The Impact of Biomass Burning on the Global Budget of Ozone and Ozone Precursors

Abstract

Biomass burning contributes significantly to the emissions of atmospheric trace gases such as carbon monoxide, nitrogen oxides, and hydrocarbons. For example, current evaluations estimate that about half of the surface emissions of carbon monoxide result from biomass burning. As these trace species act as ozone precursors, biomass burning plays an important role in the ozone budget of the troposphere. A three-dimensional chemical-transport model of the troposphere has been used to quantify the impact of biomass burning on the distribution of the main chemical tropospheric chemical species. The model results are compared with available observations, and the discussion focusses mostly on carbon monoxide, nitrogen oxides, and ozone global distributions. The contribution of biomass burning in each continent to the global budget of CO is evaluated. This contribution is compared to other emissions of carbon monoxide such as emissions related to industrial activities, soils and oceans, and net production of CO resulting from the oxidation of natural and anthropogenic hydrocarbons. The global and regional production of ozone resulting from these emissions is also discussed. The results of this study show that biomass burning plays a very important role in controlling the distributions of carbon monoxide, not only in the tropics, but also at mid- and high-latitudes. This emphasizes the need for accurate global estimations of the distribution of biomass burning as well as of emission factors for the study of past and future evolution ozone and other key chemical tropospheric species.