The American experience of negotiable permits to combat air pollution

Negotiable permits have been used in various fields, but the system in which they have seen greatest use is undoubtedly the American system of negotiable permits to fight acid rain. Since the 1970's, the United States have introduced elements of flexibility into their policy for fighting atmospheric pollution. These elements have included the family of negotiable permits. However, it was only in 1990 during the vote to amend the law on air cleanliness that a genuine market for the rights to emit SO2 was set up (taking effect on january 1. 1995). This article analyses this context in order to understand why and how such an instrument has been introduced, and goes on to present the results. (author)