This thesis investigated the sources contributing to the organic carbon fraction of quasi-UFP (here PM0.36), itsseasonal variation and temporal-spatial variability. An in-situ derivatization thermal desorption gas chromatography time-of-flight mass spectrometry method was applied to PM0.36 for simultaneous quantification of primary andorganic markers. 5 sources including both primary and secondary sources were resolved by positive matrixfactorization (PMF) modeling based on measured organic species.