GREGORI DE ARRUDA MOREIRA
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Artigo IPEN-doc 30391 Analyzing the influence of the planetary boundary layer height, ventilation coefficient, thermal inversions, and aerosol optical Depth on the concentration of PM2.5 in the city of São Paulo2024 - MOREIRA, GREGORI de A.; MARQUES, MARCIA T.A.; LOPES, FABIO J. da S.; ANDRADE, MARIA de F.; LANDULFO, EDUARDOCases of intense air pollution have been a recurring problem in most of urban centers in different regions of the world. Although actions to mitigate pollutant emissions are fundamental, it is also necessary to understand which factors can favor their dispersion process. In this scenario, this paper presents, for the first time, a long-term analysis of the Planetary Boundary Layer Height (PBLH), estimated through lidar and radiosounding data, Ventilation Coefficient (VC), Thermal Inversions (TI), and Aerosol Optical Depth (AOD), for the city of São Paulo, demonstrating how these variables are related with PM2.5 concentration. The analyzes showed that PBLH and VC have a seasonal cycle, with higher values in summer and lower ones in winter. Furthermore, PBLH is affected by one local factor, the sea-breeze, which reduces the concentration of aerosols in the late afternoon, resulting in an underestimated PBLH obtained from lidar data. Furthermore, from AERONET data, a predominance of Black Carbon and small particles was observed in all seasons, which are associated with the feedback effect observed in winter. Such effect attenuates the increase of PBLH and VC in cases of high concentrations of PM2.5. Finally, it was presented a Generalized Linear Model, which combines VC, AOD and TI information as input and can estimate the PM2.5 concentration with a R2 = 0.93.Artigo IPEN-doc 29945 Impact of extreme wildfires from the Brazilian Forests and sugarcane burning on the air quality of the biggest megacity on South America2023 - SOUTO-OLIVEIRA, CARLOS E.; MARQUES, MARCIA T.A.; NOGUEIRA, THIAGO; LOPES, FABIO J.S.; MEDEIROS, JOSE A.G.; MEDEIROS, ILCA M.M.A.; MOREIRA, GREGORI A.; DIAS, PEDRO L. da S.; LANDULFO, EDUARDO; ANDRADE, MARIA de F.Recently, extreme wildfires have damaged important ecosystems worldwide and have affected urban areas miles away due to long-range transport of smoke plumes. We performed a comprehensive analysis to clarify how smoke plumes from Pantanal and Amazon forests wildfires and sugarcane harvest burning also from interior of the state of São Paulo (ISSP) were transported and injected into the atmosphere of the Metropolitan Area of São Paulo (MASP), where they worsened air quality and increased greenhouse gas (GHG) levels. To classify event days, multiple biomass burning fingerprints as carbon isotopes, Lidar ratio and specific compounds ratios were combined with back trajectories modeling. During smoke plume event days in the MASP fine particulate matter concentrations exceeded the WHO standard (>25 μg m−3 ), at 99 % of the air quality monitoring stations, and peak CO2 excess were 100 % to 1178 % higher than non-event days. We demonstrated how external pollution events such as wildfires pose an additional challenge for cities, regarding public health threats associated to air quality, and reinforces the importance of GHG monitoring networks to track local and remote GHG emissions and sources in urban areas.Artigo IPEN-doc 29836 Analyzing the influence of vehicular traffic on the concentration of pollutants in the city of São Paulo2023 - MOREIRA, GREGORI de A.; CACHEFFO, ALEXANDRE; ANDRADE, IZABEL da S.; LOPES, FABIO JULIANO da S.; GOMES, ANTONIO A.; LANDULFO, EDUARDOThis study employs surface and remote sensing data jointly with deep learning techniques to examine the influence of vehicular traffic in the seasonal patterns of CO, NO2 , PM2.5, and PM10 concentrations in the São Paulo municipality, as the period of physical distancing (March 2020 to December 2021), due to SARS-CoV-2 pandemic and the resumption of activities, made it possible to observe significant variations in the flow of vehicles in the city of São Paulo. Firstly, an analysis of the planetary boundary layer height and ventilation coefficient was performed to identify the seasons’ patterns of pollution dispersion. Then, the variations (from 2018 to 2021) of the seasonal average values of air temperature, relative humidity, precipitation, and thermal inversion occurrence/position were compared to identify possible variations in the patterns of such variables that would justify (or deny) the occurrence of more favorable conditions for pollutants dispersion. However, no significant variations were found. Finally, the seasonal average concentrations of the previously mentioned pollutants were compared from 2018 to 2021, and the daily concentrations observed during the pandemic period were compared with a model based on an artificial neural network. Regarding the concentration of pollutants, the primarily sourced from vehicular traffic (CO and NO2 ) exhibited substantial variations, demonstrating an inverse relationship with the rate of social distancing. In addition, the measured concentrations deviated from the predictive model during periods of significant social isolation. Conversely, pollutants that were not primarily linked to vehicular sources (PM2.5 and PM10) exhibited minimal variation from 2018 to 2021; thus, their measured concentration remained consistent with the prediction model.