Most of the time, CO and eBC are correlated in Chacaltaya, pointing at a vehicular origin of those emissions, but in several cases both pollutants are decoupled. 50 cases of the latter were studied together with meteorological variables, back trajectories, satellite images and hot spots derived from satellite data in order to find the reason of the decoupling.
Interestingly, the decoupling could be explained when different conditions were present: biomass burning, residual layer pollution (both regional and from the city nearby), high relative humidity, the transition between free troposphere and mixing layer and the change on wind speed and direction. The relationship between those factors and the studied pollutants was not direct, but they could explain half of the studied cases.
As in some cases it was not possible to find a reason for the decoupling, more studies are needed.