Importance of biomass burning in the atmospheric budgets of nitrogen-containing gases

Abstract

BIOMASS burning is a primary source of many trace substances that are important in atmospheric chemistry^1–6. More than 80% of the world's biomass burning takes place in the tropics³ as a result of savanna fires, forest-clearing activity, and the burning of agricultural waste and wood. Here we report results from laboratory studies on the emission of nitrogen-containing compounds from the burning of dry vegetation. We find that the emission rates of NO_X, HCN and CH₃CN are sufficient to contribute significantly to the global atmospheric budget of the compounds. Furthermore, possibly up to half of the biomass nitrogen can be converted to molecular nitrogen, N₂, leading to an estimated annual loss of 12–28 x 10¹²g of biomass nitrogen ('pyrodenitrification'), equal to ∼9–20% of the estimated global rate of terrestrial nitrogen fixation.