{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,28]],"date-time":"2026-01-28T04:27:36Z","timestamp":1769574456433,"version":"3.49.0"},"reference-count":59,"publisher":"MDPI AG","issue":"18","license":[{"start":{"date-parts":[[2024,9,16]],"date-time":"2024-09-16T00:00:00Z","timestamp":1726444800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>This study uses a remote sensing approach to investigate air quality fluctuations during two short-period social upheaval events caused by civil protests in 2019 and the COVID-19 pandemic in 2020 in Quito, Ecuador. We used data from the TROPOMI Sentinel-P5 satellite to evaluate the concentrations of two greenhouse gases, namely O3 and NO2. TROPOMI Sentinel-P5 satellite data are becoming essential in air quality monitoring, particularly for countries that lack ground-based monitoring systems. For a better approximation of satellite data with ground data, we related the remotely sensed data using ground station data and Pearson correlation analysis, which revealed a significant association between the two sources (0.43 \u2264 r \u2264 0.78). Using paired t-test comparisons, we evaluated the differences in mean gas concentrations at 30 randomly selected intervals to identify significant changes before and after the events. The results indicate noticeable changes in the two gases over the three analysis periods. O3 significantly decreased between September and November 2019 and between March and May 2020, while NO2 significantly increased. NO2 levels decreased by 18% between February and March 2020 across the study area, as indicated by remote sensing data. The geovisualization of remotely sensed data over these periods supports these patterns, suggesting a potential connection with population density. The results show the complexity of drawing global conclusions about the impact of social disruptions on the atmosphere and emphasize the advantages of using remote sensing as an effective framework to address air quality changes over short periods of time. This study also highlights the advantages of a remote sensing approach to monitor atmospheric conditions in countries with limited air quality monitoring infrastructure and provides a valuable approach for the evaluation of short-term alterations in atmospheric conditions due to social disturbance events.<\/jats:p>","DOI":"10.3390\/rs16183436","type":"journal-article","created":{"date-parts":[[2024,9,16]],"date-time":"2024-09-16T10:56:57Z","timestamp":1726484217000},"page":"3436","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":9,"title":["Assessing Air Quality Dynamics during Short-Period Social Upheaval Events in Quito, Ecuador, Using a Remote Sensing Framework"],"prefix":"10.3390","volume":"16","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-5629-0893","authenticated-orcid":false,"given":"Cesar Ivan","family":"Alvarez","sequence":"first","affiliation":[{"name":"Department of Environmental and Civil Engineering, Environmental Research Group on Sustainable Development (GIADES), Salesian Polytechnic University, Quito 170702, Ecuador"}]},{"given":"Santiago","family":"L\u00f3pez","sequence":"additional","affiliation":[{"name":"School of Interdisciplinary Arts and Sciences, University of Washington Bothell, Bothell, WA 98011, USA"}]},{"given":"David","family":"V\u00e1squez","sequence":"additional","affiliation":[{"name":"Department of Environmental and Civil Engineering, Environmental Research Group on Sustainable Development (GIADES), Salesian Polytechnic University, Quito 170702, Ecuador"}]},{"ORCID":"https:\/\/orcid.org\/0009-0002-6679-2082","authenticated-orcid":false,"given":"Dayana","family":"Gualotu\u00f1a","sequence":"additional","affiliation":[{"name":"Department of Environmental and Civil Engineering, Environmental Research Group on Sustainable Development (GIADES), Salesian Polytechnic University, Quito 170702, Ecuador"}]}],"member":"1968","published-online":{"date-parts":[[2024,9,16]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"470","DOI":"10.1038\/s43017-020-0079-1","article-title":"The COVID-19 Lockdowns: A Window into the Earth System","volume":"1","author":"Diffenbaugh","year":"2020","journal-title":"Nat. Rev. Earth Environ."