Spatiotemporal Assessment of Tropospheric Nitrogen Dioxide Changes During COVID-19 Lockdowns Using Cloud-Based Remote Sensing: Evidence from Central America.
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| Title: | Spatiotemporal Assessment of Tropospheric Nitrogen Dioxide Changes During COVID-19 Lockdowns Using Cloud-Based Remote Sensing: Evidence from Central America. |
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| Authors: | Caal Suc, Nestor Erick Anibal1,2 (AUTHOR) nestorcaalsuc@profesor.usac.edu.gt, Pacheco Gil, Henry Antonio2,3 (AUTHOR), Godoy Morales, Martha Ruthilia1,3 (AUTHOR), Lobos Morales, Víctor Manuel1,4 (AUTHOR), López Bautista, Amado Adalberto4,5 (AUTHOR), Rivas, Carlos A.1,5 (AUTHOR), Navarro-Cerrillo, Rafael María2 (AUTHOR) |
| Source: | Remote Sensing. Jun2026, Vol. 18 Issue 11, p1850. 15p. |
| Subjects: | Satellite-based remote sensing, Atmospheric nitrogen dioxide, Stay-at-home orders, Remote sensing, Geospatial data, Air quality, Artificial satellites |
| Geographic Terms: | Central America, El Salvador, Guatemala (Guatemala), Honduras |
| Abstract: | Highlights: What are the main findings? Satellite-based observations revealed noticeable spatiotemporal variability in tropospheric NO2 concentrations across Central America during the COVID-19 period, with stronger negative variations observed in highly urbanized departments of Guatemala, El Salvador, and Honduras. The integration of Sentinel-5P TROPOMI data within Google Earth Engine enabled a consistent regional-scale assessment of atmospheric variability, highlighting heterogeneous responses among countries with different mobility restriction measures. What are the implications of the main findings? The results demonstrate the potential of cloud-based Earth observation platforms for atmospheric monitoring and air quality assessment in tropical regions characterized by limited ground-based monitoring networks. The observed regional and subnational variability in NO2 concentrations suggests that mobility restriction measures, urbanization intensity, and anthropogenic activity patterns may influence atmospheric pollution dynamics across Central America. The large-scale mobility restrictions implemented worldwide in response to the COVID-19 (SARS-CoV-2) pandemic led to short-term reductions in anthropogenic emissions, providing an opportunity to explore atmospheric pollutant responses to large-scale changes in human activity and mobility patterns. Although numerous studies have reported air quality improvements during lockdowns, most rely on ground-based monitoring networks and focus on developed regions, leaving gaps in less-studied areas such as Central America. This study evaluates spatiotemporal changes in tropospheric nitrogen dioxide (NO2) across Central America before, during, and after COVID-19 lockdowns using satellite-based remote sensing. High-resolution NO2 vertical column density (VCD) data from the TROPOMI instrument onboard Sentinel-5P were processed using Google Earth Engine. Percentage variations were calculated using the March–May 2020 lockdown period as a reference within the 2019–2021 analysis period. Results indicate reductions in NO2 across several high-density departments, particularly in Guatemala, El Salvador, and Honduras, with decreases of 20–30% and localized negative variations below −40%. In contrast, Nicaragua exhibited comparatively limited changes, while a gradual recovery in NO2 concentrations was observed during 2021. The observed patterns suggest a potential association between NO2 variability and changes in anthropogenic activity during the COVID-19 period, while also highlighting the importance of considering meteorological influences in regional atmospheric assessments. The results further demonstrate the potential of cloud-based Earth observation platforms for atmospheric monitoring in data-scarce tropical regions. [ABSTRACT FROM AUTHOR] |
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| Database: | Engineering Source |
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| Abstract: | Highlights: What are the main findings? Satellite-based observations revealed noticeable spatiotemporal variability in tropospheric NO2 concentrations across Central America during the COVID-19 period, with stronger negative variations observed in highly urbanized departments of Guatemala, El Salvador, and Honduras. The integration of Sentinel-5P TROPOMI data within Google Earth Engine enabled a consistent regional-scale assessment of atmospheric variability, highlighting heterogeneous responses among countries with different mobility restriction measures. What are the implications of the main findings? The results demonstrate the potential of cloud-based Earth observation platforms for atmospheric monitoring and air quality assessment in tropical regions characterized by limited ground-based monitoring networks. The observed regional and subnational variability in NO2 concentrations suggests that mobility restriction measures, urbanization intensity, and anthropogenic activity patterns may influence atmospheric pollution dynamics across Central America. The large-scale mobility restrictions implemented worldwide in response to the COVID-19 (SARS-CoV-2) pandemic led to short-term reductions in anthropogenic emissions, providing an opportunity to explore atmospheric pollutant responses to large-scale changes in human activity and mobility patterns. Although numerous studies have reported air quality improvements during lockdowns, most rely on ground-based monitoring networks and focus on developed regions, leaving gaps in less-studied areas such as Central America. This study evaluates spatiotemporal changes in tropospheric nitrogen dioxide (NO2) across Central America before, during, and after COVID-19 lockdowns using satellite-based remote sensing. High-resolution NO2 vertical column density (VCD) data from the TROPOMI instrument onboard Sentinel-5P were processed using Google Earth Engine. Percentage variations were calculated using the March–May 2020 lockdown period as a reference within the 2019–2021 analysis period. Results indicate reductions in NO2 across several high-density departments, particularly in Guatemala, El Salvador, and Honduras, with decreases of 20–30% and localized negative variations below −40%. In contrast, Nicaragua exhibited comparatively limited changes, while a gradual recovery in NO2 concentrations was observed during 2021. The observed patterns suggest a potential association between NO2 variability and changes in anthropogenic activity during the COVID-19 period, while also highlighting the importance of considering meteorological influences in regional atmospheric assessments. The results further demonstrate the potential of cloud-based Earth observation platforms for atmospheric monitoring in data-scarce tropical regions. [ABSTRACT FROM AUTHOR] |
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| ISSN: | 20724292 |
| DOI: | 10.3390/rs18111850 |
