Composition of Smoke from North American Boreal Forest Fires

Abstract

The release of gaseous and aerosol products into the atmosphere during controlled and naturally occurring vegetation fires is exerting a global influence on both atmospheric chemistry and climate (Goldammer and Crutzen 1993). In many cases, assessments of the impacts from biomass burning are not sufficiently quantitative to support serious environmental policy decisions or legislation that might lead to immediate economic and social consequences. Although large amounts of burning occur naturally, most burning in the last century has been the result of human activities (Andreae 1991). Burning for agricultural purposes is extensively practiced worldwide. Fire is used commonly in deforestation and in land management. Substantial amounts of environmentally important gases and aerosols are released into the atmosphere during combustion, and biomass fires may be modifiers of longer-term biogenic processes involved in the interchange of gases between the atmosphere and biosphere (Levine et al. 1990; Zepp 1988). Fires are also shaping the present and future population and structure of vegetation (Richter et al. 1982), and may be among the key proximate factors determining how terrestrial vegetation responds to future climate change (Walker 1991; Clark and Reid 1993).