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"501","DOI":"10.1080\/00207230600802148","article-title":"The Impact of 9\/11 on the Association of Ambient Air Pollutions with Daily Respiratory Hospital Admissions in a Canada-US Border City, Windsor, Ontario","volume":"63","author":"Luginaah","year":"2006","journal-title":"Int. J. Environ. Stud."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"76","DOI":"10.1016\/j.tranpol.2020.07.001","article-title":"Insights into the Impact of COVID-19 on Household Travel and Activities in Australia\u2014The Early Days under Restrictions","volume":"96","author":"Beck","year":"2020","journal-title":"Transp. Policy"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"184","DOI":"10.1016\/j.ijtst.2020.11.003","article-title":"COVID-19 Pandemic Impacts on Traffic System Delay, Fuel Consumption and Emissions","volume":"10","author":"Du","year":"2021","journal-title":"Int. J. Transp. Sci. Technol."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"10953","DOI":"10.1002\/er.5706","article-title":"Impact of Coronavirus (COVID-19) Pandemic on Air Transport Mobility, Energy, and Environment: A Case Study","volume":"44","year":"2020","journal-title":"Int. J. Energy Res."},{"key":"ref_6","unstructured":"Kinver, M. (2023, October 29). Then and Now: Pandemic Clears the Air. Available online: https:\/\/www.bbc.com\/news\/science-environment-57149747."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"348","DOI":"10.1177\/001979398904200302","article-title":"One Hundred Years of Strike Statistics: Methodological and Theoretical Issues in Quantitative Strike Research","volume":"42","author":"Franzosi","year":"1989","journal-title":"ILR Rev."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"7915","DOI":"10.1016\/j.atmosenv.2008.07.046","article-title":"Influence of the Public Transportation System on the Air Quality of a Major Urban Center. A Case Study: Milan, Italy","volume":"42","author":"Meinardi","year":"2008","journal-title":"Atmos. Environ."},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Zalakeviciute, R., Alexandrino, K., Mejia, D., Bastidas, M.G., Oleas, N.H., Gabela, D., Chau, P.N., Bonilla-Bedoya, S., Diaz, V., and Rybarczyk, Y. (2021). The Effect of National Protest in Ecuador on PM Pollution. Sci. Rep., 11.","DOI":"10.1038\/s41598-021-96868-6"},{"key":"ref_10","first-page":"98","article-title":"Contrasting Effects of Air Pollution Asessment in Two Areas of the Quito Metropolitan District, Ecuador","volume":"36","author":"Cornejo","year":"2022","journal-title":"La Granja"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"150797","DOI":"10.1016\/j.scitotenv.2021.150797","article-title":"Long-Term Evaluation of a Low-Cost Air Sensor Network for Monitoring Indoor and Outdoor Air Quality at the Community Scale","volume":"807","author":"Connolly","year":"2022","journal-title":"Sci. Total Environ."},{"key":"ref_12","first-page":"159","article-title":"Evaluaci\u00f3n de La Calidad Del Aire Durante El Tiempo de Protestas En Ciudades Sudamericanas","volume":"2023","year":"2023","journal-title":"Rev. Geogr. Norte Gd."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1257\/pol.20150414","article-title":"When Labor Disputes Bring Cities to a Standstill: The Impact of Public Transit Strikes on Traffic, Accidents, Air Pollution, and Health","volume":"9","author":"Bauernschuster","year":"2017","journal-title":"Am. Econ. J. Econ. Policy"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"10133","DOI":"10.5194\/acp-16-10133-2016","article-title":"Nine Years of Global Hydrocarbon Emissions Based on Source Inversion of OMI Formaldehyde Observations","volume":"16","author":"Bauwens","year":"2016","journal-title":"Atmos. Chem. Phys."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"140353","DOI":"10.1016\/j.scitotenv.2020.140353","article-title":"COVID-19 Lockdown Effects on Air Quality by NO2 in the Cities of Barcelona and Madrid (Spain)","volume":"741","author":"Baldasano","year":"2020","journal-title":"Sci. Total Environ."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"141023","DOI":"10.1016\/j.scitotenv.2020.141023","article-title":"Non-Negligible Impacts of Clean Air Regulations on the Reduction of Tropospheric NO2 over East China during the COVID-19 Pandemic Observed by OMI and TROPOMI","volume":"745","author":"Huang","year":"2020","journal-title":"Sci. Total Environ."