This paper evaluates the effects of long-range transport patterns of air trajec- tories arriving at a rural ground based station, ICIPE Mbita 1125 meters above mean sea level. Mass concentration data of fine mode AOD, coarse mode AOD and fine mode fraction AOD were combined with back-trajectory clus- ter analysis. The Potential Source Contribution Function (PSCF) model and Concentration-Weighted Trajectory (CWT) method were used to evaluate the transport pathways and Potential Source Areas (PSA) affecting AOD loadings in western parts of Kenya during wet (MAM) and dry (JJA) seasons. The main sources and paths of advection to source and receptor regions and its relation to AOD concentration were identified. Using these methods, the Geographic Information System (GIS) based software and MeteoInfo was used for query and computation of potential source contribution function and concentration weighted trajectory analyses when the measurement data were included. The results for both PSCF and CPF were sufficient indicators that pollutants ori- ginated from two main sources, that is, northeastern and southeast directions from the site.