Atmosphere formation

Debye-Huckel theory assumes complete dissociation of electrolytes into solvated ions, and attributes ionic atmosphere formation to long-range physical forces of electrostatic attraction. The theory is adequate for describing the behaviour of strong 1 1 electrolytes in dilute aqueous solution but breaks down at higher concentrations. This is due to a chemical effect, namely that short-range electrostatic attraction occurs... 

Singh FIB, Lillian D, Appleby A, et al. 1975. Atmospheric formation of carbon tetrachloride from tetrachloroethylene. Environ Lett 10 253-256. 

Figure 5-8 A Pb-Pb isochron that determined the age of the Earth to be about 4.55 Ga. Stony and iron meteorites as well as a sediment of the Earth are plotted on a Pb-Pb isochron. The sediment, as a "bulk sample of the silicate Earth in terms of Pb isotopes, plots on the same line as the meteorites, suggesting that the Earth and meteorites formed at the same time and are the same age. Erom Patterson (1956). Later studies reveal a more detailed evolution history of the Earth, including core formation (about 4.53 Ga), atmospheric formation (about 4.45 Ga), and crustal evolution.

Grosjean, D., Formic Acid and Acetic Acid Emissions, Atmospheric Formation, and Dry Deposition at Two Southern California Locations, Atmos. Environ., 26A, 3279-3286(1992). 

The term binary homogeneous nucleation is used to describe the formation of particles from two different gas-phase compounds such as sulfuric acid and water such nucleation can occur when their individual concentrations are significantly smaller than the saturation concentrations needed for nucleation of the pure compounds. It is believed that in the atmosphere, formation of particles from low-volatility gases occurs not by condensation of a single species but rather by the formation and growth of molecular clusters involving at least two, and as described shortly, probably three or more different species. 

F. REACTIONS OF GAS-PHASE PAHs ATMOSPHERIC FORMATION OF MUTAGENIC NITROARENES... 

Atmospheric Formation of Nitro-PAHs and Nitro-PACs... 

Additionally, in two different monitoring campaigns conducted in the center of Milan, Italy, Ciccioli and co-workers (1993) reported 2-nitrofluoranthene, 2-nitropyrene, and 1-nitropyrene were the only ni-troarenes detected. Subsequently, in a comprehensive study of the atmospheric formation and transport of 2-nitrofluoranthene and 2-nitropyrene, they established their presence and levels in ambient particles collected at sites located in urban, suburban, forest, and remote areas in Europe, Asia, America, and Antarctica (Ciccioli et al., 1996, and references therein see also Ciccioli et al., 1995). 

Figure 10.35 is the GC-MS m/z 247 profile of the nitrofluoranthenes and nitropyrenes in an extract of an ambient particle sample collected at night (Arey et al., 1988b). The high ratio of 2-nitrofluoranthene to 2-nit-ropyrene observed in this nighttime sample is indicative of nighttime gas-phase NO, radical reactions (for a review, see Kwok et al., 1994b). An NO, radical initiated mechanism for atmospheric formation of 2-nitrofluoranthene is shown in Fig. 10.36 (Atkinson and Arey, 1997 Arey, 1998a, and references therein). Analogous to the OH reaction, NO, is proposed to add to the ring to form a fluoranthene-NO, adduct, followed by ortho addition of N02 and subsequent loss of HNO,. This reaction is noteworthy because of its selectivity i.e., only 2-nitrofluoranthene is formed, and in high yield (24%) compared to the OH-initiated daytime reaction (3%).

Zielinska, B J. Arey, and R. Atkinson, The Atmospheric Formation of Nitroarenes and Their Occurrence in Ambient Air, in Nitroarenes Occurrence, Metabolism, and Biological Impact (P. C. Howard, S. S. Hecht, and F. A. Beland, Eds.), pp. 73-84, Plenum, New York, 1990. 

Harley, R. A and G. R. Cass, Modeling the Concentrations of Gas-Phase Toxic Organic Air Pollutants Direct Emissions and Atmospheric Formation, Environ. Sci. Technol., 28, 88-98(1994). 

In chemical kinetics this kind of investigation is unique. The process occurs not only in combustion. In strong explosions in the atmosphere formation of nitrogen oxide plays an important role, changing the optical properties of the... 

Abe Y, Matsui T (1986) Early evolution of the Earth Accretion, atmosphere formation, and thermal history. J Geophys Res 91(B13) E291-E302... 

Figure 1. Schematic representation of pathways for atmospheric formation of sulfuric and nitric acids and their salts. (Reproduced with permission from Ref. 28. Copyright 1986 Lewis Publishers, Inc.)...

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