},{"key":"ref_17","unstructured":"The National Academy of Sciences (2020). Climate Change Evidence and Causes: Update 2020, The National Academy of Sciences."},{"key":"ref_18","unstructured":"(2023, October 29). EPA Basic Information about NO2|US EPA, Available online: https:\/\/www.epa.gov\/no2-pollution\/basic-information-about-no2."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"11887","DOI":"10.5194\/acp-19-11887-2019","article-title":"Exploring the Impacts of Anthropogenic Emission Sectors on PM2.5 and Human Health in South and East Asia","volume":"19","author":"Reddington","year":"2019","journal-title":"Atmos. Chem. Phys."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"331","DOI":"10.1515\/reveh-2022-0237","article-title":"Effects of Sulfur Dioxide Inhalation on Human Health: A Review","volume":"39","author":"Khalaf","year":"2022","journal-title":"Rev. Environ. Health"},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Zhang, Z., and Zhu, L. (2023). A Review on Unmanned Aerial Vehicle Remote Sensing: Platforms, Sensors, Data Processing Methods, and Applications. Drones, 7.","DOI":"10.3390\/drones7060398"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"1134","DOI":"10.1164\/rccm.201508-1633OC","article-title":"Long-Term Ozone Exposure and Mortality in a Large Prospective Study","volume":"193","author":"Turner","year":"2016","journal-title":"Am. J. Respir. Crit. Care Med."},{"key":"ref_23","first-page":"45","article-title":"Assessment of Fuel Related Data in the Metropolitan District of Quito for Modeling and Simulation of Wildfires, Case Study: Atacazo Hill Wildfire","volume":"34","author":"Mollocana","year":"2021","journal-title":"La Granja"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"262","DOI":"10.1002\/met.288","article-title":"Satellite Based Remote Sensing of Weather and Climate: Recent Achievements and Future Perspectives","volume":"18","author":"Thies","year":"2011","journal-title":"Meteorol. Appl."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"116","DOI":"10.1016\/j.aca.2014.10.018","article-title":"Current Air Quality Analytics and Monitoring: A Review","volume":"853","author":"Tobiszewski","year":"2015","journal-title":"Anal. Chim. Acta"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"13","DOI":"10.1186\/s43591-021-00014-y","article-title":"Hyperspectral Imaging as an Emerging Tool to Analyze Microplastics: A Systematic Review and Recommendations for Future Development","volume":"1","author":"Faltynkova","year":"2021","journal-title":"Microplastics Nanoplastics"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"102273","DOI":"10.1016\/j.apgeog.2020.102273","article-title":"Spatial Estimation of Chronic Respiratory Diseases Based on Machine Learning Procedures\u2014An Approach Using Remote Sensing Data and Environmental Variables in Quito, Ecuador","volume":"123","author":"Teodoro","year":"2020","journal-title":"Appl. Geogr."},{"key":"ref_28","doi-asserted-by":"crossref","unstructured":"\u00c1lvarez, C. (2023). The Use of Remote Sensing in Air Pollution Control and Public Health. Socio-Environmental Research in Latin America. The Latin American Studies Book Series, Springer.","DOI":"10.1007\/978-3-031-22680-9_7"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"1222","DOI":"10.4209\/aaqr.2020.04.0171","article-title":"Social and Travel Lockdown Impact Considering Coronavirus Disease (COVID-19) on Air Quality in Megacities of India: Present Benefits, Future Challenges and Way Forward","volume":"20","author":"Jain","year":"2020","journal-title":"Aerosol Air Qual. Res."},{"key":"ref_30","unstructured":"Forster, T., and Santini, G. (2023, October 29). Reinforcing Rural-Urban Linkages Resilient Food Systems. Available online: https:\/\/openknowledge.fao.org\/server\/api\/core\/bitstreams\/9ff9bb27-ec9a-49c4-9f7e-81253ee28c9f\/content."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"104521","DOI":"10.1016\/j.jpubeco.2021.104521","article-title":"Environmental Regulations and International Trade: A Quantitative Economic Analysis of World Pollution Emissions","volume":"203","author":"Duan","year":"2021","journal-title":"J. Public Econ."