Uma análise da emissão de poluentes dos modais de transporte urbano brasileiro à luz do metabolismo social

Abstract

The urbanization process, responsible for the motorization of the Brazilian population, causes large emissions of pollutants into the atmosphere. In huge urban centers it is caused, in part, by urban transportation modes. In this dissertation, the analysis of the emission of these pollutants will have as theoretical basis the Ecological Economics, through the relationship of social systems with natural systems: the Social Metabolism that consists in the study of the flows of energy and matter removed, transformed and returned to nature. Within the metabolic flow, Excretion is an uncontrolled process, harmful and dependent on all processes (Appropriation, Transformation, Distribution and Consumption), becoming one of the most important factors for the imbalance of ecosystems on our planet. The emission of atmospheric pollutants from mobile sources is analyzed by means of modals: subway, bus, car, motorcycle, and it is possible to compare the Excretion process of each modal of Brazilian urban transport. For this, each modal is described, the legal framework about the air quality in Brazil and the atmospheric pollutants considered at local and global levels. The results show that the level of excretion per person per kilometer (epkm) of the individual motorized modes is 36.9 times higher if compared to the public, as is the case of cars compared to the subway. It is concluded that one way to reduce the level of excretion caused by the social metabolism of Brazilian urban transport is to encourage the use and improvement of nonmotorized modals in addition to public ones, with high occupancy capacity and low emission of local air pollutants and greenhouse gases.