Normes, taxes et pollution diffuse aux nitrates

Based upon a critical review of various works about nitrate NPS pollution, we show that in the debate opposing price vs. quantity instruments to regulate pollution, it is possible to refine ? and even more to go past ? the measures which fail to reduce pollution, but at a significantly higher public cost, to be balanced with the expected private cost savings. First of all, we shall see that the employment of standards on inputs is not always very expensive for farmers regarding the cost associated with a tax on fertilizers, but the public costs that these standards need to support are very high and may explain, for a large part, why some European countries preferred to use this later. Nevertheless, we will see that tax on fertilizers is partly unfair in so far as the farmers continue to pay it on optimal unit of fertilizers, and so at such a point that tax rates remain too small to have any significant impact on fertilizer consumption and then nitrates pollution. Finally, according to the idea that efficiency and equity would remain inseparable for any new design or instrument ? in order to increase its social and political acceptability ?, we analyse some refined measures, keeping this ideal in mind. We then see that these ambitious refinements may probably be very costly in public funds. But may be it is the price to consent to definitely reduce NPS pollution.