Acid precipitation sources

The controlled thermal decomposition of dry aromatic diazonium fluoborates to yield an aromatic fluoride, boron trifluoride and nitrogen is known as the Schiemann reaction. Most diazonium fluoborates have definite decomposition temperatures and the rates of decomposition, with few exceptions, are easily controlled. Another procedure for preparing the diazonium fluoborate is to diazotise in the presence of the fluoborate ion. Fluoboric acid may be the only acid present, thus acting as acid and source of fluoborate ion. The insoluble fluoborate separates as it is formed side reactions, such as phenol formation and coupling, are held at a minimum temperature control is not usually critical and the temperature may rise to about 20° without ill effect efficient stirring is, however, necessary since a continuously thickening precipitate is formed as the reaction proceeds. The modified procedure is illustrated by the preparation of -fluoroanisole ... 

The primary constituents to be measured are the pH of precipitation, sulfates, nitrates, ammonia, chloride ions, metal ions, phosphates, and specific conductivity. The pH measurements help to establish reliable longterm trends in patterns of acidic precipitation. The sulfate and nitrate information is related to anthropogenic sources where possible. The measurements of chloride ions, metal ions, and phosphates are related to sea spray and wind-blown dust sources. Specific conductivity is related to the level of dissolved salts in precipitation. 

Acid rain is actually a catchall phrase for any kind of acidic precipitation, including snow, sleet, mist, and fog. Acid rain begins when water comes into contact with sulfur and nitrogen oxides in the atmosphere. These oxides can come from natural sources such as volcanic emissions or decaying plants. But there are man-made sources as well, such as power plant and automobile emissions. In the United States, two-thirds of all the sulfur dioxide and one-fourth of the nitrogen oxides in the atmosphere are produced by coal-burning power plants. 

Since approximately half of the acid precipitation in eastern Canada has come from American sources, the Canada-United States Air Quality Agreement was signed... 

Making a Model Acid precipitation often falls to Earth hundreds of kilometers away from where the pollutant gases enter the atmosphere because the gases diffuse through the air and are carried by the wind. In this lab, you will model the formation of acid rain to observe how the damage caused by acid varies with the distance from the source of pollution. You also will observe another factor that affects the amount of damage caused by acid rain. 

Recent publications lead to the conclusion that ammonia contributes to the effects of acid precipitation. The main source of ammonia is animal production and regions with a high animal density are expected to have a high emission of ammonia. Because it is a volatile compound research workers in the field of odour measurement and odour control have the best knowledge and the best tools to study ammonia emissions. A proposal is made for the main goals of a research program. 

The inventory made by Buijsman in the Netherlands should be caracterised as a quite rough estimate. This is demonstrated by the assumptions on which he based his calculations. For instance he neglected the emission from stables for laek of reliable data. If the Government wants to reduce the acid precipitation, there will be paid attention to ammonia. As it is released from ground level sources reduction of ammonia emission has more effect on acid deposition in the region than in the case with S02 and NOx. 

Methane releases 25% less carbon dioxide per gram than coal, and it emits none of the oxides of nitrogen and sulfur that contribute to acid precipitation. Therefore, using methane in place of other fossil fuels is very desirable. Methane hydrates seem to be an ideal and plentiful pre-packaged source of natural gas. Estimates of the exact amount of methane stored in hydrates suggest there could be... 

Two Streptomyces strains, S. badius and S. viridosporus, were found to be able to grow on kraft lignin (In-dulin ATR) as sole carbon source. The resulting APPL (Acid Precipitable Polymeric Lignin) was characterized by FTIR and elemental analysis for C, H and N, and was found to contain proteins in addition to a relatively demethoxylated lignin component. The proteins were further characterized by amino acid analysis, while the lignin component was separated by solvent extraction and its molecular weight distribution determined by HPSEC. 

Crawford and co-workers were the first to study in detail the action of two streptomyces, S. badius 252 and S. viridosporus T7A, on lignocellulose from different sources. Their work led to the conclusion that the bacterial action on aqueous suspensions of these lignocellulosics resulted in the solubilization of lignin fragments which precipitate upon acidification Acid Precipitable Polymeric Lignin (APPL) (1-10). 

Emission of combustion gases, such as S02, NOx, and C02. These gases are potential sources of acid precipitation and might contribute to climate change (Hasanen et al. 1997). 

Acid precipitation resulting from sulfuric acid (and nitric acid) has the ability to significantly lower the pH. The reactions forming sulfuric acid in the atmosphere often take several days therefore acid precipitation can fall several hundred kilometers away from the pollution source. This has led to transnational negotiations and agreements in an attempt to control sulfur emissions, the precursor to acid precipitation. 

In some protein sources storage protein may be isolated from non-storage protein, or acid-precipitated proteins isolated from whey proteins. In the preparation of classical protein isolates by solubilization and acid precipitation, the amino acid make-up of the isolate differs from that of the extract. Consequently, consideration must be given to the amino acids chemically present in a refined protein. 

Zeng Y, Hopke PK (1989) A study of the sources of acid precipitation in Ontario, Canada. Atmos Environ 23 1499-1509... 

The Impact of North American Emissions on the Composition of the Atmosphere over the Western Atlantic Ocean. As part of WATOX-82 (August 1982) and WATOX-83 (January and February 1983), General Motors Research Laboratories operated air-monitoring sites on the Atlantic coast near Lewes, Delaware, and on the southwest coast of Bermuda, 1250 km to the southeast of the Delaware site. Their overall purpose was to study the transformations of the principal acid-precipitation precursors, NOx and SOx species, as they were transported under conditions not complicated by emissions from local sources. Three papers have resulted from this study (16. 17. 18). 

Globally, the oxides of nitrogen, NO (nitric oxide), NO2 (nitrogen oxide), and N2O (nitrous oxide), are key species involved in the chemistry of the troposphere and stratosphere. NO and N2O are produced mostly by microbial soil activity, whereas biomass burning is also an important source of NO. Nitric oxide is a species involved in the photochemical production of ozone in the troposphere, is involved in the chemical produaion of nitric acid, and is an important component of acid precipitation. Nitrous oxide plays a key role in stratospheric ozone depletion and is an important greenhouse gas, with a global warming potential more than 200 times that of CO2. 

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