The problem of biogenic emissions into the atmosphere is under discussion. The data on the effect of biomass burning on the chemical composition of the global atmosphere, as well as on gas-phase reactions of formation of atmospheric aerosol are analyzed. The principal attention is paid to consequences of biomass burning (forest, bush, and grass fires) in the tropics (Africa and South America) and, to a lesser degree, forest fires in mid-latitudes. The effect of biomass burning on the dynamics of tropospheric aerosol is considered separately. The influence of biomass burning on the global climate is briefly outlined as well.