The Negative Impact of Biomass Burning and the Orinoco Low-Level Jet on the Air Quality of the Orinoco River Basin

Biomass burning (BB) is a common activity in developing countries and has been identified as a serious air pollution threat. The present work evaluates the air quality of the largest town in the extensive Colombian savannas (250,000 km2) for the first time, from measurements over three consecutive years (2017-2020). Although the air quality in Villavicencio is good in terms of PM10 and O3 for most of the year, the pollution levels for both pollutants exceed the World Health Organization recommended limits during the dry season (February to April). The combination of the Orinoco low-level jet (OLLJ) with the BB emissions from the Venezuelan and the Colombian savannas was identified as the main cause of the poor air quality episodes during the dry season in this city. Organic carbon derived from reanalysis was identified as the main component of the high PM10 concentrations during the dry season. However, mineral dust and sea salt particles were also found to play an important role in the poor air quality observed in Villavicencio and likely along the Orinoco river basin region. Finally, between November and March, the OLLJ was found to be an efficient mechanism for the transport of air pollutants from the Atlantic Ocean and the savannas regions in the Orinoco River Basin in Venezuela and Colombia towards southern regions of Colombia, and in some cases, Ecuador.