Secondary atmosphere

These are the reasons of the difficulty to distinguish the effects on biological systems attributed to normal pollution (primary) and those due to chemical reactions in the atmosphere (secondary pollution). 

The formation of nanoparticles from gaseous precursors is the dominant mechanism for new particle formation in the atmosphere. Secondary mechanical effects, such as shattering of ice or rain particles or abrasion of mineral dust, also lead to increases in particle number density but at sizes larger than the nanoparticle range. As illustrated in Figure 10, the first step in g nanoparticle formation is generally the... 

Cyclophosphamide may be released into the atmosphere secondary to production or through waste streams. If released into the air, it is expected to be present in both vapor and particulate phases at ambient temperature and pressure. Vapor-phase degradation by hydroxyl radicals in general produces a half-life of 5.5 h. Particulate cyclophosphamide will... 

Jang, M., and Kamens, R. M. (2001) Atmospheric secondary organic aerosol formation by heterogeneous reactions of aldehydes in the presence of a sulfuric acid catalyst, Environ. Sci. Technol. 35, 4758—4766. 

Primary cosmic radiation, in the form of high energy nuclear particles, electrons rmd photons from outside the soleU system and from the Sun, continueJly homheU ds our atmosphere. Secondary radiation, resulting from the interaction of the primeuy cosmic rays with atmospheric gas, is present at sea-level rmd throughout the atmosphere. 

Schlesinger RB, Cassee F (2003) Atmospheric secondary inorganic particulate matter the toxicological perspective as a basis for health effects risk assessment. Inhal Toxicol 15 197-235... 

The natural composition of air includes the major gases (N2 78% 02 = 20.9% Ar = 0.9% C02 = 0.035% H2O = 0.53%) and many hundreds of trace components. Some of these can be explained by natural releases or direct industrial activities (primary pollutants) and others, that are formed indirectly by chemical processes in the atmosphere (secondary pollutants). It therefore follows that, in minimizing the environmental impact of industrial activity, not only must direct pollutant releases be considered, but also the release of compounds which may have a role in secondary pollutant production. 

Perraud V, Bruns EA, Ezell MJ, Johnson SN, Yu Y, Alexander ML, Zelenyuk A, Imre D, Chang WL, Dabdub D, Pankow JF, Finlayson-Pitts BJ (2012) Nonequilibrium atmospheric secondary organic aerosol formation and growth. Proceedings of the National Academy of Sciences 109 2836... 

Secondary and tertiary amines are not generally prepared in the laboratory. On the technical scale methylaniline is prepared by heating a mixture of aniline hydrochloride (55 parts) and methyl alcohol (16 parts) at 120° in an autoclave. For dimethylaniline, aniline and methyl alcohol are mixed in the proportion of 80 78, 8 parts of concentrated sulphuric acid are added and the mixture heated in an autoclave at 230-235° and a pressure of 25-30 atmospheres. Ethyl- and diethyl-anihne are prepared similarly. One method of isolating pure methyl- or ethyl-aniline from the commercial product consists in converting it into the Y-nitroso derivative with nitrous acid, followed by reduction of the nitroso compound with tin and hydrochloric acid ... 

Air pollution can be considered to have three components sources, transport and transformations in the atmosphere, and receptors. The source emits airborne substances that, when released, are transported through the atmosphere. Some of the substances interact with sunlight or chemical species in the atmosphere and are transformed. Pollutants that are emitted directiy to the atmosphere are called primary pollutants pollutants that are formed in the atmosphere as a result of transformations are called secondary pollutants. The reactants that undergo transformation are referred to as precursors. An example of a secondary pollutant is O, and its precursors are NMHC and nitrogen oxides, NO, a combination of nitric oxide [10102-43-9] NO, and NO2. The receptor is the person, animal, plant, material, or ecosystem affected by the emissions. 

The GdAlgB O QiCe ", Tb " is synthesized by a soHd-state firing of the rare-earth coprecipitated oxide plus boric acid and MgCO at 900° C in a slightly reducing atmosphere. As in the case of the lanthanum phosphate phosphor, a flux is usually used. The synthesis of this phosphor is further comphcated, however, by the fact that it is a ternary system and secondary phases such as gadolinium borate form and must then react to give the final phosphor. 

Water and carbon dioxide from the atmosphere can be absorbed by the amines to form hydrates and carbamates, from primary and secondary amines, respectively. 

For low pressure pipelines that have ports open to the atmosphere, eg, sewers or closed effluent culverts, samplers are designed to sample through manholes. In a typical system, the Hquid is lifted through a suction line into the sampling chamber under vacuum. When filled, the vacuum shuts off, and the sample drains into a sample jar. A secondary float prevents any Hquid from reaching the vacuum pump. The suction line then drains by gravity back to the source. 

Other alkaline primary cells couple zinc with oxides of mercury or silver and some even use atmospheric oxygen (zinc—air cell). Frequendy, zinc powder is used in the fabrication of batteries because of its high surface area. Secondary (rechargeable) cells with zinc anodes under development are the alkaline zinc—nickel oxide and zinc—chlorine (see Batteries). 

Air pollution (qv) problems are characteri2ed by their scale and the types of pollutants involved. Pollutants are classified as being either primary, that is emitted direcdy, or secondary, ie, formed in the atmosphere through chemical or physical processes. Examples of primary pollutants are carbon monoxide [630-08-0] (qv), CO, lead [7439-92-1] (qv), Pb, chlorofluorocarbons, and many toxic compounds. Notable secondary pollutants include o2one [10028-15-6] (qv), O, which is formed in the troposphere by reactions of nitrogen oxides (NO ) and reactive organic gases (ROG), and sulfuric and nitric acids. 

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