Based on hourly elemental and gaseous data, three kinds of PMF-GAS methods were developed to have further and detailed insights into PM2.5 and gaseous sources, which play critical roles in their effective control. According to the results of PMF-GAS1, which were based on gaseous markers to enhance source discrimination, crustal dust, vehicular exhaust, coal combustion, sulfate and nitrate (CD1, VE1, CC1, SUL1 and NIT1) directly contributed 20%, 17%, 15%, 34% and 14% to PM2.5, respectively. Through the PMF-GAS2 which was based on sum of species and corresponding precursors to estimate the total influence, the total contributions of CD2, VE2 and CC2 to PM2.5 were quantified as 30%, 29% and 41%, respectively. PMF-GAS3 quantified the influence of reactions based on the relationships between species and precursors. The oxidation (OXI3) contributed 27% to PM2.5. NH4+ was mostly found in CD2 and CD3 but also in SUL1 and NIT1, implying that crustal dust can provide alkaline conditions for the formation of ammonium salts. High correlations were found among corresponding source contributions, but CD1 showed relatively weak links with CD2 and CD3 due to NH4+ in different factors. High map of BS runs implies stability of PMF-GAS results.