Source emitted material, atmospheric

Source-dispersion and receptor-oriented models have a common physical basis. Both assume that mass arriving at a receptor (sampling site) from source j was transported with conservation of mass by atmospheric dispersion of source emitted material. From the source-dispersion model point of view, the mass collected at the receptor from source j, Mj, Is the dependent variable which Is equal to the product of a dispersion factor, Dj (which depends on wind speed, wind direction, stability, etc.) and an emission rate factor, Ej, 1. e. , ... 

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 oceans of the world are an important natural source of pollutant material. The ocean is continually emitting aerosols to the atmosphere, in the form of salt particles, which are corrosive to metals and paints. The action of waves on rocks reduces them to sand, which may eventually become airborne. Even the shells washed up on the beach are eroded by wave and tidal action until they are reduced to such a small size that they too may become airborne. 

The major sources of atmospheric methane are biogenic. They include the anaerobic fermentation of organic material in swamps, tropical rain forests, paddies, and in the digestive systems of livestock as well as termites (Ehhalt, 1974 Zimmerman et al., 1982). It is interesting to note that while virtually all the CH4 emitted to the atmosphere is biogenically produced, man s activities influence a large fraction of the production — specifically that produced by enteric fermentation in livestock and CH4... 

Many various types of industrial activities result in pollution of the atmosphere. The furnaces at the earlier mines were sources of pollution. Modern electrochemical industry brought other types of problems. Fluorine exhausted from aluminum factories has caused great damage in the vicinity. Some of these factories emit organic components that may be dangerous to health. Smoke from ferrosilicium, ferromanganese, and ferrochrome factories is really noticeable. Many factories which refine heavy metals spread polluting material. 

The biosphere is a major contributor to the atmosphere of heavier hydrocarbons. Fritz Went (8, 9), who first recognized the global extent of smog, pointed out the general importance of natural emissions from vegetation. He estimated that sources in the biosphere annually emit between 170 X 10 and 10 tons of hydrocarbon material to the atmosphere. Went also observed that these materials are mainly in the terpene class and that, because they are photochemically reactive, these materials are polymerized in atmospheric photochemical reactions to form an organic aerosol. He attributes the blue haze found in many forested areas to the optical effects of this aerosol. 

It is our estimate that all pollutant sources result in about 300 X 10 tons per year of particulate material being introduced into the atmosphere and that pollutant and natural sources combined amount to about 3000 X 10 tons per year. Thus, on a global scale 30 X 10 tons per year of pollutant photochemical aerosols are about 10% of the total pollutant aerosols and about 1% of the total annual atmospheric aerosol production. The 200 X 10 tons of aerosol particles resulting from the photochemical scavenging reactions involving natural organic emissions is somewhat less than 10% of the total aerosols emitted to the global atmosphere. 

Air pollution is usually defined as the presence in the outdoor atmosphere, of substances put there directly or indirectly by an act of man, in amounts which are detrimental to health and safety or interfere with the fulJ jise of materials or property, e.g. made from polymeric materials. Man is not the only agent able to pollute the atmosphere. There are many natural processes that do so such as pollination of plants, volcanic emptions, dust stormes and forest fires. There are also secondary pollutants in the atmosphere, formed in the air from primary pollutants, due to acts by man, e.g. smoke, industrial pollutants and photochemical smog formed in the air from substances emitted from automobile exhaust and other sources. 

Due to the abundance and the nature of the primary compounds involved in these reactions, Cl chemistry has become a major area of research interest. CH4 (main component of natural gas) may be considered as a raw material for the next decades to produce various organic intermediates (chemicals, liquid fuels), as well as a principal source of energy. CO2 is the largest by-product emitted to the atmosphere and partially responsible for the green house effect. For this latter reason, its reutilisation is strongly desirable. CH3OH is a synthetic compound that allows numerous chemical transformations of great interest in the production of intermediates for the chemicals industry. Also CO (or CO + H2 mixture, usually called synthesis... 

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