Sulfur long range transport

Table III shows the loadings table based on concentrations. Factor 1, which explains 44% of the variance, includes all the usual crustal elements at high loadings plus Zn and Pb at much weaker loadings. Factor 2 includes Pb and S, but only at relatively weak loadings, associated with SE winds. This direction is consistent with the long range transport of sulfur from the Ohio Valley, but no obvious Pb sources are apparent in the SE direction. Note that Ca is present on only one factor, with a relatively high loading (0.87).

Acid rain arises from the oxidation of S02 and N02 in the troposphere to form sulfuric and nitric acids, as well as other species, which are subsequently deposited at the earth s surface, either in precipitation (wet deposition) or in dry form (dry deposition). The contribution of organic acids has also been recognized recently (see Chapter 8). These oxidation and deposition processes can occur over relatively short distances from the primary pollutant sources or at distances of a fOOO km or more. Thus both short-range and long-range transport must be considered. 

Levy, H. et al. (1988) The long range transport of sulfur and nitrogen compounds. In The Eong Range Atmospheric Transport of Natural and Contaminant Substances (ed. Knap, A.H.). NATO ASI Series, Kluwer, Dordrecht. 

Since Galloway, Likens and Hawley ( ) have found that precipitation on Bermuda has significantly more excess SO , NO "", and H+ than more remote marine areas, Church and his colleagues ( ) have attributed these components to the long-range transport of sulfur and nitrogen precursors in the marine troposphere with the sulfuric-acid component dominating. 

Reiquam, H., Sulfur Simulated Long-Range Transport in the Atmos-... 

In a few exceptional cases, the long-range transport of a discrete cloud of a chemical has been tracked. Figure 4-27, portraying data obtained by a spectrometer on the Nimbus 7 satellite, shows a time sequence of a cloud of sulfur dioxide (S02) emitted from the Cerro Hudson volcano in Chile (Doiron et al., 1991). In this case, advection carried the cloud in an easterly direction around Earth, during which time the cloud became larger but more dilute as a result of dispersion and mass deposition onto Earth s surface. 

The version of this paper presented verbally at Kansas City dwelt at some length on an example drawn from an actual risk analysis performed by the author and his colleagues on a problem involving long range transport and possible human health effects from sulfur air pollution from coal-fired power plants. Interested readers can find details on this work elsewhere (12). 

In Beirut, the elemental composition study of coarse and fine particles showed that crustal elements like Si, Ca, K, Ti, Mn and Fe were prevalent in the coarse fraction while in the fine fraction S, Cu, Zn and Pb predominated. All-time high Ca concentration was due to the abundance of limestone rocks, rich in calcite, in Lebanon, and increased Cl levels correlated with marine air masses. In PM2.5, sulfur concentrations were more prominent in the summer due to the enhancement of photochemical reactions. Sources of sulfur were attributed to local, sea-water and long-range transport from Eastern Europe, with the latter being the most predominate. Anthropogenic elements like Cu and Zn were generated from worn brakes and tires in high traffic density areas. Spikes of Pb were directly linked to... 

Dust storms originating from the Saharan desert occur in autumn, winter and spring lead to the increase in coarse particles. In the summer, levels of fine particles are enhanced as a result of increased humidity, photochemically and induced secondary PM, and long-range transport of sulfur. 

In fact, long-range transportation of lignites, more than one-third of which consists of water, can more than triple the initial mine-mouth costs calculated on an energy basis. There may however be some trade-off in transportation costs if the low-rank coal is sufficiently low in sulfur which, in turn, means a lower cost in terms of stack gas cleanup (Nowacki, 1980). 

Rodhe, H. Cmtzen, P.J. Vanderpol, A., 1981 Formation of Sulfuric Acid in the Atmosphere During Long Range Transport , in Tellus, 33 132-141. 

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