Application of Photochemical Trajectory Model to Evaluate OzoneFormation by Atmospheric Concentrations and Emissions of Propane andButane in Mexico City Metropolitan Zone

Abstract

Propane and butane have very low reaction velocity and are abundant in the atmosphere of the Mexico City Metropolitan Zone (MCMZ). An important contribution of those alkane to ozone formation is observed. The present work studies to what extent the atmospheric concentrations and emissions of propane and butane contribute to the ozone formation. This evaluation was realized with the trajectory photochemical model, emissions and meteorological data of the MCMZ. Propane contributes to the maximum of ozone concentration with 0.013 ppm (7.78% of the total) and butane with 0.027 ppm (15.34% of the total). The total contribution of propane and butane to ozone formation can be split, respectively, in 0.001 ppm and 0.013 ppm of ozone produced by emission, and 0.012 ppm, and 0.014 ppm of ozone produced by atmospheric concentrations from the initial conditions. Propane and butane have a total contribution to a maximum of ozone concentration of 23.12%. The maximum concentration of propane has a decrement of 68.62% in the photochemical modeling.