Modelling the formation of atmospheric aerosol particles in the Metropolitan Area of São Paulo

• Ano de defesa: 2018
• Autor(a) principal: Vela, Angel Liduvino Vara
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Biblioteca Digitais de Teses e Dissertações da USP
• Palavras-chave em Português: Aerossóis atmosféricos; Atmospheric aerosols; modelo WRF-Chem; Região Metropolitana de São Paulo; São Paulo Metropolitan Area; WRF-Chem model
• Link de acesso: http://www.teses.usp.br/teses/disponiveis/14/14133/tde-21052019-145224/

Nowadays, megacities all over the world are facing air quality issues, especially regarding the control of secondary pollutants such as tropospheric ozone (O3) but mainly fine particles (PM2.5 ; 2.5 m in diameter), as they have important impacts on both human health and climate change. Understanding the evolution of these particles in the atmosphere requires the description of emission sources as well as the physicochemical processes involved in their formation, growth and removal. In this study, the Weather Research and Forecasting with Chemistry (WRF-Chem) community model, a state-of-the-art coupled meteorology-chemistry modelling system, along with experimental data collected during the Narrowing the Uncertainties on Aerosol and Climate Change in São Paulo State (NUANCE-SPS, FAPESP thematic project) campaigns performed in 2012 and 2014, were used in order to examine the main properties of atmospheric aerosol particles over the Metropolitan Area of São Paulo (MASP), in southeastern Brazil, where changes in fuel blend and consumption in recent years have affected the evolution of pollutant concentrations. The combined application of aerosol data and WRF-Chem simulations made it possible to represent some of the most important aerosol properties such as particle number concentration (PNC) and cloud condensation nuclei (CCN) activation, besides allowing us to evaluate the contributions of anthropogenic and biomass burning sources to the PM2.5 loadings in the MASP. For instance, on-road vehicles have a potential to form new particles between 20 and 30 % in relation to the total PM2.5 mass, whereas biomass burning, on average, accounted for 824 % (515 g m3 ) of it. In addition, biomass burning accounted for up to 20 % of the baseline PNC- and CCN-weighted relative differences over the MASP (2300 cm3 and 1400 cm3 , respectively). The results indicate the potential importance of biomass burning sources for air quality in the MASP, and underscore the need for more accurate representations of aerosol emissions to reduce uncertainties in the model predictions.