Search

We have conducted a comprehensive, year‐long, sampling campaign for particulate matter (PM) at a site near a major highway, following standard protocols. Total mass, elemental and chemical composition of the fine fractions (PM2.5) of particulates originating from traffic are determined using several complementary techniques. These complementary techniques include gravimetric analysis, X‐ray fluorescence, scanning electron microscopy and energy dispersive spectroscopy, X‐ray diffraction (XRD) and black carbon multiwavelength absorption. Conducting an enrichment factor analysis and correlation coefficient calculations on elements show that Si, Ca, Al, Fe, Ti, Mn, Mg, K, Na and Cr are of crustal origin, while P, Cl and V are enriched slightly from human activities. All other measured elements (Rb, Zr, Ba, Sr, S, Ni, Cu, Zn and Pb) have high enrichment factors and relate to anthropogenic sources. Sulfates in the form of mascagnite and koktaite had the largest contribution to PM2.5 (43% of total PM concentration). Natural pollutants such as quartz, calcite, iron oxide and aluminum oxide originating from the crust also contribute to PM2.5. eBC and elements such as Zn, Ba, Cu, Fe and S are related to traffic emissions such as exhaust emissions and tire, brakes and road erosion. Correlation coefficients and enrichment factor calculations helped identify elements that are related to natural emissions and those related to anthropogenic sources. Being an arid region, the PM2.5 mass concentrations were found to be within or slightly above international air quality standards. [ABSTRACT FROM AUTHOR]

We used a multistage PIXE inertial impactor with nine different aerodynamic diameter ranges (between 16 and 0.06 μm) to sample indoor particulate matter (PM). X-ray fluorescence (XRF) measurements performed at cutoff diameters (CoDs) of 0.25, 0.5, 1, 2, 4, and 8 μm were used to identify elements in various size fractions. Anthropogenic sources were the dominant sources for fine and ultrafine particle sizes. The XRF results show that natural sources also contribute to the fine and ultrafine fractions of pollutants. Scanning electron microscopy and energy-dispersive system analysis were performed on membranes having PM CoDs of 4, 2, 1, 0.5, and 0.25 μm. Elemental mappings show the membranes with PM of CoDs 0.25 and 0.5 μm having S as a dominant element, confirming the results obtained with XRF. Strong correlation among maps of S, N, and O show that ammonium sulfate is the major constituent at these size fractions. Other elements such as Si, Ca, Fe, Al, and Mg show up in smaller amounts at these size fractions but increase for membranes with larger particles. For size fractions larger than 0.5 μm, there is a good correlation between the elemental maps of these elements and oxygen, indicating that these elements exist mostly in oxide forms. The absence of clear N signals and the correlation between the Ca and S maps indicate that S in these size fractions is not due to ammonium sulfate. The presence of Mg, K, Cl, and Na at these CoDs shows that these elements are due to salts originating from sea breeze. [ABSTRACT FROM AUTHOR]

Sum peaks, escape peaks, and diffraction peaks are considered artificial or spurious peaks in energy dispersive X-ray spectrometry. Experimental examples are given, which showed that escape and diffraction peaks can add up to become sum peaks. These artificial peaks are not weak, and great care must be taken to differentiate them from peaks due to impurity or trace elements. The relationship between the intensity of a sum peak and the original peaks is illustrated using computer simulation as well as probability theory. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

ABSTRACT Commercially available hand‐held X‐ray fluorescence (HH‐XRF) spectrometers have their own quantitative analysis software. When the elements Se and Cd in soil samples are measured and quantified, the calculated concentrations sometimes fail by a factor of 1/2 for Cd, although the values obtained for Se are accurate. This is because of the escape depth length of fluorescent X‐rays. Easy ways to overcome this problem are presented; two point calibration, or at least one point and one blank is enough. Problems associated with mercury evaporation from the sample is also discussed. Filter paper analysis is used as an example for the present work, and a five‐filter pile of ash‐less paper is concluded to have better sensitivity than a single paper filter analysis. [ABSTRACT FROM AUTHOR]