Atmospheric particulates

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 

Hierarchical clustering and non-linear mapping group together elements with small distances  

Classification of lake sediments by means of factor analysis and hierarchical clustering has been reported by Hopke et. al. C1103- For a set of 79 sediment samples, 32 characteristic properties were determined (e.g. concentration of 15 elements, percent organic matter, criteria of the particle size distribution, water depth). Cluster analysis detected a single cluster for samples from the centre of the lake and three different clusters for samples from near the shore. 

Peterson C226, 2271 used pattern recognition methods for predicting sulfur dioxide concentrations from meteorological parameters. For days with consistent wind direction, 75 % of the calculated values agreed with the values observed at several locations in the metropolitan St..Louis (Mi ssouri)- 

Several pattern recognition programs have been applied by WegscheideV et. al. C3261 to the interpretation of a set of trace element concentrations in groundwater. The data set consisted of 149 samples with up to ten measurements made on each sample. Four different origins of these samples have been successfully visualized by display methods. 

Unless particulates are being collected in a grossly polluted atmosphere, large volumes of air must be filtered to give sufficient amounts of material for analysis by flame spectrometry. The filters are then ashed and/or digested prior to analysis. Unused filters are usually used for blank preparation. Pio and Hall18 have published a useful concise review of atmospheric particulate sampling, and a more detailed account has been written by Spurny.19 

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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... 

Atmospheric particulates (sea salt, carbonaceous soot, and sulfuric acid aerosols) are known to provide a condensed phase for conq>lex heterogeneous chemistry to occur. Although the presence of atmospheric particulates are known to alter trace gas concentrations, details of the specific chemical mechanisms for condensed phase chemistry have not been identified. 

Atmospheric particulate emissions can be reduced by choosing cleaner fuels. Natural gas used as fuel emits negligible amounts of particulate matter. Oil-based processes also emit significantly fewer particulates than coal-fired combustion processes. Low-ash fossil fuels contain less noncombustible, ash-forming mineral matter and thus generate lower levels of particulate emissions. Lighter distillate oil-based combustion results in lower levels of particulate emissions than heavier residual oils. However, the choice of fuel is usually influenced by economic as well as environmental considerations. 

Environmental impacts. Discharges to atmosphere (particulates and other toxic or noxious emissions), surface waters (scrubbing water), and land (furnace residues) may require extensive treatment to assure protection of the environment. 

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. 

Yamanchi T, T Handa (1987) Characterization of aza heterocyclic hydrocarbons in urban atmospheric particulate matter. Environ Sci Technol 21 1177-1181. 

Scott DR, Hemphill DC, Hoiboke LE, et al. 1976. Atomic absorption and optical emission analysis of NASN atmospheric particulate samples for lead. Environ Sci Technol 9 877-880. 

I,, = 0.7 h on silica gel, tA = 2.2 h on alumina and tA = 44 h on fly ash for different atmospheric particulate substrates determined in the rotary photoreactor (appr. 25 pg/g on substrate) (Behymer Hites 1985) direct photolysis tA = 9.08 h (predicted-QSPR) in atmospheric aerosol (Chen et al. 2001). Photodegradation k = 3 x 10-5 s in surface water during the summertime at mid-latitude (Fasnacht Blough 2002)... 

Photolysis half-lives on different atmospheric particulate substrates (approx. 25 (xg/g on substrate) t,2 = 7.0 h on silica gel, t,/2 = 22 h on alumina and t,/2 = 29 h on fly ash (Behymer Hites 1985) first order daytime photodegradation rate constants for adsorption on wood soot particles in an outdoor Teflon chamber k = 0.0077 min-1 with 1000-2000 ng/mg loading and k = 0.0116 min-1 with 30-350 ng/mg loading (Kamens et al. 1988) ... 

Behymer, T.D., Hites, R.A. (1985) Photolysis of polycyclic aromatic hydrocarbons adsorbed on simulated atmospheric particulates. 

Muel, B., Saguem, S. (1985) Determination of 23 polycyclic hydrocarbons in atmospheric particulate matter of the Paris area and photolysis by sunlight. Int l. J. Environ. Anal. Chem. 19, 111-131. 

Elevated levels of molybdenum in nonbiological materials have been reported near certain mines, power plants, and oil shale deposits, as well as in various sewage sludges, fertilizers, and agricultural drainwaters (Table 30.1). Molybdenum is concentrated in coal and petroleum, and the burning of these fuels contributes heavily to atmospheric molybdenum (King et al. 1973). Combustion of fossil fuels contributes about 5000 metric tons of molybdenum annually to the atmosphere atmospheric particulates contain about 0.001 pg Mo/m3 air (Goyer 1986). 

The main reason for sampling for atmospheric particulates is to estimate the concentrations that are inhaled and deposited in the lungs. Sampling methods and the interpretation of data relevant to health hazards are relatively complex industrial hygienists, who are specialists in this technology, should be consulted when confronted with this type of problem. 

Cooper, P. L. and Abbatt, J. P. D. Heterogeneous interactions of OH and HO2 radicals with surfaces characteristic of atmospheric particulate matter, J. Phys. Chem., 100,2249-2254,1996. 

Chabas, A. and Lefevre, R. A. (2000). Chemistry and microscopy of atmospheric particulates at Delos (Cyclades-Greece). Atmospheric Environment 34 225-238. 

SRM 1648 ( ) Urban Atmospheric Particulate Trace Elements nist(5)... 

Grosjean, D. Solvent extraction and organic carbon determination in atmospheric particulate matter The organic extraction-organic carbon analyzer (OE-OCA) technique. Anal. Chem. 47 797-805, 1975. 

Riggin RM, Howard CC, Scott DR, et al. 1983. Determination of benzidine related congeners and pigments in atmospheric particulate matter. J Chromatogr 21 321-325. 

Guidotti M, Giovinazzo R, Cedrone O, Vital M (1998) Investigation on the presence of aromatic hydrocarbons, persistent organochlorine compounds, phthalates and the breathable fraction of atmospheric particulate in the air of Rieti urban area. Ann Chim-Rome 88 419 27... 

The determination of the levels of drugs of abuse in atmospheric particulates collected at regular air quality monitoring sites could constitute a useful pubhc health tool with a range of potential applications... 

Photochemical transformation of contaminants occurs in surface waters or when adsorbed on atmospheric particulates, which originate from the subsurface solid... 

The importance of surface analysis for evaluating the environmental effects of toxic substances is becoming more apparent as the result of recent work in this field. Chapter 9 describes ESCA, Auger, Ion Microprobe, and SIMS surface analysis techniques for atmospheric particulates. These techniques overcome the obvious limitations of bulk analysis, that is, the wide variability in the physicochemical characteristics of different particles. 

Surface Microanalytical Techniques for the Chemical Characterization of Atmospheric Particulates... 

Simoneit BRT, Elias VO, Organic tracers from biomass burning in atmospheric particulate matter over the Ocean, Mar Ghem 69 301-312, 2000. 

Simoneit BRT, Elias VO, Kobayashi M, Kawamura K, Rushdi AI, Medeiros PM, Rogge WE Didyk BM, Sugars — dominant water-soluble organic compounds in soils and characterization as tracers in atmospheric particulate matter. Environ Sci Technol 38 5939-5949, 2004. 

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. 

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