Atmospheric boundary layer height calculation in México City derived by applying the individual eulerian box model

Abstract

Ethylene emissions are characteristic of primary exhalations of vehicular combustion processes. Their reac­tion with hydroxyl radicals in the presence of solar UV radiation promotes the production of ozone. Previ­ously, our research group reported the measurement of real-time profiles of ethylene concentration (EC) in the atmosphere of the Metropolitan Zone of México City (MZMC) by means of laser photoacoustic system, based on 12C16O2. In this work, we applied the Euler box photochemical model to fit the time-dependent experimental ethylene concentration profiles recorded in the working week February 19-23, 2001. Those profiles allowed us to calculate the continuous variation of the atmospheric boundary layer (HABL) between 5:00 and 21:00 h, under stable atmospheric conditions. From the fitting function C(t), we identified the corresponding HABL temporal curves for the entire week of the campaign. Also, the emission ethylene rate general profile q(t) was determined, presenting three maximum peaks. The values of the HABL height ranged between 169 and 357 m in the morning and between 2700 and 3869 m in the afternoon. The Euler model, applied under atmospheric stable conditions, predicts the shifts of the three q(t) maximum center peaks depending on rush hours, Euler box volume, and –OH and ethene reactions.