Photochemical sensitivity to emissions and local meteorology in Bogotá, Santiago, and São Paulo
Journal
Elementa: Science of the Anthropocene
ISSN
2325-1026
Date Issued
2022
Author(s)
Rodrigo J. Seguel
Laura Gallardo
Mauricio Osses
Néstor Y. Rojas
Thiago Nogueira
Camilo Menares
Maria de Fatima Andrade
Luis C. Belalcázar
Paula Carrasco
Henk Eskes
Nicolas Huneeus
Sergio Ibarra-Espinosa
Eduardo Landulfo
Manuel Leiva
Sonia C. Mangones
Fernando G. Morais
Gregori A. Moreira
Nicolás Pantoja
Santiago Parraguez
Jhojan P. Rojas
Roberto Rondanelli
Izabel da Silva Andrade
Richard Toro
Alexandre C. Yoshida
Type
Resource Types::text::journal::journal article
URL Institutional Repository
Abstract
<jats:p>This study delves into the photochemical atmospheric changes reported globally during the pandemic by analyzing the change in emissions from mobile sources and the contribution of local meteorology to ozone (O3) and particle formation in Bogotá (Colombia), Santiago (Chile), and São Paulo (Brazil). The impact of mobility reductions (50%–80%) produced by the early coronavirus-imposed lockdown was assessed through high-resolution vehicular emission inventories, surface measurements, aerosol optical depth and size, and satellite observations of tropospheric nitrogen dioxide (NO2) columns. A generalized additive model (GAM) technique was also used to separate the local meteorology and urban patterns from other drivers relevant for O3 and NO2 formation. Volatile organic compounds, nitrogen oxides (NOx), and fine particulate matter (PM2.5) decreased significantly due to motorized trip reductions. In situ nitrogen oxide median surface mixing ratios declined by 70%, 67%, and 67% in Bogotá, Santiago, and São Paulo, respectively. NO2 column medians from satellite observations decreased by 40%, 35%, and 47%, respectively, which was consistent with the changes in mobility and surface mixing ratio reductions of 34%, 25%, and 34%. However, the ambient NO2 to NOx ratio increased, denoting a shift of the O3 formation regime that led to a 51%, 36%, and 30% increase in the median O3 surface mixing ratios in the 3 respective cities. O3 showed high sensitivity to slight temperature changes during the pandemic lockdown period analyzed. However, the GAM results indicate that O3 increases were mainly caused by emission changes. The lockdown led to an increase in the median of the maximum daily 8-h average O3 of between 56% and 90% in these cities.</jats:p>
Dataset(s)
Subjects
vehicular emissions
;
air-quality
;
ozone
;
evolution
;
aerosols
;
city
;
bogota
;
brazil
;
colombia
;
rio grande do sul
;
santiago [rio grande do sul]
;
sao paulo [brazil]
;
covid-19
;
emission control
;
emission inventory
;
meteorology
;
nitrogen oxides
;
numerical model
;
ozone
;
photochemistry
;
pollutant source
;
satellite altimetry
;
sensitivity analysis