Association between long-term air pollution exposure and COVID-19 mortality in Latin America

Abstract

Recent studies have shown a relationship between air pollution and increased vulnerability and mortality due to COVID-19. Most of these studies have looked at developed countries. This study examines the relationship between long-term exposure to air pollution and COVID-19-related deaths in four countries of Latin America that have been highly affected by the pandemic: Brazil, Chile, Colombia, and Mexico. Our results suggest that an increase in long-term exposure of 1 μg/m3 of fine particles is associated with a 2.7 percent increase in the COVID-19 mortality rate. This relationship is found primarily in municipalities of metropolitan areas, where urban air pollution sources dominate, and air quality guidelines are usually exceeded. By focusing the analysis on Latin America, we provide a first glimpse on the role of air pollution as a risk factor for COVID-19 mortality within a context characterized by weak environmental institutions, limited health care capacity and high levels of inequality.

Fig 1. Distribution of long-term pollution (PM_2.5) concentrations and COVID-19 deaths in Latin America.

a: Brazil; b: Chile; c: Colombia; d: Mexico. Notes: This figure shows the spatial distribution of long-term fine particulate matter (PM2.5) concentrations, averaged from 2000 to 2018, and 2020 COVID-19 mortality rate per 1,000 people across municipalities of selected countries in Latin America. We measure pollution in μg/m3, and the data correspond to long-term trends of PM2.5 concentrations obtained from [45]. Data on municipality-level COVID-19 mortality rates come from each country’s official sources for 2020. Maps for this study were created in ArcMap 10.3. The basemaps were adapted from Esri, DeLorme, HERE [47] and have been republished under a CC BY license, with permission, original copyright (2021). The shapefiles for Brazil and Chile were adapted from [48, 49], respectively. The shapefiles for Colombia were adapted from IGAC [50] and have been republished under a CC BY license, with permission, original copyright (2022). The shapefiles for Mexico were adapted from INEGI [51] and have been republished under a CC BY license, with permission, original copyright (2010).

Fig 2. COVID-19 mortality rate and long-term PM_2.5 concentrations in Latin American municipalities.

Notes: This figure shows the relationship between COVID-19 mortality rate and long-term average PM2.5 concentrations across Latin American municipalities within metropolitan and non-metropolitan areas. The dashed blue line represents a linear prediction with confidence intervals obtained at the 95% significance (shaded areas). The mortality rate is per 1,000 people. Pollution is measured in μg/m3. Data on mortality rates come from the sources mentioned in the data section. Data on pollution concentrations are long-term trends of fine particulate matter concentrations obtained from [45].