSO4 particles are found for northeastern winds, coming from the central part of Germany, suggesting that a great fraction is derived from anthropogenic sources loca...

“Global Change” related and other atmospheric aerosol research at the university of Gent, and the role of PIXE therein

The PIXE technique plays an essential role in the “Global Change” related and regional atmospheric aerosol studies that are being conducted at the University of Gent. It is the only analytical technique used for detailed examinations of elemental mass size distributions in Greenland and the Norwegian Arctic, which aim at improving our understanding of the transfer of particulate species from air to snow. PIXE also provides concentration data for key elements in multi-sample, multi-species stacked filter unit data sets that are examined by receptor modeling techniques in order to identify the contributing aerosol types, to apportion the particulate mass and the various aerosol constituents to these aerosol types, and to determine the extent of the anthropogenic perturbation. Results are presented from such work in equatorial/tropical regions, where the emphasis is placed on assessing the impact of biomass buring on the climatically important fine aerosol. PIXE is also extensively used in aerosol studies around and above the North Sea. Results are presented from a Lagrangian transport experiment that aimed at examining the changes in concentrations and characteristics of gaseous and particulate species in air masses as they move over the North Sea. Finally, preliminary results are presented from long-term aerosol collections in southern Norway.

Long-Term Variation (1970-1994) of Atmospheric Aerosol in Kitakyushu City.

A long-term (1970-1994) study of atmospheric aerosol has been conducted in Kitakyushu City. The annual mean concentrations of aerosol had gradually decreased until 1983 and they have been stable since then. To investigate the change of the aerosol quality, the total mass and constituents of aerosols collected for 1972-1974 (period I : heavily polluted period) and 1984-1988 (period II : improved period) were compared. The decrease rate (%) of all constituents (inorganic ions : SO42-, NO3-, F-, Cl-, Ca2+ and Mg2+ ; metals : Fe, Mn, Zn, V and Pb) except SO42- was much larger than that of the aerosol amount. The concentration of NO3- in the aerosol in period II was 54% of that in period I. It was considered that this result was based on the decrease (period II/period I : 45%) of atmospheric NOx, which was supposed to be a precursor. In contrast, there was a nonproportional relationship between the decrease (88%) of SO42- in the aerosol and the decrease (20%) of atmospheric SO2. These results show the characteristic of the change of aerozol in Kitakyushu City for 24 years (1970-1994).

Atlantic atmospheric aerosol studies: 2. Compendium of airborne backscatter measurements at 10.6μm

The airborne backscatter measurements at 10.6 μm, from the South Atlantic Backscatter Lidar Experiment (SABLE) and the Global Atmospheric Backscatter Lidar Experiment (GABLE) programs over the Atlantic, are gathered together and presented. Plots of backscatter versus altitude are shown for 80 flight sequences. These data comprising about 4×105 measurements from over 180 flight hours is statistically analyzed. The material is distributed in altitude (1 km) and backscatter (half decade) intervals and presented in tabular and histogram form for six principal regions and seasons: South Atlantic summer, South Atlantic winter, far‐North Atlantic spring, mid‐Atlantic spring/summer, and Northeast Atlantic winter and summer. Several features of the results are discussed, including the incidence of low backscatter and drop‐outs and the remarkably high incidence of thin cirrus in the southern tropical winter season. The compendium should provide a climatology of atmospheric backscatter at 10.6 μm for regions of the Atlantic during the relatively clean atmospheric period 1988–1990.

Contribution to the atmospheric aerosol study in the parisian metropolitan area: Particle quantitative and qualitative study

Contribution to the atmospheric aerosol study in the parisian metropolitan area: Particle quantitative and qualitative study

Atmospheric aerosols in Lombardy

The paper deals with the study of atmospheric aerosols in some sites in Lombardy. Measurement campaigns and sampling methods are reported along with the data obtained with XRF and PIXE techniques on the aerosol mass concentration and its elemental composition.

