THE PROBLEM OF THE AIR POLLUTION IN MZMV
By : Mario Molina, Instituto Tecnologico de Massachusetts
Translated by: Juanira González Orta
Compared to other larges cities of the rest of the world, the problem of air pollution in Mexico city is particularly difficult to solve, due to we are surrounded by mountains, and we have frequently thermic inversions that can trap the pollution elements of the valley.
In this valley co-exist more than 18 thousands of inhabitants, more than 3 thousands of vehicles, and around 35,000 industries and service places. That join to the activities that consume a superior volume of 44 thousands of litters of fuel per day, and the consequence of the thousands of tons of pollution elements emissions, this last ones chemically react in the atmosphere to form another various contaminants, which also chemically react and form another kind ok pollution element that most of the times are even more harmful to the health.
Some aspects of this problem have been attacked by the politics and practiced actions in the 90's. in those years, there were achieve substantial reductions in the concentrations of Pb, SO2 and CO, although it wasn't a big help with the concentrations of ozone, NO2 and particles.
Now days, the air quality norms that are exceeded most frequently in the valley are the ozone and the one of particles PM10, meanwhile the rest of the polluting agents are almost always in levels within the norm. In the ozone's case the norm of one hour is exceeded more of the 80% of the days and this has been happening year after year since 1988. The ozone's tip concentrations, near the 300 ppb, are comparable to the ones the city of the Angels had during the 70´s, and are above the observed ones at the present time in any city of the United States. Regarding the to PM10, the norm for 24 hours exceeded in more than the 40% of the days in some years (although in the last year the norm was exceeded under the 10% of the days). On the other hand, the annual average concentration have surpassed the maximum limits established by the norms since 1995; inclusive in Xalostoc have been reached levels two or three times above the annual norm. In consequence the ozone and the particles are the pollution elements that affects the most in Mexico cityand are the ones that deserves immediate attention.