Economic and social projections indicate that during next several decades there will be major geographical redistribution of surface emissions of O3 precursors, such as NOx, CH4 and CO. A net decrease in their emissions from northern hemispheric mid-latitudes will be accompanied by substantial increases from the tropics. We have investigated a hypothetical scenario of currently underway transition of such emission patterns using a global two-dimensional photo-chemical model. With overall O3 precursor releases held constant, a simultaneous transfer of their emissions by 25% from the latitude belt 75 ¿N--35 ¿N to 5 ¿S--35 ¿N increases tropospheric oxidizing capacity such that the methane global lifetime and concentrations fall by more than 3%. Seasonally dependent changes in surface O3 concentrations are also calculated. In influencing OH concentration, redistribution of surface NOx emissions is 2-3 orders of magnitude more efficient per unit mass than CO emissions. Shifts in methane sources have insignificant effects on global photochemistry, but lead to a decrease in its interhemispheric gradient. ¿ 1998 American Geophysical Union