Taking as a reference the regional and national context on the subject of air quality and climate change, it has been financed by the United Nations UNU - International Atomic Energy Agency IAEA, Ecopetrol and Área Metropolitana del Valle de Aburrá, a project to mitigate the climate change, with the objective of evaluating the impact of the improvement of diesel delivered by Ecopetrol and strategies of the PIGECA Air Quality Management Plan. A characterization campaign was carried out at a traffic station between 11/23/2018 and 02/16/2019, locating two low-volume meters at Polytechnic traffic monitoring network station under protocols accredited by IDEAM and International Laboratories. The samples were analyzed for elemental, ionic and carbonaceous composition, applying methods (ICP-MS), chromatography and NIOSH 5040 protocol. For the comparison of the changes in the chemical composition of PM2.5, concentration and speciation historical reports for periods of diesel consumption of 25 and 50 ppm of sulfur (S) were analyzed. An analysis of the concentration distribution between march 2008 and february 2019 shows an average decrease of 4.8 (μg / m3) and 5.1 (μg / m3) for 75% of the data. Based on the results of the characterization and previous studies, a greater adjustment of the ionic balance in the composition of the samples in the 2019 campaign was evaluated, showing the effect of the reduction of sulfates of 1.4% in the PM2.5 mass as an impact of the fuel quality improvement and a 2.2% EC reduction associated with the optimization of combustion systems in furnaces and boilers, renewal of the vehicle fleet in public transport and implementation of mobility and sustainable strategies in the metropolitan area. For the first time in the region, a concentration of the potassium ion (K +) is detected, which may be associated with the increase in the consumption of biodiesel in the region. The significant increase in the OC / EC ratio in the period of consumption of lower sulfur diesel (S) and some strong correlations such as that found between SO42– and NH4 +, infer a greater atmospheric reactivity implying the formation of secondary PM2.5 and consequently, a high need to continue with strategies to control primary emissions from all combustion sources.