Assessment of variations in air quality in cities of Ecuador in relation to the lockdown due to the COVID-19 pandemic
Oliva Atiaga,
Fernanda Guerrero,
Fernando Páez,
Rafael Castro,
Edison Collahuazo,
Luís Miguel Nunes,
Marcelo Grijalva,
Iván Grijalva,
Xosé Luis Otero
Affiliations
Oliva Atiaga
Departamento de Ciencias de la Tierra y la Construcción, Universidad de las Fuerzas Armadas ESPE, Av. General Rumiñahui s/n, Sangolquí, P.O. Box 171-5-231B, Ecuador; CRETUS. Departamento de Edafoloxía e Química Agrícola, Facultade de Bioloxía, Universidade de Santiago de Compostela, Campus Sur, 15782 Santiago de Compostela, Spain
Fernanda Guerrero
Departamento de Ciencias de la Tierra y la Construcción, Universidad de las Fuerzas Armadas ESPE, Av. General Rumiñahui s/n, Sangolquí, P.O. Box 171-5-231B, Ecuador
Fernando Páez
Departamento de Ciencias de la Tierra y la Construcción, Universidad de las Fuerzas Armadas ESPE, Av. General Rumiñahui s/n, Sangolquí, P.O. Box 171-5-231B, Ecuador
Rafael Castro
Geospace Solutions, Av. Manuel Córdova Galarza km 4.5, P.O. Box 170177, Ecuador
Edison Collahuazo
Geospace Solutions, Av. Manuel Córdova Galarza km 4.5, P.O. Box 170177, Ecuador
Luís Miguel Nunes
Faculdade de Ciências e Tecnologia, Universidade do Algarve, Campus de Gambelas, Faro, Portugal; CERIS, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais 1, 1049-001, Lisboa, Portugal; Corresponding author. Faculdade de Ciências e Tecnologia, Universidade do Algarve, Campus de Gambelas, Faro, Portugal.
Marcelo Grijalva
Departamento de Ciencias de la Vida, Universidad de las Fuerzas Armadas ESPE, Av. General Rumiñahui s/n, Sangolquí, P.O. Box 171-5-231B, Ecuador
Iván Grijalva
Independent consultant. Avenida Amazonas N22-62 y Ramirez Dávalos, PO BOX 170526, Quito, Ecuador
Xosé Luis Otero
CRETUS. Departamento de Edafoloxía e Química Agrícola, Facultade de Bioloxía, Universidade de Santiago de Compostela, Campus Sur, 15782 Santiago de Compostela, Spain; REBUSC Network of Biological Field Stations of the University of Santiago de Compostela, Marine Biology Stations of A Graña and Ferrol, University of Santiago de Compostela, 15782 Santiago de Compostela, Spain
This study analyzes the effect of lockdown due to COVID-19 on the spatiotemporal variability of ozone (O3), sulfur dioxide (SO2), and nitrogen dioxide (NO2) concentrations in different provinces of continental Ecuador using satellite information from Sentinel – 5P. The statistical analysis includes data from 2018 to March 2021 and was performed based on three periods defined a priori: before, during, and after lockdown due to COVID-19, focusing on the provinces with the highest concentrations of the studied gases (hotspots). The results showed a significant decrease in NO2 concentrations during the COVID-19 lockdown period in all the study areas: the Metropolitan District of Quito (DMQ) and the provinces of Guayas and Santo Domingo de los Tsáchilas. In the period after lockdown, NO2 concentrations increased by over 20% when compared to the pre-lockdown period, which may be attributable to a shift towards private transportation due to health concerns. On the other hand, SO2 concentrations during the lockdown period showed irregular, non-significant variations; however, increases were observed in the provinces of Chimborazo, Guayas, Santa Elena, and Morona Santiago, which could be partly attributed to the eruptive activity of the Sangay volcano during 2019–2020. Conversely, O3 concentrations increased by 2–3% in the study areas; this anomalous behavior could be attributed to decreased levels of NOx, which react with ozone, reducing its concentration. Finally, satellite data validation using the corresponding data from monitoring stations in the DMQ showed correlation values of 0.9 for O3 data and 0.7 for NO2 data, while no significant correlation was found for SO2.
