Bromide in the atmosphere

Robbins DE. 1976. Photodissociation of methyl chloride and methyl bromide in the atmosphere. Geophys Res Lett 3 213-216. 

Butler JH, Rodriguez JM (1996) Methyl Bromide in the Atmosphere. In Bell CH, Price N, Chakrabarti B (eds) The Methyl Bromide Issue. Wiley, Chichester, UK, p 27... 

Robbins, D.E. (1976) Photodissociation of methyl chloride and methyl bromide in the atmosphere. Geophys. Res. Letter 3, 213-216. Robbins, G.A., Wang, S., Stuart, J.D. (1993) Using the static headspace method to determine Henry s law constants. Anal. Chem. 65, 3113-3118. 

Yvon-Lewis, S., Methyl bromide in the atmosphere and ocean, IGAClivities Newsletter, International Global Atmospheric Chemistry Project, Issue 19, Ian. 9-12, 2000. 

Bond EJ, Dumas T. 1987. Concentrations of methyl bromide inside flour mills and in the atmosphere around the mills during and after fumigation. Proc Entomol Soc Ont 118 1-6. 

Anticipated products from the reaction of ethylene dibromide with ozone or OH radicals in the atmosphere are bromoacetaldehyde, formaldehyde, bromoformaldehyde, and bromide radicals (Cupitt, 1980). 

The detection and monitoring of bromine is important in various fields of application. In industrial processes, bromine is employed, for example, for the desulfurization of flue gas and an on-line detector enables the process to be optimized. The presence of bromine in the atmosphere has been implicated in processes such as ozone depletion, [145] and devices for monitoring the release of bromine and bromine derivatives are desirable. Bromide monitoring is of interest in industrial contexts, photographic developers, environmental, and in medical samples. 

Various other workers have reported on the determination of volatile organic compounds in soils [186,187] and landfill soils [188]. Soil fumigants such as methyl bromide have also been determined by this technique [189]. Trifluoroacetic acid is a breakdown product of hydrofluorocarbons and hydrochlorofluorocarbon refrigerant products in the atmosphere and, as such, due to the known toxicity of trifluoroacetic acid, it is important to be able to determine it in the atmosphere, water and in soil from an environmental point of view [190]. In this method the trifluoroacetic acid is extracted from the soil sample by sulfuric acid and methanol, which is then followed by the derivatisation of it to the methyl ester. The highly volatile methyl ester is then analysed with a recovery of 87% using headspace gas chromatography. Levels of trifluoroacetic acid in soil down to 0.2 ng/g can be determined by the procedure. 

Hydrolysis can explain the attenuation of contaminant plumes in aquifers where the ratio of rate constant to flow rate is sufficiently high. Thus 1,1,1-trichloroethane (TCA) has been observed to disappear from a mixed halocarbon plume over time, while trichlo-roethene and its biodegradation product 1,2-dichloroethene persist. The hydrolytic loss of organophosphate pesticides in sea water, as determined from both laboratory and field studies, suggests that these compounds will not be long-term contaminants despite runoff into streams and, eventually, the sea (Cotham and Bidleman, 1989). The oceans also can provide a major sink for atmospheric species ranging from carbon tetrachloride to methyl bromide. Loss of methyl bromide in the oceans by a combination of hydrolysis... 

For some pesticide compounds, such as dini-troaniline herbicides (Weber, 1990), phototransformation occurs primarily in the vapor phase, rather than in the dissolved or sorbed phases. Perhaps the most environmentally significant pesticide phototransformation in the atmosphere, however, is the photolysis of the fumigant methyl bromide, since the bromine radicals created by this reaction are 50 times more efficient than chlorine radicals in destroying stratospheric ozone (Jeffers and Wolfe, 1996). Detailed summaries of the rates and pathways of phototransformation of pesticides and other organic compounds in natural systems, and discussions of the physical and chemical factors that influence these reactions, have been presented elsewhere (e.g., Zepp et al, 1984 Mill and Mabey, 1985 Harris, 1990b). 

Okamoto and Attarwala [159] brought an improvement to the reaction of Severin, by adding a cationic surfactant (as a phase transfer catalyst) to the reaction medium. They examined the reduction of unsymmetrically substituted -2,4,5- and 2,3,4-trinitrotoluenes by sodium borohydride in methylene dichloride at 23-24 C in the atmosphere of nitrogen in the presence of ethylhexadecyl-dimethylammonium bromide. 

Ethyl bromide is likely to be a vapor in the atmosphere where it may be degraded by reaction with... 

In the atmosphere, particulate bound mercury constitutes only 2% of total mercury in the air and has normally been found to be less than 0.1 ngm in regions unaffected by local sources. Some other mercury compounds, which may exist in the atmosphere, are mercuric chloride, mercuric bromide, mercuric hydroxide, mercuric sulfide, and mercuric cyanide. The rest is elemental mercury in the gaseous phase. In remote areas over the Atlantic and Pacific oceans, mercury bound to particulate matter concentrations are generally at or below the picogram per cubic meter level. 

Vinyl bromide s production and use as a flame retardant for acrylic fiber may result in its release to the environment through various waste streams. It may form in air as a degradation product of 1,2-di-bromoethane. Vinyl bromide was detected in fuma-roles and lava gas from volcanoes. If released into air, with a vapor pressure of 1030 mmHg at 25°C, vinyl bromide will exist in the gas phase. Gas-phase vinyl bromide will be degraded in the atmosphere by... 

Leaded gasoline, originally developed to decrease pollution, is now banned because the lead(II) bromide, PbBr2, emitted when it burns decomposes in the atmosphere into two serious pollutants, lead and bromine. The equation for this reaction is below. Determine the oxidation number for each atom in the equation and identify whether the reaction is a redox reaction or not. If the reaction is redox, identify what is oxidized and what is reduced. 

The possibility that the depletion of chloride in the marine aerosol is due to fractionation during the formation of sea-salt particles by bursting bubbles can be discounted. Laboratory studies of Chesselet et al (1972b) and Wilkness and Bressan (1972) showed no deviation of the Cl /Na+ mass ratio from seawater in the bubble-produced sea-salt particles. It may be mentioned in passing that bromide in marine aerosols shows a deficit similar to chloride, whereas iodide is present in excess. The latter observation is attributed to both chemical enrichment at the sea s surface and scavenging of iodine from the gas phase. A portion of iodine is released from the ocean as methyl iodide, which in the atmosphere is subject to photodecomposition and thereby provides a source of scavengable iodine. The process has been reviewed by Duce and Hoffman (1976). In continental aerosols, chloride and bromide are partly remnants of sea salt, but there exists also a contribution from the gas phase. 

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