The East Mediterranean region faces elevated concentrations of PM resulting from transported pollution mixed with anthropogenic emissions (traffic, industrial, and residential emissions), and natural emissions (Saharan and African deserts) . It is considered as a hotspot of climate change where model projections show elevated temperatures by the end of the century leading to the increase of photochemical air pollution . Therefore, it is crucial to determine the sources of pollution and the species that contribute the most to the toxicity in order to develop efficient air quality strategies. PM2.5 samples were collected between December 2018 and October 2019 in an urban site under industrial influence in Lebanon: Zouk Mikael region (ZK). ZK is characterized by the biggest power plant in the country which runs on heavy fuel oil, a high density of population along with high number of diesel private generators and traffic. PM2.5 samples were characterized for their carbonaceous fraction, water-soluble ions, elements, and organic species. Several species and tracer compounds were gathered in the USEPA-PMF model in order to assess the contribution of the sources to the PM2.5 concentrations. Crustal dust and secondary ammonium sulfate sources contributed to 43% of PM2.5. Vehicular and industrial emissions were two important sources at ZK contributing to 14% and 13% of PM2.5, respectively. Furthermore, primary and secondary biogenic emissions contributed to 9% of PM2.5. On the other hand, the oxidation properties of PM components were studied using the oxidative potential (OP) with two acellular methods: the ascorbic acid (AA) and the dithiothreitol (DTT) assays. The mean volume normalized OP-AAv value was 0.67 ± 0.29 nmol.min¬-1.m-3 and the mean OP-DTTv was 0.52 ± 0.32 nmol.min-1.m-3. A multiple linear regression approach was applied to the contribution of the sources obtained by PMF and the OP in order to estimate the contributions of PM sources to OP values. The results showed that local anthropogenic sources such as biomass burning (33% of OP-AAv and 9% of OP-DTTv), vehicular emissions (20% and 23%), and heavy fuel oil combustion (31% and 46%) contribute the most to the OP-AAv and OP-DTTv, respectively.