Element emission factor

Hasanen, E., Aunela-Tapola, L. et al. 1997. Emission factors and annual emissions of bulk and trace elements from oil shale fuelled power plants. The Science of the Total Environment, 198, 1-12. 

The similar emission factors reported for mercury and nickel (28), even though the latter is approximately 1000 times more concentrated in coal, probably reflect volatility differentials. Volatile elements commonly considered the most hazardous are Be, F, As, Se, Cd, Pb, and Hg (4). Volatility and dispersion are associated with multimedia contamination (7) which necessitated the determination of likely absorption through inhalation and ingestion when national ambient standards for mercury were developed (29). 

Similarly, different results have been found for the impact of brake wear particles. While unequivocally a strong enrichment of brake-related chemical trace elements (Sb, Ba, Cu) is found at trafficked sites [63], the quantification of overall PM contribution from brake wear is associated with uncertainties. An even wider range of emission factors was found for re-suspension of road dust (cf. Table 4). It should be noted that re-suspension may be a strong source of PM during wintertime when de-icing salt is spread out. For a traffic site in southern Germany exceedance of the daily PM limit value could be tracked back to road salting in 12 of 43 cases [66]. 

Bukowiecki N, Lienemann P, Hill M et al (2009) Real-world emission factors for antimony and other brake wear related trace elements size-segregated values for light and heavy duty vehicles. Environ Sci Technol 43 8072-8078... 

Another source of metallic contamination in the studied region comes from the residual oil combustion used for electric utilities and fluvial and terrestrial transportation. Using the selected emission factors (quantity of trace element released by quantity of material consumed) given by Nriagu and Pacyna (1988) and Nriagu (1989), the electric-power production installed in the Amazonian states and the fuel consumption used for transportation (Ministerio de Minas... 

Laursen K. K., Ferek R. J., and Hobbs P. V. (1992) Emission factors for particulates, elemental carbon, and trace gases from the Kuwait oil fires. J. Geophys. Res. 97,14491 -14497. 

With respect to contributions of other mobile sources to the atmospheric burden of trace metals, very few data are available. The National Aeronautics and Space Administration in 1974 published calculated annual average ambient concentrations at or near airports of 49 trace elements attributable to aircraft most values were less than numbers. Of interest, however, are the estimates for the environmentally important metals, titanium, vanadium, and cadmium these were given as 24 ng/m , 0.12 ng/m and < 14 ng/m , respectively (56). EflForts to characterize aircraft emissions and to develop emissions factors by means of dynamometer tests are under way. One such experiment is being performed at Pratt and Whitney under contract to the Environmental Protection Agency results from this study should be available in mid-1978 (57). 

The published sensitivity factors are obtained with specific instruments and standard samples of pure elements. Sensitivity factors are subject to change with different samples and developments in instruments. For example, chemical contamination on a sample surface affects the accuracy of using Equation 7.3. For an AES spectrum, the matrix composition affects the efficiency of Auger emissions because the backscattered electrons in the matrix... 

Several factors may affect the flame emission of a given element and lead to interference with the determination of the concentration of given element. The factors may be broadly classified as (a) spectral interferences and (6) chemical interferences. 

Pacyna JM (1986a) Emission factors of atmospheric elements. In Nriagu JO and Davidson CI, eds. 

So far, considerable information of the gaseous exhaust pipe emission factors and some of particulate matter is available from the 1990s. More recent studies reported emission factors for PM mass, organic carbon (OC), elemental carbon (EC) and some metals, which improved present knowledge about composition and size distribution of particulate motor vehicle emissions, and more important which allowed the creation of emission profiles—a prerequisite for source apportionment studies with statistic methods such as chemical mass balance models. However, since fuel composition, engines and vehicle technologies evolve (Kleeman et al. 2000) data on the combined mass emission rate and chemical composition of primary particle emissions from motor vehicles need to be updated periodically. 

This contribution comprehensively reviews the literature reported for particulate emissions of motor vehicles operated under real-world conditions. This article will mainly focus on the results published for size segregated emissions factors of particle mass, elemental and organic carbon, crustal components and selected trace metals, since information is important for health effects studies and source reconciliation modeling efforts. 

