Aerosol formation simulation in the context of extensive biofuel consumption and evolution in vehicle fleet within the Southeastern Region of Brazil

Abstract

The southeastern region of Brazil is the most populated area, covering the states of São Paulo, Minas Gerais, Rio de Janeiro, and Espiritu Santo. Over the years, these states have been affected by air pollution from local urban sources, transport among areas, and long-range transport. Despite many efforts to control primary emissions for two main sectors (industry and road transport), the air quality, in general, has improved for certain gases and particles, mainly the primary emissions. However, particles less than 2.5 µm (PM2.5) and surface ozone (O3) have yet to be controlled. Many studies agree that the road transport sector is the primary source of contribution and has a key role in the secondary aerosol formation processes. Consequently, higher concentrations of PM2.5 and O3 frequently remain above the limits recommended by the World Health Organization (WHO) guidelines.In Brazil, biofuels have been widely adopted in mobile sources because they have environmental benefits, such as reducing greenhouse gases and primary emission pollutants, compared with fossil fuels. However, a drawback is their role in the secondary formations of O3 and PM2.5. In this way, this one-year proposal project aims to study the formation of secondary aerosols in the atmosphere of the Southeastern region of Brazil. We also propose studying the impact of vehicle fleet evolution and extensive biofuel changes on air quality for the Metropolitan Area of São Paulo. The meteorological simulation will be done with the Weather Research and Forecasting (WRF) model, which will provide the meteorological data to the Models-3 Community Multiscale Air Quality Modeling System (CMAQ) model. Finalizing the project, we hope to get simulation results that will allow us to understand how the chemical reactions between pollutants from each emission sector affect the behavior of the fine particles and their secondary formation. Different scenarios of biofuel use and fleet evolution will be simulated, providing pros and cons concerning the air quality impacts of ultrafine particles. Changes in vehicular fleet and extensive biofuel consumption will be considered as a strategy to reduce emissions of pollutants and greenhouse gases in Southeastern Brazil.