above figure. Suppose the marginal benefit and the marginal cost curves of pollution abatement are normally shaped. Technological change that made it easier to produce in a "cleaner" fashion would cause curve (4) to shift out, increasing the optimal amount of pollution abatement. curve (3) to shift up, raising the marginal benefits and costs and reducing the amount of pollution abatement. curve (2) to shift out, increasing the optimal amount of pollution abatement. curve (1) to shift out, increasing the optimal amount of pollution abatement