Atmosphere particulate composition

Gaarenstroom, P. D., Perone, S. P. and Moyers, J. L. (1977). "Application of Pattern Recognition and Factor Analysis for Characterization of Atmospheric Particulate Composition in Southwest Desert Atmosphere," Environmental Science... 

The methods just noted tell something about the physical characteristics of atmospheric particulate matter but nothing about its chemical composition. One can seek this kind of information for either individual particles or all particles en masse. Analysis of particles en masse involves analysis of a mixture of particles of many different compounds. How much of... 

Despite the difficulties, there have been many efforts in recent years to evaluate trace metal concentrations in natural systems and to compare trace metal release and transport rates from natural and anthropogenic sources. There is no single parameter that can summarize such comparisons. Frequently, a comparison is made between the composition of atmospheric particles and that of average crustal material to indicate whether certain elements are enriched in the atmospheric particulates. If so, some explanation is sought for the enrichment. Usually, the contribution of seaspray to the enrichment is estimated, and any enrichment unaccounted for is attributed to other natural inputs (volcanoes, low-temperature volatilization processes, etc.) or anthropogenic sources. 

We now consider the abstract presented in excerpt 8G, which reverses the emphases observed in excerpts 8C-8F. In excerpt 8G, moves 1 and 2 comprise the bulk of the abstract, and move 3 is just a single sentence. Much of the abstract is used to elucidate important gaps in the field that (1) a size-based standard for regulating atmospheric particulate matter is inadequate because it does not take into account chemical composition, and (2) compositional analyses are difficult, especially for metals, because they often exist in multiple oxidation states. These gaps help to establish the relevance of the authors work. Only in the last sentence do the authors mention their work specifically (move 3). Here, they identify their method (micro-XANES) and tell readers what results will be presented at the conference. 

Move 1] Currently atmospheric particulate matter is regulated based on various size categories because of the apparent association between particle size and adverse health effects. [Move 2] However, the current size-based understanding of atmospheric particles is relatively crude because it does not account for differences in the chemical composition of these particles. Presumably a chemically reactive particle has a greater potential for damage than a chemically inert particle of comparable size. Of the metals potentially... 

The Beijing area in north China is well situated for investigating relationships between the elemental composition of atmospheric particulate matter and air mass movements. The municipality of Beijing (Beijing shi) has a population of 7 million, half of whom live in the city proper, and pollution sources of trace gases... 

Lindberg, J. D., 1975. The composition and optical absorption coefficient of atmospheric particulate matter, Opt. Quant. Electron., 7, 131-139. 

On the other hand, comparison of the average PAH profiles in the sediments (Fig. 10) with snow deposition [62] and atmospheric PAH gas and particulate phases distribution [34] shows a good agreement between the PAH composition in the sediments and in the atmospheric particulate phase (r2 = 0.94 p < 0.01) and snow deposition (r2 = 0.92 p < 0.01). 

Struempler AW. 1975. Trace element composition in atmospheric particulates during 1973 and the summer of 1974 at Chadron, Neb. Environ Sci Technol 9 1164-1168. 

The major element content and mineralogy of air-borne particles reflect closely those of continental soils and shales, although atmospheric particulates also include materials of oceanic origin (Delaney et al., 1967), and show considerable enrichments in some trace metals (Buat-Menard and Chesselet, 1979). The average composition of shales and soils (Table 9.8) was chosen to represent the properties of dust transported from the continents to the ocean. Fluxes of elements in atmospheric transport to the ocean are given in Table 9.14. 

Mroz, E.J. and Zoller, W.H., 1975. Composition of atmospheric particulate matter from the eruption of Heimaey, Iceland. Science, 190 461—464. 

Table 14.5. Atmospheric particulate matter elemental composition and the relative concentrations (Skua Lake, 1986-1987)...

Table 14.7. Atmospheric particulate matter concentrations (Skua Lake, Italian station, 1988- elemental -1989) composition and the relative...

The solubility of SO2 in water is strongly dependent on its pH, becoming limited below pH = 4. The presence of other pollutants can be important as they affect the pH of the liquid layer on the surface, which may also be buffered by corrosion products per se. Nitric acid deposits quite readily, for example, and could lower the pH and thus inhibit SO2 uptake. On the other hand, many atmospheric particulates are basic, and the limited literature on dew chemistry (Cadle and Goblicki) (22) does not indicate acidic dew composition, (it should be noted that these data were all taken in low SO2 environments). 

Modern bulk analysis methods make possible non-destructive chemical identification, which means that the sample remains intact after the analysis. Such a procedure is provided by electron microprobe or X-ray fluorescence analyses, in which the sample is irradiated by electron beams or X-rays and the elemental composition is determined on the basis of induced characteristic X-ray emissions. These methods have been successfully employed to study both stratospheric (Junge, 1963) and tropospheric (Gillette and Blifford, 1971) aerosol particles. Neutron activation analysis is also widely used to identify the chemical composition of atmospheric particulate matter (e.g. Duceef ai, 1966 Rahn etal., 1971) this is also a non-destructive procedure. 

Kadowaki, S. (1977). Size distribution and chemical composition of atmospheric particulate nitrate in the Nagoya area. Atmos. Environ. 11, 671-695. 

The concentration of atmospheric aerosols varies considerably in space and time. This variability of the aerosol concentration field is determined by meteorology and the emissions of aerosols and their precursors. For example, the annual average concentration of PM2.5 in North America varies by more than an order of magnitude as one moves from the clean remote to the polluted urban areas of Mexico City and southern California (Figure 8.24). Sulfate dominates the fine aerosol composition in the eastern United States, while organics are major contributors to the aerosol mass everywhere. Nitrates are major components of the PM2.5 in the western United States. The EC makes a relatively small contribution to the particle mass in many areas, but because of its ability to absorb light and its toxicity, it is an important component of atmospheric particulate matter. 

Thermodynamic calculations for multicomponent atmospheric particulate matter involve either the minimization of the Gibbs free energy of the system (see Section 10.1.3) or solution of a system of nonlinear algebraic equations [see equation (10.30)] corresponding to the equilibrium reactions taking place in the system. However, there are two major complications (1) the composition of the system (e.g., existence of a given salt) is not known a priori and (2) if the particles are aqueous, the activity coefficient of each... 

The campaigns at the 4 sites were conducted consecutively, not simultaneously. Therefore, seasonal changes in aerosol composition will have influenced the results. Although the consecutive sampling pattern is not very suitable for a direct comparison of the localities, our study provides a detailed information on distribution of compounds producing multiple biological effects in the inhalable fraction of atmospheric particulate matter and the gas-phase. 

The elemental composition of atmospheric particulates can be used for the identification of the origin of the particulates. A set of characteristic correlating elements may indicate, for example, crustal... 

The chemical composition of atmospheric particulate matter is quite diverse. Among the constituents of inorganic particulate matter found in polluted atmospheres are salts, oxides, nitrogen compounds, sulfur compounds, various metals, and radionuclides. In coastal areas, sodium and chlorine get into atmospheric par-... 

The major constituents of atmospheric particulate soil, dispersed as an aerosol, are carbon soot, organic matter, and inorganic carbonates [5]. The composition of dust collected from air filters is variable it may even vary with the season of the year [6]. 

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