Urban Aerosol Characteristics: General Discussion

Talanta, 2011

A method developed for analyzes of large number of aerosol samples using Energy Dispersive X-Ray Fluorescence (EDXRF) and its performance were discussed in this manuscript. Atmospheric aerosol samples evaluated in this study were collected on cellulose fiber (Whatman-41) filters, employing a Hi-Vol sampler, at a monitoring station located on the Mediterranean coast of Turkey, between 1993 and 2001. Approximately 1700 samples were collected in this period. Six-hundred of these samples were analyzed by instrumental neutron activation (INAA), and the rest were archived. EDXRF was selected as an analytical technique to analyze 1700 aerosol samples because of its speed and non-destructive nature. However, analysis of aerosol samples collected on fiber filters with a surface technique such as EDXRF was a challenge. Penetration depth calculation performed in this study revealed that EDXRF can obtain information from top 150μm of our fiber filter material. Calibration of the instrument with...

Journal of Environmental Monitoring, 2007

This paper concludes a five year program on research into the use of a portable X ray fluorescence (XRF) analyzer for analyzing lead in air sampling filters from different industrial environments, including mining, manufacturing and recycling. The results from four of these environments have already been reported. The results from two additional metal processes are presented here. At both of these sites, lead was a minor component of the total airborne metals and interferences from other elements were minimal. Nevertheless, only results from the three sites where lead was the most abundant metal were used in the overall calculation of method accuracy. The XRF analyzer was used to interrogate the filters, which were then subjected to acid digestion and analysis by inductively coupled plasma optical emission spectroscopy (ICP OES). The filter samples were collected using different filter holders or ''samplers'' where the size (diameter), depth and homogeneity of aerosol deposit varied from sampler to sampler. The aerosol collection efficiencies of the samplers were expected to differ, especially for larger particles. The distribution of particles once having entered the sampler was also expected to differ between samplers. Samplers were paired to allow the between sampler variability to be addressed, and, in some cases, internal sampler wall deposits were evaluated and compared to the filter catch. It was found, rather surprisingly, that analysis of the filter deposits (by ICP OES) of all the samplers gave equivalent results. It was also found that deposits on some of the sampler walls, which in some protocols are considered part of the sample, could be significant in comparison to the filter deposit. If it is concluded that wall deposits should be analyzed, then XRF analysis of the filter can only give a minimum estimate of the concentration. Techniques for the statistical analysis of field data were also developed as part of this program and have been reported elsewhere. The results, based on data from the three workplaces where lead was the major element present in the samples, are summarized here. A limit of detection and a limit of quantitation are provided. Analysis of some samples using a second analyzer with a different X ray source technology indicated reasonable agreement for some metals (but this was not evaluated for lead). Provided it is only necessary to analyze the filters, most personal samplers will provide acceptable results when used with portable XRF analysis for lead around applicable limit values.

Journal of Aerosol Science, 2018

This work reports on qualitative and semi-quantitative elemental analysis of particulate matter (PM) collected on PTFE membrane filters, for a source apportionment study conducted in Brescia (Italy). Sampling was undertaken in a residential area where an increase in Mn emissions has been highlighted by previous studies. Filters are measured by means of X-ray Fluorescence (XRF) based techniques such as micro-XRF and grazing incidence XRF using synchrotron radiation, Mo or W excitation sources, after applying an automatized sample preparation method. A heterogeneous distribution in PM shape, size and composition was observed, with features typical of anthropogenic sources. XRF measurements performed at various incidence angle, on large areas and different experimental setup were reproducible. The results demonstrate a successful comparison of the various XRF instrumentation, and the decrease in Mn content with the distance away from the identified emission source. This work highlights the potentialities of the presented approach to provide a full quantitative analysis, and ascertain its suitability for providing a direct, fast, simple and sensitive elemental analysis of filters in source apportionment studies and screening purposes.

A fast and reliable method for the analysis of airborne loaded filters becomes more and more important for monitoring campaigns and inventory studies at sites with airborne pollution. X- ray fluorescence spectroscopy (XRF) can perform quantitative analysis on filters without any pretreatment. Quantitative determination of various metals on loaded filters requires the use of calibration curves set up with synthetic filters. For accurate analysis, the calibration standards have to be prepared with a comparable matrix composition as the real filter samples. Therefore, cellulose nitrate filters were loaded by means of aerosol generation with various metals. The performance of an optimized aerosol generation system, based on the ultrasonic nebulization of a multi-element solution, is presented in this work. A multi-element solution is converted into a fine dense aerosol by ultrasonic action. The produced aerosol is dried and collected onto a filter. Filters can be loaded sequentially wit...

Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2003

Instrumental neutron activation analysis (INAA) and particle induced X-ray emission (PIXE) are commonly used to yield multielemental data in atmospheric studies. In this work the quality assurance of the analytical data is discussed based on two studies. The first is a precision study, involving sampling and analysis of air particulate matter in the size ranges of the aerodynamic diameter (AD) <2.5 lm and 2.5 lm < AD < 10 lm, using two Gent collectors, operating sideby-side, on a daily basis. Mass concentrations obtained by gravimetry, for the two collectors, were compared showing a very good reproducibility. Elemental analysis was carried out in different parts of the same filter, testing both the homogeneity of the aerosol sample and the precision of the techniques. A relation between the elemental concentration and the differences obtained for different parts of the same filter was observed. Results suggest that, for the elements studied, data are reproducible to within 5-15%. In the second INAA and PIXE analysis of different sections of the same filter are discussed. Results indicate a good agreement for the determination of K, Fe and Zn by the two techniques.

2012

Three different procedures for sample preparation have been compared for the determination of Cu, Mo and Sb in airborne particulate matter (APM) collected on glass fiber filters using high-resolution continuum source graphite furnace atomic absorption spectrometry (HR-CS GF AAS). Direct solid sample analysis of the ground filters was compared with microwave-assisted acid leaching with aqua regia and ultrasound-assisted extraction also using aqua regia. The main absorption line at 324.754 nm or the secondary line at 216.509 nm was used for the determination of Cu, depending on the analyte content in the samples. The primary absorption line at 313.259 nm was used for Mo and the secondary line at 212.739 nm for Sb determination. The limits of detection (LOD, 3 ) found for the direct solid sampling method, based on ten atomizations of an unused filter were 15 g g −1 for all three analytes, corresponding to 40 ng m −3 for a typical air volume of 1440 m 3 collected over a period of 24 h. The LOD for the other two methods were less than a factor of two inferior, but the total time required for an analysis was significantly longer. The repeatability of the measurements was between 3 and 9% (n = 5), and the results obtained with the three methods did not show any significant difference. The ratio between the three analytes on the filters from areas of intense traffic was found to be around Cu:Mo:Sb ≈ 4:1:1.4, which suggests that the source of all three elements is brake linings, i.e., related to automobile traffic. When the ratio deviated significantly from the above values, the source of contamination was assumed to be of different origin.

2012

Fine-particle pollution in large populated Asian cities can be very high compared with internationally accepted health goals. Much of this fine-particle pollution is produced by motor vehicles, fossil-fuel combustion, industrial processes and even windblown soils from desert regions. As part of a long term project in the Asian region with support from the IAEA, ANSTO has been using nuclear techniques not only to characterize fine-particle pollution, but also to quantify their sources and origins within Vietnam. Fine particles in ambient air are defined as those particles with aerodynamic diameters less than 2.5 μm in diameter. Particles in this size range can be directly absorbed into the blood stream from the lungs, are most efficient at absorbing and scattering visible light and can travel thousands of kilometres from their original source emission points. A full characterisation of these particles, their sources and their origins will help regulators better understand and hence c...

Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 1987

Aerosol particles were collected in the Plomin power plant and the Kolektor factory of copper lamellas using a cascade impactor. The results of the elemental analysis of particles performed using two analytical methods, XRF and PIXE, show very good agreement. Concentrations of Ca, Cr, Fe and Cu in aerosols, calculated using both methods, are given and discrepancies discussed.

Analytical and Bioanalytical Chemistry, 2002

The development of quality control materials for the determination of selected trace elements in air pollution studies is described. Three types of test samples were prepared for proficiency testing: (1) filters loaded with PM10 fraction of urban air particulate matter (APM) using high-volume air samplers, which were subsequently divided into smaller sections, (2) a bulk sample of APM collected in an automobile tunnel in Prague, and (3) simulated air filters loaded with APM using a wet deposition process. Homogeneity of the test samples was studied using instrumental neutron activation analysis, proton induced X-ray emission and atomic absorption spectrometry, and inductively coupled plasma optical emission spectrometry and mass spectrometry. Sufficiently homogeneous samples were prepared by all three procedures. The simulated air filters appeared to be the most suitable test samples for proficiency testing.

Journal of Radioanalytical and Nuclear Chemistry Articles, 1993

Size-fractionated aerosol samples collected with micro-orifice impactors at Camden, NJ, a heavily industrialized urban area, and at two sites near Washington, DC, were analyzed for elemental constituents determined instrumentally from short-lived neutron activation products. A least-squares peak-fitting method was used with impaetor calibration data to determine log-normal distribution parameters, i.e., mass median aerodynamic diameter (MMAD) and geometric standard deviation (og) for particles bearing S, V, Br, and 1. For these elements, MMADs ranged from 0.24 to 0.65 p.m; 0.23 to 0.53 tim; 0.22 to 0.61 ~m, and 0.20 to 0.48 ~m, respectively.