The extensions "Ozone Source Apportionment Technology" (OSAT) and the "Particulate Source Apportionment Technology" (PSAT) were used to study the photochemical air pollution in Medellin city (Colombia, South America). The OSAT tool allowed the tracking of source region and source category contributions to predicted grid cell ozone concentration. The model gave a clear picture of likely distribution of ozone and ozone precursors by source category and source region. On the other hand, PSAT provided source-category and geographic source apportionment of modeled particulate matter by individual species. The results were applied to support the reduction programs in the Clean Air Act for Medellin City. This is an abstract of a paper presented at the 102nd AWMA Annual Conference (Detroit, MI 6/16-19/2009).