PARTICLE CHARACTERIZATION AT RURAL, SUBURBAN AND URBAN AEROSOL SAMPLING SITES IN HUNGARY

The study of atmospheric aerosols originating from natural and anthropogenic processes is of basic importance for a detailed understanding of the physics and chemistry of the atmosphere. Particle Induced X-ray Emission (PIXE) technique has been used by the authors for studying regularly the elemental composition of rural, suburban, and urban aerosols collected at six sampling sites in Hungary. Observed data presented in terms of concentrations and regional signature values and evaluated wind sector partition and in transport modelling revealed the natural/anthropogenic contribution to the moderate air pollution here. Dry deposition velocities have been deduced for elements V, Cr, Mn, Co, Ni, Cu, Zn, Cd, and Pb. Model calculations based on annual emission data and observed elemental concentrations resulted in total dry and wet deposition masses of the above elements to the territory of the country. At the same time, deduced budget data for the emission and deposition of the constituents indicated whether the country represents a net source or a sink for the above mentioned elements in the regional aerosol transport between neighbouring countries. Evidences have been found for intrusion events of Saharan aerosol to the atmosphere of Hungary. Part of the data collected recently will be evaluated in the frame-work of an international co-ordinated research programme.

Sampling and measurement conditions for PIXE analysis of atmospheric aerosols

The PIXE technique has long been applied to the study of atmospheric aerosols and it continues as one of the most important areas of application. In this paper, sampling techniques for atmospheric aerosols designed for PIXE analysis are addressed and the optimum measurement conditions for PIXE analysis is investigated. Based on these studies, we have selected a stacked filter sampling system as our standard sampling method for atmospheric aerosols and double measurements by two different analytical conditions as the standard measurement condition of PIXE analysis.

Atmospheric aerosol studies in southern Norway using size-fractonating smapling devices and nuclear analytical techniques

Atmospheric aerosol samples were collected during spring sampling campaigns in 1988 and 1989 at Birkenes and Nordmoen in southern Norway. The aerosol collectors used included stacked filter units (SFUs), a low volume sampler (referred to as ILVS), which consists of a filter preceded by three impaction stages, and an 11-stage Berner low-pressure impactor (LPI). All samples were analyzed for up to about 40 elements by INAA and PIXE. The resuls obtained from parallel samplings were intercompared in terms of ratios ILVS/SFU and LPI/SFU, whereby these ratios were calculated separately for the coarse and fine size fractions. For the ILVS/SFU parallel samplings, excellent agreement was observed between the results for the fine fraction, with the overall mean average ratio (based on 21 samples and 22 elements) being 0.99±0.10. For the coarse fraction, the overall mean ILVS/SFU ratio (based on 21 elements) was 0.75±0.13. This low result is explained by different upper-particle-size cut-offs of the two samplers. For the parallel samplings with LPI and SFU, the agreement was poorer, but still reasonable. The atmospheric concentrations observed at the two sites in the two campaigns and also the LPI size distributions for the various elements are discussed briefly.

Model study of atmospheric aerosols in some typical places of China

Since 1983 the imaginary parts of refractive index, elemental concentrations and size distributions ofatmospheric aerosols have been measured in some typical regions of China, including Tianjin, Shenyang, Nanjing, Hefei and Shengzheng cites, Fucun village, Bright Peak in Huangshan mountain (1840 m ASL), Yangbajin in Tibet (4300m ASL), South China Sea and coast. A large amount of data sets has been obtained and provides a better understanding of the characteristics of the aerosols. Based on these results, the China Atmospheric Aerosol Model has been developed.

Deuteron excitation as an alternative in PIXE analysis

In comparison with protons deuterons show several advantageous features when used to induce X-ray emission for elemental analysis, such as lower bremsstrahlung radiation, higher penetration range and reduction of the charge collected in the target. On the other hand, a high background due to scattering on the chamber material was observed. Beam loss ratios in samples of different thicknesses are presented for deuterons of 4.2 MeV and for the equivalent protons of 2.1 MeV. An extensive study of atmospheric aerosols using 4.2 MeV deuterons is described.

Elemental composition study of atmospheric aerosols by the X-ray-fluorescence method using synchrotron radiation

The paper presents results of the elemental composition study of coarse and fine fractions of atmospheric aerosols by X-ray-fluorescence using synchrotron radiation, the excitation energy being 31 keV. The detection limits of the elements determined are at a level of 10 ng cm −2.