The usefulness of air quality monitoring and air quality impact studies before the introduction of reformulated gasolines in developing countries. Mexico City, a real case study

Urban air pollution is a major environmental problem in several developing countries in the world. This phenomenon seems to be related to the growth of both the urban population in large cities and the number of old and poorly maintained car fleets. The expected rise of population in the next century in countries which suffer from lack of capital for air pollution control, means that there is a great potential for the worsening of the air quality. The worldwide promoted policy to phase out lead in gasolines has not proved to be an adequate option in improving the environmental quality. Mexico City Metropolitan Area (MCMA) represents a case in which the introduction of reformulated gasolines in an old car fleet has given as a result the reduction of the airborne lead levels but has worsened the ozone concentration of its urban atmosphere. This paper critically analyzes the chronological evolution of the ozone air pollution problem in MCMA after the successive occurrence of several changes in the formulation of low leaded and unleaded gasolines. It also presents evidences of the usefulness potential of air quality monitoring activities and air quality impact studies on the definition of realistic fuel reformulation policies of developing countries.