A evolução da qualidade do ar e a relação com a adoção de políticas públicas para controle das emissões veiculares na megacidade do Rio de Janeiro

Abstract

Air quality in Brazilian metropolitan regions has become an increasing challenge due to its impacts on public health, the environment, and urban sustainability. In this context, this dissertation analyzes the evolution of air quality recorded over the last 25 years, between 1998 and 2023, in the Metropolitan Area of Rio de Janeiro (MARJ), focusing on the impacts of the implementation of public policies for vehicular emissions control.. To this end, data from 26 automatic monitoring stations of the State Environmental Institute (INEA) were used, comprising time series of the main atmospheric pollutants (CO, O₃, NO₂, SO₂, PM₁₀, and PM₂.₅). The analysis considered temporal variability, seasonal patterns, spatial distribution of concentrations, and the frequency of exceedances of the standards established by CONAMA Resolution No. 491/2018 and the World Health Organization (2021) guidelines. The methodology included statistical treatment of historical series, identification of extreme events, and integrated analysis between observed concentrations and estimates of vehicular emissions, based on fleet data, fuel consumption, and average emission factors associated with the phases of PROCONVE. The results indicate a consistent reduction in the concentrations of primary pollutants over the analyzed period. CO showed a reduction of approximately 57.9% between 2002 and 2023, with mean values decreasing from about 1.9 ppm to less than 0.8 ppm. NO₂ also showed a significant decline, particularly after 2012, associated with the adoption of vehicle emission control technologies capable of reducing NOx emissions by up to 60% in heavy-duty vehicles. SO₂ showed a marked decrease since the 2000s, in response to the reduction of sulfur content in fuels, from approximately 2,000 ppm in the 1990s to around 10 ppm in the 2010s. In contrast, particulate matter exhibited a more critical behavior. PM₁₀ showed a high frequency of exceedances of the daily standard (100 μg/m³), often exceeding 100 days per year at several monitoring stations. PM₂.₅ presented an even more concerning scenario, with records exceeding 300 days per year above reference values in some locations, indicating chronic population exposure. Ozone (O₃), in turn, remained at elevated levels with recurrent exceedances throughout the historical series, with no clear decreasing trend, reflecting the complexity associated with secondary pollutant formation. From a spatial perspective, critical areas were identified, particularly in Baixada Fluminense, with emphasis on the municipality of Duque de Caxias, characterized by a high frequency of exceedances associated with the combination of vehicular and industrial sources and unfavorable socio-environmental conditions. The comparison between absolute and relative emissions indicates that, although technological advances associated with public policies have significantly reduced the average emission potential of the fleet, the growth in the number of vehicles tends to offset reductions in total emitted loads. This study reinforces the importance of the continuity and improvement of environmental public policies, the integration between technological control and urban planning, and the strengthening of air quality monitoring networks as key instruments to promote sustained improvements in air quality and public health in the RMRJ.