This document examines the relationship between pollution levels and mental health in children in Colombia. For the analysis, the mental health variable is taken as the results of the SDQ-Cas questionnaire obtained from the children's module of the 2016 ELCA (Longitudinal Study in Colombia) in a georeferenced manner for the cities of Bogotá and Medellín, cities with a strong industrial tradition. The expectation is to find a correlation between the SDQ-Cas test outcomes and pollution levels for both cities. For the pollution variable, daily measurements of nitrogen dioxide and particulate matter PM10 y PM2.5 concentrations are taken for each city; however, since the pollution variable is endogenous, an instrument is constructed using thermal inversions. The results show that thermal inversions are a strong instrument in the first stage and indicate minor impacts of pollution levels on mental health in the second stage, but this result does not hold up under robustness checks. In conclusion, there are indications of some effects of pollution on mental health; however, the existence of this relationship in children in Colombia cannot be conclusively established.
