Surface, satellite ozone variations in Northern South America during low anthropogenic emission conditions: a machine learning approach.

Unlabelled: 2020 presented the ideal conditions for studying the air quality response to several emission reductions due to the COVID-19 lockdowns. Numerous studies found that the tropospheric ozone increased even in lockdown conditions, but its reasons are not entirely understood. This research aims to better understand the ozone variations in Northern South America.

Avoidable mortality due to long-term exposure to PM in Colombia 2014-2019.

Objective: To compare estimates of spatiotemporal variations of surface PM concentrations in Colombia from 2014 to 2019 derived from two global air quality models, as well as to quantify the avoidable deaths attributable to the long-term exposure to concentrations above the current and projected Colombian standard for PM annual mean at municipality level.

Methods: We retrieved PM concentrations at the surface level from the ACAG and CAMSRA global air quality models for all 1,122 municipalities, and compare 28 of them with available concentrations from monitor stations. Annual mortality data 2014-2019 by municipality of residence and pooled effect measures for total, natural and specific causes of mortality were used to calculate the number of annual avoidable deaths and years of potential life lost (YPLL) related to the excess of PM concentration over the current mean annual national standard of 25 µg/m and projected standard of 15 µg/m.