There arc two principal ways in which surface concentration data may be obtained by the evaluation of XPS intensities. One relies on a first-principle description of photoelectron emission from a solid surface, the other on empirically determined elemental. sensitivity factors (cf. Chapter 4 and 5). Either approach can be used in its simplest form to estimate elemental surface concentration ratios from XPS intensity ratios for a catalyst surface, provided the sample is homogeneous and isotropic, i.e.. all elements are uniformly distributed in the surface layer sampled by XPS. However, a heterogeneous catalyst is in fact just that—heterogeneous it can be multipha.se and of complex structure. Operative words here are porosity, inner and outer surface, texture, segregation, etc. Nevertheless the simple procedures have been used extensively in catalyst characterization studies for straightforward interpretation of XPS in-... 

Equation (A 1.6.94) is called the KHD expression for the polarizability, a. Inspection of the denominators indicates that the first temi is the resonant temi and the second temi is tire non-resonant temi. Note the product of Franck-Condon factors in the numerator one corresponding to the amplitude for excitation and the other to the amplitude for emission. The KHD fonnula is sometimes called the siim-over-states fonnula, since fonnally it requires a sum over all intennediate states j, each intennediate state participating according to how far it is from resonance and the size of the matrix elements that coimect it to the states i. and The KHD fonnula is fiilly equivalent to the time domain fonnula, equation (Al.6.92). and can be derived from the latter in a straightforward way. However, the time domain fonnula can be much more convenient, particularly as one detunes from resonance, since one can exploit the fact that the effective dynamic becomes shorter and shorter as the detuning is increased. 

In principle, therefore, the surface concentration of an element can be calculated from the intensity of a particular photoelectron emission, according to Eq. (2.6). In practice, the method of relative sensitivity factors is in common use. If spectra were recorded from reference samples of pure elements A and B on the same spectrometer and the corresponding line intensities are and respectively, Eq. (2.6) can be written as... 

Because of the long time scale involved in the s-process, unstable nuclides formed by (n.y) reactions have time to decay subsequently by decay (electron emission). The crucial factor in determining the relative abundance of elements... 

More detailed statistical analyses (chemical element balance, principal component analysis and factor analysis) demonstrate that soil contributes >50% to street dust, iron materials, concrete/cement and tire wear contribute 5-7% each, with smaller contributions from salt spray, de-icing salt and motor vehicle emissions (5,93-100). A list is given in Table VII of the main sources of the elements which contribute to street dust. 

Both emission and absorption spectra are affected in a complex way by variations in atomisation temperature. The means of excitation contributes to the complexity of the spectra. Thermal excitation by flames (1500-3000 K) only results in a limited number of lines and simple spectra. Higher temperatures increase the total atom population of the flame, and thus the sensitivity. With certain elements, however, the increase in atom population is more than offset by the loss of atoms as a result of ionisation. Temperature also determines the relative number of excited and unexcited atoms in a source. The number of unexcited atoms in a typical flame exceeds the number of excited ones by a factor of 103 to 1010 or more. At higher temperatures (up to 10 000 K), in plasmas and electrical discharges, more complex spectra result, owing to the excitation to more and higher levels, and contributions of ionised species. On the other hand, atomic absorption and atomic fluorescence spectrometry, which require excitation by absorption of UV/VIS radiation, mainly involve resonance transitions, and result in very simple spectra. 

An important application field of factor and principal component analysis is environmental analysis. Einax and Danzer [1989] used FA to characterize the emission sources of airborne particulates which have been sampled in urban screening networks in two cities and one single place. The result of factor analysis basing on the contents of 16 elements (Al, B, Ba, Cr, Cu, Fe, Mg, Mn, Mo, Ni, Pb, Si, Sn, Ti, V, Zn) determined by Optical Atomic Emission Spectrography can be seen in Fig. 8.17. In Table 8.3 the common factors, their essential loadings, and the sources derived from them are given. 

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