Particulate matter (PM) is a complex mixture of particles that changes over time and from place to place; however, most PM is caused by the fuel combustion of motor vehicles and industry. PM is associated with acute and chronic illnesses, such as pulmonary and cardiovascular diseases. Medellín is one of the most polluted cities in Latin America. Therefore, the physicochemical characterization of its PM is necessary to understand its composition and effect on human health. In this study, PM was characterized by scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDS) analysis, Fourier infrared spectroscopy (FTIR), inductivity-coupled plasma optical emission spectrometry (ICP-OES), and thermogravimetric analysis (TGA) in order to evaluate its morphology and chemical composition. The SEM of the PM exhibited primary particles and agglomerates. The size of the particles ranged between 0.056 and 4.5 μm. The EDS revealed elements such as carbon, silicon, calcium, lead, and iron. Furthermore, carbon monoxide, carbon dioxide, and carbonyl and aliphatic functional groups were observed by means of FTIR. Additionally, weight losses associated with volatile matter and elemental carbon were identified in the TGA analysis. The TGA and FTIR confirmed the presence of fuel and lubricant traces. Subsequently, lead was selected among the most common components in the PM in order to conduct an in silico study into its effect on ventricular activity. Lead showed a pro-arrhythmic effect by shortening the duration of the action potential under normal electrophysiological conditions, which could be associated with cardiovascular diseases. © 2020, Springer Nature Switzerland AG.