Implementation of the air quality model for the Metropolitan Region of São Paulo

Abstract

Pollution from gases and particles has been a difficult problem to tackle in complex urban regions, as is the case in the metropolitan regions of São Paulo. The factors that lead to poor air quality include gas emissions and particles, topography, meteorology, chemistry, and gas-particle conversion. Since the interactions between all these factors are complex, computational models were developed to simulate the production of pollution, and to understand these interactions. Technologically advanced countries have demonstrated the need to analyze the complex interactions between the chemistry and the meteorology which control the phenomena associated with atmospheric dispersion of pollutants. The appropriate methodology for this is the application of air quality models that include a description both of the chemical mechanisms and well as dispersion and transport. The Department of Atmospheric Sciences has considerable experience in the use of the CIT model, developed in the California Institute of Technology and Carnegie Mellon University. This model has been applied to the problem of the description of the formation of photochemical pollutants in São Paulo. The basic components of these modules are: a kinetic mechanism describing the chemical reactions; a description of the sources, with spatial and temporal distribution of the emissions; a meteorological description, including velocity and direction of the wind for each station, the vertical structure of the temperature and the intensity of the radiation. This model will be the host for the inclusion of the module of the formation of fine particles, which includes gas-particle conversion and growth by condensation and coagulation. This more complete model called CIT-AERO is being implemented in the Department of Atmospheric Sciences, in collaboration with the Carnegie Mellon University of Pittsburgh. (AU)