Vol. 23, issue 06, article # 1

Abstract:

Siberian boreal forest fires burn at 10-14 million hectares annually. Burning of forest biomass results in the emission into the atmosphere of large amounts (300-500 million tons annually) of both gaseous combustion products and solid/liquid smoke particu-lates. Direct measurements of smoke emissions conducted in several natural fire experiments at a taiga territory of Krasnoyarsk re-gion in 2000-2009 show that a total amount of particulate emission from the fire is estimated to be 0.2-1 t/ha. These values repre-sent 1-7% of the total biomass consumed during a typical forest fire in Siberia (15-30 t/ha); the rest of 93-99% of the burned bio-mass are the gaseous combustion products. The data on the dispersal characteristics of particulate smokes, averaged over 16 natural fire experiments in 2007-2009, show that (89±8)% of the total particulate matter are in the particles with aerodynamical diameters of less than 3 mm, (7±6)% are in the particles of 3-5 mm, the rest 5-10% - in the particulates larger than 7 mm. Morphological structures of the smoke particulates indicate that the primary submicron particles are formed due to condensation of the unconsumed organic vapors over a combustion zone, followed by their coagulation into particles of 1-3 mm. A trace-element composition of the fine dispersal fraction is demonstrated to be used for discrimination between the sources of these elements.

Keywords:

smoke particulates, smoke emission, biomass burning, forest fire, dispersal distribution, chemical trace elements