A theoretical model of emission reductions is specified that accounts for voluntary and nonvoluntary behavior regarding the adherence to the Helsinki and Sofia Protocols, which mandated emission reductions for sulfur and nitrogen oxides (NO,), respectively. From the theoretical model, we derive an econometric specification for the demand for emission reductions that adjusts for the spatial dispersion of the pollutant. When tested for 26 European nations, the model and its forecasts perform reasonably well for sulfur cutbacks. Less satisfying results are obtained for NO A number of factors are identified that indicate that sulfur emissions are easier to control than those of NO