Using a 3-D Air Quality Model to Assess Ground-Level Ozone Production in S?o Paulo

摘要

In a joint study carried out by PETROBRAS R&D Center (CENPES) and S?o Paulo University Atmospheric Sciences Department (USP-IAG), tropospheric ozone formation and transport are being currently assessed in the Metropolitan Area of S?o Paulo (MASP) using the threedimensional Eulerian photochemical model CIT, developed by Carnegie Mellon University (CMU) and California Institute of Technology (Caltech). Given the limitations of the available information regarding updated and “real world” atmospheric emissions, both on the side of the industrial facilities located within the city airshed and also on the current running fleet in S?o Paulo, the base case to run CIT is built resorting to a step-by-step approach. The preliminary base case targets to portray MASP air quality status with emphasis on ozone, fitting the largest data base available for S?o Paulo, which refers to 2000. In that initial version the criteria pollutants (NO2, NO, CO, SO2 and ozone) ambient concentrations were forecasted and compared to the official air quality records (CETESB), thus covering the period from 22 to 24 August 2000, in which measured ozone concentrations exceeded the 1 hour NAAQS (80 ppb). An overall good fit of the model output as compared to the ambient monitoring data was reached. The next step is to add on the available information both on meteorological parameters, as well as emissions and air quality data, to build the more recent base-case for 2003. In that updated version, atmospheric characterization data regarding VOC speciation campaigns, carried out in MASP by CENPES and international environmental consultants (DGA, USA) in 2003/2004, are being incorporated, connecting kinetic modeling targeting O3 forecast to the current urban air quality status, described on the basis of its reactive precursors.