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"78","DOI":"10.1111\/1758-5899.12944","article-title":"Inequality and the Socioeconomic Dimensions of Mobility in Protests: The Cases of Quito and Santiago","volume":"12","author":"Palacio","year":"2021","journal-title":"Glob. Policy"},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"1783","DOI":"10.4209\/aaqr.2020.05.0254","article-title":"Drastic Improvements in Air Quality in Ecuador during the COVID-19 Outbreak","volume":"20","author":"Zalakeviciute","year":"2020","journal-title":"Aerosol Air Qual. Res."},{"key":"ref_34","first-page":"1","article-title":"A Critical Narrative of Ecuador\u2019s Preparedness and Response to the COVID-19 Pandemic","volume":"2","author":"Alava","year":"2021","journal-title":"Public Health Pract."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"645","DOI":"10.3155\/1047-3289.59.6.645","article-title":"Remote Sensing of Pariculate Pollution from Space: Have We Reached the Promised Land?","volume":"129","author":"Hoff","year":"2009","journal-title":"J. Air. Waste Manag. Assoc."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"264","DOI":"10.4236\/jep.2010.13032","article-title":"Spatial and Temporal Variation of Urban Air Quality: A GIS Approach","volume":"01","author":"Chattopadhyay","year":"2010","journal-title":"J. Environ. Prot. (Irvine Calif.)"},{"key":"ref_37","first-page":"e8273","article-title":"Effect of Using an Indoor Air Quality Sensor on Perceptions of and Behaviors toward Air Pollution (Pittsburgh Empowerment Library Study): Online Survey and Interviews","volume":"6","author":"Dias","year":"2018","journal-title":"JMIR mHealth uHealth"},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"929","DOI":"10.1007\/s11869-020-00866-y","article-title":"Has Air Quality Improved in Ecuador during the COVID-19 Pandemic? A Parametric Analysis","volume":"13","author":"Zambrano","year":"2020","journal-title":"Air Qual. Atmos. Health"},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"5563","DOI":"10.5194\/amt-15-5563-2022","article-title":"Tropospheric Ozone Retrieval by a Combination of TROPOMI\/S5P Measurements with BASCOE Assimilated Data","volume":"15","author":"Heue","year":"2022","journal-title":"Atmos. Meas. Tech."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"18","DOI":"10.1016\/j.rse.2017.06.031","article-title":"Google Earth Engine: Planetary-Scale Geospatial Analysis for Everyone","volume":"202","author":"Gorelick","year":"2017","journal-title":"Remote Sens. Environ."},{"key":"ref_41","doi-asserted-by":"crossref","unstructured":"Grzybowski, P.T., Markowicz, K.M., and Musia\u0142, J.P. (2023). Estimations of the Ground-Level NO2 Concentrations Based on the Sentinel-5P NO2 Tropospheric Column Number Density Product. Remote Sens., 15.","DOI":"10.3390\/rs15020378"},{"key":"ref_42","unstructured":"UNDP (2020). COVID-19 Impact on Air Quality in Ukraine and the Republic of Moldova Work Order, UNDP."},{"key":"ref_43","doi-asserted-by":"crossref","unstructured":"Kelly, J., Zhao, J., Xing, J., Zhang, Y., Han, S., Kundhikanjana, W., Towashiraporn, P., and Stratoulias, D. (2022). Interpolation-Based Fusion of Sentinel-5P, SRTM, and Regulatory-Grade Ground Stations Data for Producing Spatially Continuous Maps of PM2.5 Concentrations Nationwide over Thailand. Atmosphere, 13.","DOI":"10.3390\/atmos13020161"},{"key":"ref_44","first-page":"101083","article-title":"TROPOMI NO2 Sentinel-5P Data in the Community of Madrid: A Detailed Consistency Analysis with in Situ Surface Observations","volume":"33","author":"Morillas","year":"2024","journal-title":"Remote Sens. Appl. Soc. Environ."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"411","DOI":"10.1007\/s11869-020-00946-z","article-title":"Application of Satellite Data and GIS Services for Studying Air Pollutants in Lithuania (Case Study: Kaunas City)","volume":"14","author":"Soleimany","year":"2021","journal-title":"Air Qual. Atmos. Health"},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"128","DOI":"10.4209\/aaqr.2010.07.0055","article-title":"Analysis of the Relationship between O3, NO and NO2 in Tianjin, China","volume":"11","author":"Han","year":"2011","journal-title":"Aerosol Air Qual. Res."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"140005","DOI":"10.1016\/j.scitotenv.2020.140005","article-title":"Assessing the Relationship between Ground Levels of Ozone (O3) and Nitrogen Dioxide (NO2) with Coronavirus (COVID-19) in Milan, Italy","volume":"740","author":"Zoran","year":"2020","journal-title":"Sci. Total Environ."