CO2 concentrations in the highly polluted atmosphere of Mexico City

Abstract

Measurements of CO₂ concentrations in the atmosphere of Mexico City were carried out through the years 1981-1982, during daylight hours. The results indicate that 82 of the CO₂ levels were above 330 ppmv, which is the reported approximate atmospheric background. During daylight hours CO₂ concentrations show three maxima: the first between 9:30 and 10:30 h, the second between 12:00 h and 13:00 and the third between 15:00 and 16:00 h local time. The peaks coincide with the rush hours in the city. The annual curves of CO₂ show a seasonal variation with low values during the winter and a maximum in spring, the lowest values corresponding to the middle of the rainy season. Since natural sources during the daylight hours are probably negligible, the applicability of CO₂ data as an indicator of air pollution in Mexico seems to be feasible.