The sources of airborne fine particles in PM2.5 range influencing air quality at Ashaiman, a semi-urban town north of Tema in Ghana had been investigated. Nuclepore and quartz fiber filters were used for the air particulate loadings and analyzed for elemental and carbonaceous compound (EC and OC) concentrations in the 8 carbon fractions using X-Ray spectrometry system and IMPROVE/Thermal Optical Reflectance method respectively. Positive matrix factorization (PMF) was utilized to identify the following eight sources; industrial emissions (11.4%), fresh sea salt (15.5%), diesel emissions (18.4%), biomass burning (9.5%), two stroke engines (5.1%), gasoline emissions (15.8%), aged sea salt (6.2%), and soil dust (17.7%). Source locations were verified by means of Conditional Probability Function (CPF) plots that utilize wind directions. The source contributions revealed the high influence of fossil fuel and biomass combustion on the air quality in Ashaiman. The presence of the harbor and the industries located at Tema were seen to have substantial impacts on respirable air particulate matter (APM) concentrations in Ashaiman. (c) Author(s) 2012. This work is distributed under the Creative Commons Attribution 3.0 License.