Author(s)

M. G. Vivanco & M. de Fátima Andrade

Abstract

Photochemical air pollution has become an important problem in the Metropolitan Area of Sao Paulo (MASP) over the past years. Approximately, 90% of the ozone precursors are emitted to the atmosphere by vehicular fleet. The estimation of precursors emissions, especially those from motor vehicles, is a rather complex task and it represents the major source of uncertainty. Ethanol represents about 32% of the fuel used in the light fleet vehicles. In this study, a validation of the nonmethane organic gases (NMOG) and x NO official emissions has been performed, using an observation-based approach. The x NO /CO and NMOG/CO ratios were calculated from earlymorning (0700 to 0800) ambient measurements taken in July and August, 1999. This approach assumes that early morning ambient concentrations of

Keywords