COVID-19 pandemic impacted differently air quality in Latin American cities

Abstract This research explores the spatial and temporal variations of nitrogen dioxide (NO₂), sulphur dioxide (SO₂), and ozone (O₃) levels in four Latin American cities, namely Mexico City, Santiago de Chile, Lima, and the Metropolitan District of Quito, utilizing Sentinel-5P satellite data alongside ground-based monitoring stations. The period covers pre-lockdown, lockdown, and post-lockdown phases of the COVID-19 pandemic, providing insights into pollutant behaviour across different levels of human activity. Findings show notable spatial variability in pollutant levels, with Santiago de Chile repeatedly presenting the highest concentrations of NO₂ and SO₂, linked to urban development and local weather patterns, whereas Quito showed the lowest levels. The lockdowns typically resulted in decreased NO₂ concentrations, yet their effects on SO₂ and O₃ levels were inconsistent, highlighting the complexity of pollutant interactions. The research confirms that satellite data serves as an affordable addition to conventional monitoring, especially in areas with limited resources. These results emphasize the necessity for customized, city-oriented strategies to reduce urban air pollution and safeguard public health.