The negative effects on human health, along with the fatalities caused by the new coronavirus, have led governments worldwide to take strict measures. However, a reduction in air pollution has been found in many regions on a global scale. This study is focused on how the COVID-19 pandemic is impacting on the air quality in Ecuador, one of the most alarming cases of COVID-19 contagion in Latin America, occupying the first place as regards deaths per capita. The spatio-temporal variations in NO
2
concentrations in 12 highly populated cities were evaluated by comparing the NO
2
tropospheric concentrations before (2019) and after (2020) the COVID-19 lockdown. The atmospheric data was collected from the TROPOMI on the Sentinel-5P satellite of the European Space Agency. A reduction in NO
2
concentrations (−13%) was observed as a consequence of the COVID-19 lockdown in Ecuador. However, this reduction occurred to the greatest extent in the cases of Guayaquil (−23.4%) and Quito (−22.4%), the two most highly populated cities. Linking NO
2
levels to confirmed cases/deaths of COVID-19, a strong correlation between air NO
2
concentrations and the cases/mortality caused by coronavirus (
r
= 0.91; p<0.001) was observed. This work highlights the crucial role played by air quality as regards human health.
Uno de los principales problemas ambientales atribuidos al uso de la tierra en la cuenca del río Chichiriviche (estado Vargas, Venezuela), está vinculado con la actividad agrícola que, origina condiciones para la activación de procesos erosivos en el suelo, frente al impacto de la lluvia. Bajo este contexto, se analizaron el potencial erosivo y las intensidades extremas de las precipitaciones, como indicadores de erosividad en la cuenca montañosa del río Chichiriviche. Se analizaron la distribución espacio-temporal de las precipitaciones, la frecuencia de los eventos extremos de las intensidades y se estimaron los Índices de Fournier Anual, Modificado de Fournier, Concentración de las Precipitaciones, Erosividad Total y Potencial Erosivo de las Lluvias. La distribución espacial de las lluvias está controlada principalmente por la altitud; su régimen anual se caracteriza por una mayor concentración de precipitaciones a finales de año. Las intensidades máximas oscilaron entre 56,43 mm/h y 81,95 mm/h para eventos de 1 hora de duración y 100 años de período de retorno. Los índices estimados, indicaron bajo a moderado potencial erosivo de las lluvias. La ocurrencia de procesos erosivos en el área estudiada, está relacionada con la intensidad de las precipitaciones extraordinarias como eventos puntuales aislados.
<p>Con base en eventos registrados de movimientos en masa y crecidas, ocurridos en la cuenca del río San Julián y activados por lluvias extraordinarias, se realizó una caracterización hidroclimatológica y morfométrica del sistema, como aporte a la evaluación de la amenaza hidrogeomorfológica. En la metodología se consideró la fotointerpretación geomorfológica, las mediciones y los cálculos de parámetros morfométricos, así como la estimación del tiempo de concentración, la caracterización del régimen pluviométrico y el análisis de eventos extremos de precipitación. La cuenca analizada es un sistema cuyas respuestas hidrológicas están determinadas por sus características morfométricas, lo cual se evidencia en su corto tiempo de concentración, debido a su ubicación en un ambiente montañoso, y a las magnitudes de los eventos extremos de precipitación.</p>
The activation of erosive processes on the slopes of the drainage catchments in the Ecuadorian coastal region represents a serious environmental problem that results in a loss of soil resources with the consequent reduction in agricultural productivity, an increasing lack of areas with vegetation, and decreased water quality. These issues increase, among other things, the probability of flooding. The purpose of this research is to zone soil erosion risk in the Manabí province, which is located on the Ecuadorian coast. The methodology is supported by the employment of Geographic Information Technologies (GIT) in order to access and process information of interest, such as: precipitation data with which to calculate the R Factor of the Universal Soil Loss Equation (USLE); topography, which was employed to create a slope map from the Digital Elevation Model (DEM) ASTER; vegetation cover, by applying the Standard Difference Vegetation Index (NDVI); land use, through the interpretation of orthophotos and a field survey; and infiltration capacity, obtained by considering the texture of the soil. The factors were combined by means a weighted relationship (map algebra) and exploiting the potential of software for the design of Geographic Information Systems (GIS). The results indicate the presence of soils with little or without vegetal protection, in areas with steep slopes, moderate rainfall and extensive farming activities. These characteristics determine conditions of high soil erodability, and propitiate the triggering of erosive processes. This scenario shows the need for autonomous governments to implement policies, strategies and actions so as to promote the strengthening of institutional and community capacities that will promote environmental sustainability.
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