Acid rain distribution

Acid deposition refers to the transport of acid constituents from the atmosphere to the earth s surface. This process includes dry deposition of SO2, NO2, HNO3, and particulate sulfate matter and wet deposition ("acid rain") to surfaces. This process is widespread and alters distribution of plant and aquatic species, soil composition, pH of water, and nutrient content, depending on the circumstances. 

High sulfur content in coal hinders the use of coal resources because sulfur dioxide emissions from utility and industrial boilers are a cause of acid rain. Thus, research into the nature of sulfur in coal is important for improving coal utilization. Geochemical studies of sulfur in coal provide information about the abundance, distribution, and speciation of sulfur in coal. Many of these properties are determined by geological environments and processes of coal formation. 

Kawamura and Kaplan [482] have described a sensitive method for measuring volatile acids (Ci-C7) in rain and fog samples using /j-bromophcnacyl esters and a high resolution capillary gas chromatograph employing fused silica columns. Experiments showed that the measured concentrations of volatile acids in spiked rain samples increased linearly in proportion to the concentrations of volatile acids added. Relative standard deviations were less than or equal to 18% for Q, C2 and C3 acids. The distributions of volatile acids in Los Angeles rain and fog samples are discussed. 

Dolan, E. Zhang, Y. Klarup, D. The Distribution Coefficient of Atrazine with Illinois Soils ALaboratory Exercise in Environmental Chemistry, /. Chem. Educ. 1998, 75, 1609-1610. Driscoll, J. A. Acid Rain Demonstration The Formation of Nitrogen Oxides as By-Products of High Temperature Flame in Connection with Internal Combustion Engines, /. Chem. Educ. 1997, 74, 1424-1425. 

Figure 2. Geographic distribution of acid rain and automobile corrosion in the United States.

Very little acidic material in the form of acid rain or fog droplets is expected to enter the indoor environment. The size distribution ranges from 0.5-50 /im diameter for fog droplets and from 200-5000 /im diameter for rain droplets (3 ). Most of the < 1 im diameter fog droplets that pass through standard filtration systems are likely to react with air duct walls before entering the indoor environment. The indoor surfaces are taken to be those surfaces that are not associated with the air handling system or leakage pathways. 

Figure 19.12 Formation of acidic precipitation. A complex interplay of human activities, atmospheric chemistry, and environmental distribution leads to acidic precipitation and its harmful effects. Car exhaust and electrical utility waste gases contain lower oxides of nitrogen and sulfur. These are oxidized in the atmosphere by O2 (or O3, not shown) to higher oxides (NO2, SO3), which react with moisture to form acidic rain, snow, and fog. In contact with acidic precipitation, many lakes become acidified, whereas limestone-bounded lakes form a carbonate buffer that prevents acidification.

Some domestic tap-water contains aluminium in high concentration, either naturally or because aluminium has been added as a flocculant in the purification process. Acid rain markedly increases the "natural" aluminium content of water. In chronic renal failure Mayor et al. (1981) have proposed that parathyroid hormone may contribute to the hyperaluminemia by increasing intestinal absorption and by influencing tissue distribution. The interrelations between parathyroid hormone and the homeostasis of aluminium and calcium remain to be defined. In aluminium poisoning the secretion rate of parathyroid hormone may be either reduced (Canata et al, 1983) or unchanged (Biswas et al., 1982). 

Wang Z, Akimoto H, Uno I (2002) Neutralization of soil aerosol and its impact on the distribution of acid rain over east Asia observations and model results. J Geophys Res 107 4389. doi 10.1029/2001JDOO1040... 

Plants were transferred to a special rain chamber and exposed to a simulated sulfate acid rain solution for one, 20 min period daily (except Tradescantia, 2 rainfalls daily). Descriptions of the chamber, the simulated rain solution, and the rain drop size distributions are given elsewhere (Evans, Gmur, and Da Costa, 1977). The pH levels of the simulated rain solutions were 5.7, 3.4, 3.1, 2.9, 2.7, 2.5, and 2.3. A plant was exposed to... 

Within cross-sections of Tradescantia there is a regular distribution of both trilaminar epidermal complexes and vascular bundles within the leaf mesophyll. The leaf mesophyll consists of parenchyma cells which are uniform in size and shape. Initial exposure to simulated acid rain of pH 2,7 resulted in the collapse of outer epidermal cells in some areas. Distortion of underlying epidermal cells in the trilaminar sites and disruption of upper mesophyll cells also occurred. The next stage of lesion development varied slightly among lesions. In most lesions, collapse of mesophyll cells near the adaxial epidermis was evident. However, cell hypertrophy was also observed in about 50% of all lesions. Hypertrophic cells attained a cell volume three times that of unaffected cells. Supportive cells near vascular bundles were usually partially collapsed at this stage. 

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