Mexico City is inhabited by more than 15 million people, driving about 2.7 million motor vehicles. The air pollution from its intense traffic is aggravated by its topographical and meteorological conditions. In 1991, it was estimated that 25% of Mexico's vehicles were generating 47% of its carbon monoxide emissions and 62% of its hydrocarbon emissions. In this situation, it was essential to adopt a new approach, to reverse the trend of rising vehicle-generated pollution. The PICCA (Prevention and Control of Atmospheric Pollution in the Mexico City Valley Area) strategy was prepared, and a Metropolitan Commission was set up to implement it. PICCA's key policies for reducing vehicle pollution are: (1) producing fuels to environmental standards; (2) improving and expanding public transport, and discouraging the use of private cars; and (3) introducing systems and measures to monitor polluting exhaust emissions. During the last five years, the composition of the fuels used in Mexico City has changed radically; as a result, there have been significant falls in the concentrations of lead, sulphur, and carbon monoxide especially. 85% of the daily journeys in Mexico City are made using public transport, especially minibuses, urban buses, and the metro. Many measures have been introduced to monitor and control vehicle emissions.
Abstract