IZABEL DA SILVA ANDRADE
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Artigo IPEN-doc 28827 Photochemical sensitivity to emissions and local meteorology in Bogotá, Santiago, and São Paulo2022 - SEGUEL, RODRIGO J.; GALLARDO, LAURA; OSSES, MAURICIO; ROJAS, NESTOR Y.; NOGUEIRA, THIAGO; MENARES, CAMILO; ANDRADE, MARIA de F.; BELALCAZAR, LUIS C.; CARRASCO, PAULA; ESKES, HENK; FLEMING, ZOE L.; HUNEEUS, NICOLAS; IBARRA-ESPINOSA, SERGIO; LANDULFO, EDUARDO; LEIVA, MANUEL; MANGONES, SONIA C.; MORAIS, FERNANDO G.; MOREIRA, GREGORI A.; PANTOJA, NICOLAS; PARRAGUEZ, SANTIAGO; ROJAS, JHOJAN P.; RONDANELLI, ROBERTO; ANDRADE, IZABEL da S.; TORO, RICHARD; YOSHIDA, ALEXANDRE C.This study delves into the photochemical atmospheric changes reported globally during the pandemic by analyzing the change in emissions from mobile sources and the contribution of local meteorology to ozone (O3) and particle formation in Bogotá (Colombia), Santiago (Chile), and São Paulo (Brazil). The impact of mobility reductions (50%–80%) produced by the early coronavirus-imposed lockdown was assessed through high-resolution vehicular emission inventories, surface measurements, aerosol optical depth and size, and satellite observations of tropospheric nitrogen dioxide (NO2) columns. A generalized additive model (GAM) technique was also used to separate the local meteorology and urban patterns from other drivers relevant for O3 and NO2 formation. Volatile organic compounds, nitrogen oxides (NOx), and fine particulate matter (PM2.5) decreased significantly due to motorized trip reductions. In situ nitrogen oxide median surface mixing ratios declined by 70%, 67%, and 67% in Bogotá, Santiago, and São Paulo, respectively. NO2 column medians from satellite observations decreased by 40%, 35%, and 47%, respectively, which was consistent with the changes in mobility and surface mixing ratio reductions of 34%, 25%, and 34%. However, the ambient NO2 to NOx ratio increased, denoting a shift of the O3 formation regime that led to a 51%, 36%, and 30% increase in the median O3 surface mixing ratios in the 3 respective cities. O3 showed high sensitivity to slight temperature changes during the pandemic lockdown period analyzed. However, the GAM results indicate that O3 increases were mainly caused by emission changes. The lockdown led to an increase in the median of the maximum daily 8-h average O3 of between 56% and 90% in these cities.Artigo IPEN-doc 27830 COVID-19 outbreak and air quality2021 - MOREIRA, GREGORI de A.; ANDRADE, IZABEL da S.; CACHEFFO, ALEXANDRE; YOSHIDA, ALEXANDRE C.; GOMES, ANTONIO A.; SILVA, JONATAN J. da; LOPES, FABIO J. da S.; LANDULFO, EDUARDOThis work compares variations in the concentrations and air quality indexes of the pollutants PM10, PM2.5, CO, and NO2, during the COVID-19 outbreak in São Paulo Municipality. Such comparisons considered the period of physical distancing (autumn) and the three first months of economic activities’ resumption (winter). The concentrations and indexes observed in 2020 were compared with their correspondent values measured in the three preceding years. Also, from a supervised machine learning algorithm, the correspondent 2020 expected values were predicted and used in these comparisons. In order to analyze the influence of meteorological conditions, the seasons studied were characterized using remote sensing and surface data. The pollutants predominantly emitted by the vehicle fleet (CO and NO2) had reductions in their concentrations, with values always below the predictions and good air quality indexes. However, the pollutants whose concentration is less dependent on automotive emissions (PM10 and PM2.5) had high proximity to the predictions during the autumn and lower values during some periods in winter. This reduction was not enough to avoid days with a moderate air quality index. The approximation of the average concentrations of PM10, PM2.5, and CO to the prediction, from the second-half August 2020, indicates the influence of activities’ resumption in air quality.Artigo IPEN-doc 27755 Influence of a biomass-burning event in PM2.5 concentration and air quality2021 - MOREIRA, GREGORI de A.; ANDRADE, IZABEL da S.; CACHEFFO, ALEXANDRE; LOPES, FABIO J. da S.; YOSHIDA, ALEXANDRE C.; GOMES, ANTONIO A.; SILVA, JONATAN J. da; LANDULFO, EDUARDOSevere biomass burning (BB) events have become increasingly common in South America in the last few years, mainly due to the high number of wildfires observed recently. Such incidents can negatively influence the air quality index associated with PM2.5 (particulate matter, which is harmful to human health). A study performed in the Metropolitan Area of São Paulo (MASP) took place on selected days of July 2019, evaluated the influence of a BB event on air quality. Use of combined remote sensing, a surface monitoring system and data modeling and enabled detection of the BB plume arrival (light detection and ranging (lidar) ratio of (50 ± 34) sr at 532 nm, and (72 ± 45) sr at 355 nm) and how it affected the Ångström exponent (>1.3), atmospheric optical depth (>0.7), PM2.5 concentrations (>25 µg.m−3), and air quality classification. The utilization of high-order statistical moments, obtained from elastic lidar, provided a new way to observe the entrainment process, allowing understanding of how a decoupled aerosol layer influences the local urban area. This new novel approach enables a lidar system to obtain the same results as a more complex set of instruments and verify how BB events contribute from air masses aloft towards near ground ones.