Impact of lockdown on particulate matter concentrations in Colombia during the COVID-19 pandemic

https://doi.org/10.1016/j.scitotenv.2020.142874Get rights and content

Highlights

  • The COVID-19 pandemic triggered closures in Colombia that greatly reduced PM2.5 concentrations.

  • The capital of Colombia (Bogotá) and regions in the north of the country experienced a decline (68% and 86%) in PM2.5.

  • The PM2.5 reductions are associated with reduced vehicular traffic due to lockdown.

  • The spatial and temporal values of AOD are related to regional rainfall and Saharan dust over coastal areas.

Abstract

The first confirmed case of COVID-19 in Colombia was reported on March 6, 2020. For this reason, on March 25, preventive isolation was declared mandatory. These measures involved the suspension of economic activities and drastically reduced the number of vehicles on the road. The objective of this study is to evaluate the impact of the lockdown due to the COVID-19 pandemic on PM2.5 concentrations at 5 monitoring stations and aerosol optical depth values of the Terra/MODIS satellite. We analyzed and compared the weekly and monthly concentrations of PM2.5 before and during the lockdown between the week of January 6 to June 22, 2020, and compared the daily values obtained from the Terra/MODIS satellite for the months of January–June during the years 2018–2020 to elucidate the effects of the lockdown. Similar to other monitored sites in the world, we observed substantial reductions in weekly PM2.5 concentrations, from 41 to 84% (Bogotá), from 13 to 66% (Funza), from 17 to 57% (Boyacá), from 35 to 86% (Valledupar) and 31 at 60% (Risaralda). Unlike other studies, the aerosol optical depth values increased up to 59% during the months of lockdown compared to previous years and up to 70% of the weekly mean when compared to before the lockdown. These spatiotemporal behaviors of PM2.5 and the aerosol optical depth in Colombia are influenced by reductions in vehicular flow during quarantine, regional rainfall, and height of the planetary boundary layer. Emissions from economic activities affect pollutant levels in the area. The analysis of the levels of pollutants during the lockdown provides a baseline for regulatory agencies to establish mitigation plans.

Keywords

COVID-19
PM2.5
AOD

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