The MARKAL-Québec dynamic process model is used to simulate the reaction of the Québec energy and industrial sectors to the imposition of upper limits on the global emissions of NO_X and SO₂ acid gases into the atmosphere. Two economic scenarios are used, repectively for high and low demands for goods and services, and moderate prices of imported energy forms. Several SO₂ constraints are imposed in turn, as well as a single constraint on NO_X. In addition, a reference scenario with unconstrained emissions is also run, as well as a scenario where NO_X and SO₂ emissions are reduced by 10 and 50 percent repectively. The results are analyzed comparatively. The main technological and energy implications are presented by means of a series of figures showing the system's reaction to the imposed constraint. Particular attention is given to the copper smelting industry, to the refining of oil products, and to the changes occurring in the transportation sector. The impact of the emission constraints on the marginal cost of copper production is also discussed.