Sources and Sinks of Brominated Organics

Brominated organics are emitted into the atmosphere by a variety of natural and anthropogenic sources. Methyl bromide, CH3Br, is the most abundant organobromine compound emitted into the atmosphere, although others such as dibromomethane and chlorobromomethane may also contribute to a significant extent (e.g., see Kourtidis et al., 1996). Halons, especially CF2ClBr (Halon-1211) and CF3 Br (Halon-1301), are used as fire suppressants in situations where the use of water is not appropriate (e.g., around electronic equipment and on civilian aircraft; Freemantle, 1995). The numbering system for halons is in the following order: #C, #F, #C1, and #Br, where # indicates the number of each kind of atom in the molecule; when there is no chlorine in the compound, a zero is used in the third position. Thus C2F4Br2, for example, is Halon-2402 (O'Sullivan, 1989).

TABLE 12.6 Estimated Annual Global Emissions of Halon-1211 (CF2ClBr) and Halon-1301 (CF3Br) from 1963 to 1990" (in 106 kg/year)




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