1. Introduction
Since the adoption in 1999 of the Gothenburg Protocol to abate acid- ification, eutrophication and ground-level ozone, the Government of Spain has been continuously designing and implementing regulations to abate general air pollution level and comply with its international ob- ligations as a signing party. Moreover, as a Member State of the European Union, Spain is legally-bound by the European regulatory framework on air and environmental quality which has required com- plementary policy efforts across several years. In general the policy making process for air quality control in Spain has not been a simple one, too often conditioned by conflicts between national and regional