OZONE FORMATION IN BIOMASS BURNING PLUMES - INFLUENCE OF ATMOSPHERIC DILUTION

Biomass burning in the tropics contributes substantially to the emissi on of organic compounds and nitrogen oxides into the troposphere and h as an important impact on the global budget of ozone in the tropospher e. Since ozone formation is a nonlinear chemical process the rate of f ormation is also influenced by atmospheric dilution and,transport. Thi s paper addresses the production of ozone in a plume emerging from a b iomass burning site. Atmospheric mixing processes downwind the fire ar e expected to influence the total amount of ozone produced. A sensitiv ity study to assess the influence of dilution on the maximum ozone mix ing ratio and on the amount of ozone formed in the entire plume (exces s ozone) reveals that both quantities depend strongly on the time scal e and the final value of the dilution. Up to 70 % difference of the ex cess ozone as function of the characteristic time of the dilution was observed. Since many global models do not treat the early development of the plume with sufficient resolution in space and time a substantia l uncertainty of model predicted ozone formation from biomass burning plumes is to be expected.