The COVID-19 outbreak measures of lockdown have generated exceptional urban behavior conditions allowing the analysis of a unique scenario. We examined the atmospheric emissions in Buenos Aires, Argentina, based on urban and industrial continuous monitoring of NO2, PM10 and PM2.5, and NO2 (TROPOMI/Sentinel-5p) and AOD (MAIAC/MODIS, Aqua) satellite products, in addition with meteorological data. We considered the time intervals before and after the announcement of lockdown, including the same periods for 2019. The results showed that NO2 and PM10 concentrations fell by~30% and 44%, respectively, at urban stations during lockdown compared to 2019. An increase in PM at the industrial station (64% PM2.5 and 8% PM10) could be due to the contribution of industrial sources other than vehicle traffic. Also, we observed a reduction of the tropospheric NO2 column density mean by 54 % at urban stations, and AOD values decreased between 38 and 66 % during 2020. Concerning the spatial distribution, the tropospheric NO2 column showed a significant reduction of NO2 for the monthly mean in the metropolitan area at lockdown. Similarly, the AOD highest values had a greater extension for 2020 during the pre-lockdown monthly period. After the strict lockdown, concentration values increased steadily, particularly in ground-based measurements. Therefore, we were able to demonstrate the complementarity of ground-based and satellite data measurements of NO2 and aerosol to identify the effects of lockdown measures on the spatial and temporal variability of pollutants.

Space-based observations offer a unique opportunity to investigate the atmosphere and its changes over decadal time scales, particularly in regions lacking in situ and/or ground based observations. In this study, we investigate temporal and spatial variability of atmospheric particulate matter (aerosol) over the urban area of Córdoba (central Argentina) using over ten years (2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013)(2014)(2015) of

El 20 de abril de 2017 se instaló un nuevo fotómetro solar de la red AERONET-NASA en Pilar, provincia de Córdoba, en dependencias del Servicio Meteorológico Nacional, con el fin de medir la carga aerosólica de la región y sobre todo detectar los eventos de quema de biomasa que afectan el centro y norte del territorio, y que posteriormente-debido al transporte del viento-arriban a la provincia de Buenos Aires y La Pampa. Con la instalación de este nuevo instrumento, la red de fotómetros solares pasa a tener 7 equipos en el país, los cuales realizan sistemáticamente mediciones. Cabe destacar que el primer equipo se instaló en el CEILAP-UNIDEF (MINDEF-CONICET)-CITEDEF, el 17 de octubre de 1999 en Buenos Aires. En este trabajo se presentan los resultados obtenidos de un análisis estadístico efectuado sobre las mediciones de las 7 estaciones activas: CEILAP-BA, CEILAP-RG, CEILAP-Comodoro, CEILAP-Bariloche, CEILAP-Neuquén, Trelewy Pilar-Córdoba, con el propósito de determinar valores medios mensuales, tendencias de espesores ópticos de aerosoles, coeficiente de Ångstrӧm y clasificación del tipo de aerosol típico en suspensión en cada estación.

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