Modeling Urban Ozone Formation in Rio de Janeiro, Brazil

摘要

PETROBRAS R&D Center (CENPES) and Rio de Janeiro Federal University (UFRJ) started outa joint project targeting reactivity assessment of Volatile Organic Compounds (VOC′s) in Rio deJaneiro, with special emphasis on the contribution of vehicular emissions to the local groundlevelozone production. Rio is the 2nd largest urban center in Brazil and the 2nd largest runningfleet in the country. The population living in the metropolitan area (RMRJ) is approximately11,3 million people, spread in 5645 km2, in which the current fleet (IBGE, 2004) of 2,2 millionvehicles accounts for roughly 77% of the total load of emissions regarding the main criteriapollutants (NOx, PM10, SO2 and CO), according to the records of the local environmental agent(FEEMA). Once approximately 80% of the current fleet is LDV (gasoline, with a growingmarket for CNG and the flex fuels) the major source of VOC′s to the atmosphere in Rio isattributable to vehicles, thus enforcing the need to accurately characterize both vehicularemissions and the ambient concentration distribution in terms of reactive VOC′s. In order to doso an empirical kinetic modeling package (OZIPR) was chosen to forecast the ozone formationpotential, based upon average conditions for RMRJ in several different scenarios. The initialbase case was built for the year 1999, with the ambient VOC speciation profile beingcharacterized from a screening campaign carried out by CENPES personnel and environmentalconsultants (DGA) in 1999 -2002. The average overall fit of the modeled results compared to themeasured ambient data was very good, as presented in the paper. The next step is to build anupdated base case with new sets of monitoring campaigns in 2003/2004 being incorporated,together with the updating the relevant meteorological parameters and the emissions inventory,both from vehicles and industrial facilities. Sensitivity analysis studies are presented anddiscussed.