},{"key":"ref_48","unstructured":"World Health Organization (WHO) (2021). WHO Global Air Quality Guidelines, WHO."},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"109645","DOI":"10.1016\/j.jenvman.2019.109645","article-title":"Surface Ozone Climatology of South Eastern Brazil and the Impact of Biomass Burning Events","volume":"252","author":"Targino","year":"2019","journal-title":"J. Environ. Manag."},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"541","DOI":"10.1007\/s11869-022-01168-1","article-title":"Air Quality and Photochemical Reactions: Analysis of NOx and NO2 Concentrations in the Urban Area of Turin, Italy","volume":"15","author":"Ravina","year":"2022","journal-title":"Air Qual. Atmos. Health"},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"e17033","DOI":"10.1016\/j.heliyon.2023.e17033","article-title":"Assessment of Variations in Air Quality in Cities of Ecuador in Relation to the Lockdown Due to the COVID-19 Pandemic","volume":"9","author":"Atiaga","year":"2023","journal-title":"Heliyon"},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"139864","DOI":"10.1016\/j.scitotenv.2020.139864","article-title":"Changes in U.S. Air Pollution during the COVID-19 Pandemic","volume":"739","author":"Berman","year":"2020","journal-title":"Sci. Total Environ."},{"key":"ref_53","first-page":"80","article-title":"Monitoring Air Quality Using Remote Sensing Based on a Google Earth Engine Application in Countries with Limited Air Quality Data and Control Policies: A Case Study in Ecuador","volume":"12735","author":"Lopez","year":"2023","journal-title":"Remote Sens. Technol. Appl. Urban Environ. VIII"},{"key":"ref_54","doi-asserted-by":"crossref","first-page":"162163","DOI":"10.1016\/j.scitotenv.2023.162163","article-title":"Critical Review on Emerging Health Effects Associated with the Indoor Air Quality and Its Sustainable Management","volume":"872","author":"Kumar","year":"2023","journal-title":"Sci. Total Environ."},{"key":"ref_55","doi-asserted-by":"crossref","first-page":"166340","DOI":"10.1016\/j.scitotenv.2023.166340","article-title":"The Impact of Air Pollution on Respiratory Diseases in an Era of Climate Change: A Review of the Current Evidence","volume":"898","author":"Tran","year":"2023","journal-title":"Sci. Total Environ."},{"key":"ref_56","doi-asserted-by":"crossref","unstructured":"Alvarez, C., Teodoro, A., Torres, N., and Vivanco, V. (2019). Assessment of Remote Sensing Data to Model PM10 Estimation in Cities with a Low Number of Air Quality Stations: A Case of Study in Quito, Ecuador. Environments, 6.","DOI":"10.3390\/environments6070085"},{"key":"ref_57","doi-asserted-by":"crossref","first-page":"100622","DOI":"10.1016\/j.wace.2023.100622","article-title":"Attribution of Extreme Events to Climate Change in the Australian Region\u2014A Review","volume":"42","author":"Lane","year":"2023","journal-title":"Weather Clim. Extrem."},{"key":"ref_58","doi-asserted-by":"crossref","first-page":"100936","DOI":"10.1016\/j.lanwpc.2023.100936","article-title":"Climate Change, Environmental Extremes, and Human Health in Australia: Challenges, Adaptation Strategies, and Policy Gaps","volume":"40","author":"Xu","year":"2023","journal-title":"Lancet Reg. Health-West. Pacific"},{"key":"ref_59","doi-asserted-by":"crossref","first-page":"4001","DOI":"10.1002\/jgrd.50239","article-title":"Attribution of Observed Historical Near-Surface Temperature Variations to Anthropogenic and Natural Causes Using CMIP5 Simulations","volume":"118","author":"Jones","year":"2013","journal-title":"J. Geophys. Res. Atmos."}],"container-title":["Remote Sensing"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-4292\/16\/18\/3436\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T15:57:28Z","timestamp":1760111848000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-4292\/16\/18\/3436"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2024,9,16]]},"references-count":59,"journal-issue":{"issue":"18","published-online":{"date-parts":[[2024,9]]}},"alternative-id":["rs16183436"],"URL":"https:\/\/doi.org\/10.3390\/rs16183436","relation":{},"ISSN":["2072-4292"],"issn-type":[{"value":"2072-4292","type":"electronic"}],"subject":[],"published":{"date-parts":[[2024,9,16]]}}}