Carbon Monoxide Trend,Meteorology, and Three-Way Catalysts in Mexico City |
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| Authors: | Hector G. Riveros Alfredo Alba Pilar Ovalle Beatriz Silva Ernesto Sandoval |
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| Affiliation: | 1. Instituto de Física, Universidad Nacional Autónoma de México , México, D.F.;2. Departamento de Quimica Orgánica , Escuela Nacional de Ciencias Biológicas-Instituto Politécnico Nacional , México, D.F.;3. División Ciencias Biológicas y de la Salud , Universidad Autónoma Metropolitana-Iztapalapa , México, D.F.;4. Red Automática de Monitoreo Atmosférico , Comisión Ambiental Metropolitana DDF , México, D.F. |
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| Abstract: | ABSTRACT From the analysis of data of the Inspection/Maintenance (I/M) program, and of the long-term trend of ambient CO concentrations in Mexico City, it is inferred that three-way catalysts (TWCs) have a 45% efficiency, well below the expected 90% value. The most probable causes are sulfur poisoning, lead contamination, and ceramic breakage due to bumps and potholes on the streets. Also, we have found a ratio between the average daily peak value of atmospheric CO and gasoline consumption: (11 ± 1) ppbCO/MLm (million liters of gasoline per month) in 1988 decaying to (10 ±1) in 1991 for Mexico City before the introduction of TWCs. In addition, we found a correlation between the monthly averages of CO daily peak and meteorological variables, explaining most of the seasonal changes using only the intensity of the inversion layer and surface wind speed. |
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