A13D-3213:
Analysis of Ozone Transportation in Tlaxcala-Puebla Mexico Air Basin
Monday, 15 December 2014
Hugo Barrera-Huertas1, Ricardo Torres1, Luis Gerardo Ruiz-Suárez1, Jose Garcia2, Wilfrido Gutierrez2 and Alejandro Torres2, (1)UNAM National Autonomous University of Mexico, Mexico City, Mexico, (2)Universidad Nacional Autonoma de Mexico, Mexico City, Mexico
Abstract:
Preliminary results of an investigation conducted between March and April 2012 on the influence of air pollutants transport in the Puebla-Tlaxcala Valley airshed are presented. The campaign included ozone (O3), nitrogen dioxide (NO2) and meteorological variables monitoring at surface in Huaquechula, Chipilo and Amozoc rural sites, and measurements of O3 vertical profile O3 and meteorology in Chipilo. The synoptic conditions during the campaign showed dominance of "Norte" conditions favoring air masses circulation from Pacific Ocean crossing southern Mexican Plateau to the Gulf of Mexico that influences the establishment of evening southeasterly winds in the Puebla-Tlaxcala Valley. Wind roses and contaminants analysis in surface for O3 during entire campaign indicates that before noon the movement of air masses was dominated by runoff of Malinche toward the southeast and south of the valley; and in the afternoon a regional pattern of winds from southwest Valley prevails coming from Cuautla Valley and south of Morelos State. The analysis of three representative days of atmospheric circulation in the valley as well as anthropogenic diurnal activity, a rate of morning increase in O3 concentrations similar at all three sites was observed, even in the absence of precursors such as NO2 during some weekends. By analyzing and engage data from O3 vertical profile and surface meteorology data, we could infer that there are minimal ozone contributions from local sources, but important from regional origin, and even O3 entrainment in height brought to the surface when mixing layer is growing. The back trajectory analysis from Chipilo at noon indicates that could be additional contributions of O3 from both Cuautla Valley and other areas of pollutants emission such as Tula, (in the north of Mexico City), and that weekend effect with the occurrence of high O3 levels observed there extends to this region. Although interbasin exchange of pollutants between the Puebla-Tlaxcala Valley and Cuautla is confirmed, also was identified that O3 contribution in the free troposphere is important to sustaining high O3 values during the afternoon in Puebla. This implies that establishment of control strategies at regional level should be based on detailed studies of the influence of O3 seasonality in the free troposphere.
