Sulfur anthropogenic

A substantial portion of fhe gas and vapors emitted to the atmosphere in appreciable quantity from anthropogenic sources tends to be relatively simple in chemical structure carbon dioxide, carbon monoxide, sulfur dioxide, and nitric oxide from combustion processes hydrogen sulfide, ammonia, hydrogen chloride, and hydrogen fluoride from industrial processes. The solvents and gasoline fractions that evaporate are alkanes, alkenes, and aromatics with relatively simple structures. In addition, more complex... 

R. Krol SE and V. A, Grinenko (eds.). Stable Isotopes Natural and Anthropogenic Sulfur in the Environment, SCOPE Report 43. Wiley. Chichesier. 1991. 466 pp,... 

Feedbacks may be affected directly by atmospheric CO2, as in the case of possible CO2 fertilization of terrestrial production, or indirectly through the effects of atmospheric CO2 on climate. Furthermore, feedbacks between the carbon cycle and other anthropogenically altered biogeochemical cycles (e.g., nitrogen, phosphorus, and sulfur) may affect atmospheric CO2. If the creation or alteration of feedbacks have strong effects on the magnitudes of carbon cycle fluxes, then projections, made without consideration of these feedbacks and their potential for changing carbon cycle processes, will produce incorrect estimates of future concentrations of atmospheric CO2. 

Figure 13-6a (Ivanov, 1983) is a depiction of the natural global sulfur budget. Figure 13-6b depicts the budget with natural and anthropogenic sources. Table 13-2 serves to explain Fig. 13-6 and includes the wide range of estimates of various fluxes, and demonstrates the degree of uncertainty inherent in such approaches.

Little snlfnr is re-emitted from wetlands into the atmosphere. Table 8.7 gives estimates of global emissions of volatile sulfur compounds from different sources. Total emissions are in the range 98 to 120 Tg (S) year 75 % is anthropogenic, mainly from fossil fnel combustion in the northern hemisphere. The main natural sources are the oceans and volcanoes. Wetlands and soils contribnte less than 3 % of the total emission. 

In contrast to the fate of silicates, a catchment exhibiting a small area of so-called Biindner Schiefer, a sandy-marly schist containing soluble anhydrite or gypsum, will produce a remarkably high weathering rate for the entire basin. This effect arises in the alpine catchments of the Ticino, Rhine, and Rhone. The occurrence of Biindner Schiefer also causes sulfate concentrations in the range of 0.5-1 mmol in rivers. Natural and anthropogenic atmospheric sulfur... 

Fig. 3.34 S-isotope composition of (a) natural and (b) anthropogenic sulfur sources in the atmosphere, DMS Dimethyl-sulfide...

The isotopic compositions of the industrial sulfur sources are generally so variable, that the assessment of anthropogenic contributions to the atmosphere is extremely difficult. Krouse and Case (1983) were able to give semiquantitative estimates for a unique situation in Alberta where the industrial SO2 had a constant value near 20%c. Generally, situations are much more complicated which limits the fingerprint character of the sulfur isotope composition of atmospheric sulfur to such rare cases. 

In the case of these two regions there is a natural source of airborne salinity the waters of the Atlantic Ocean, the Gulf of Mexico and the Caribbean Sea. Airborne salinity plays an important role in determining corrosion aggressivity in Cuba [1-4] and in the Yucatan Peninsula [2, 5-6], Other anthropogenic contaminants can be present also in this region, particularly sulfur compounds coming from the oil production and manufacture industries and... 

Sulfur dioxide is produced by both natural and anthropogenic sources. The most important of the natural sources are volcanic eruptions, which account for about 40 percent of all natural emissions of the gas. Since volcanic eruptions are episodic events, the amount of sulfur dioxide attributable to this source in any one year varies widely. Other natural sources of the gas are forest fires and other natural burns, biological decay, and certain metabolic processes carried out by living organisms, especially marine plankton and bacteria. Natural sources release about 27.5 million short tons (25 million metric tons) of sulfur dioxide per year. 

The most important anthropogenic source of sulfur dioxide are power generating plants, which account for about 70 percent of all the gas produced in the United States. Another 25 percent of the sulfur dioxide emitted in the country is from a variety of industrial and manufacturing operations. Less than 5 percent of the gas is produced by motor vehicles and other forms of transportation. 

Particulate matter is the term used to describe solid particles and liquid droplets found in the atmosphere. Particulates are produced by a host of natural and anthropogenic sources. Mist and fog are both forms of natural particulates, as are windblown soil, dust, smoke from forest fires, and biological objects, such as bacteria, fungal spores, and pollen. The incomplete combustion of fossil fuels is one of the most important anthropogenic (human-made) sources of particulates. Such processes release unhurned carbon particles, oxides of sulfur and nitrogen, and a host of organic compounds into the air. 

In short, while the focus has been primarily on sulfuric and nitric acids as a source of acid deposition, it is clear that organic acids can also contribute significantly. The gas-phase concentrations of the simplest carboxylic acids, formic acid and acetic acid, are relatively high even in remote regions, of the order of a ppb. Both natural and anthropogenic sources have been... 

---