An indoor and outdoor source apportionment study was conducted to quantify fine particulate matter PP 205 sources. The data consist of mass and elemental composition of PM2.5 samples collected inside 70 smokers, 70 non-smokers homes, and at an outdoor site in Tehran, Isfahan and Gilan provinces, two communities participating in a large health effects study. The data were divided into winter and summer seasons and analyzed separately. The apportionment results were used to reconstruct the contribution of various sources to the measured PM2.5 mass concentrations. Tehran results show that sulfur-related, auto-related and soil sources contribute to PM2.5 levels indoors. In Isfahan, an outdoor composite source and soil impacts were identified during winter months. In summer, the resolved outdoor composite, sulfur-related and auto-related sources showed significant contributions to indoor PM2.5 mass. Additionally, a wood-smoke source was resolved during winter months in both the places. The PCA analyses of smokers homes show that the resolved tobacco smoke is the major contributing PM2.5 source
