During the TexAQS II campaign in summer 2006 (08/07/06 - 09/30/06) continuous online measurements of speciated PANs, and C₂ - C₁₀ Volatile Organic Compounds (VOCs) were performed at the Moody Tower supersite on the University of Houston campus. In addition, offline canisters for the VOCs were sampled within the Houston-Galveston metropolitan area for determination of certain industrial, vehicular and biogenic fingerprints. Starting from the characterization of measured VOC source profiles, Positive Matrix Factorization (PMF) was applied to establish the source apportionment of ambient VOCs and thus to estimate the contributions of different sources in the formation of PANs. VOC fingerprint results obtained at the Moody Tower were (i) related to PAN data and (ii) allocated to their respective C-sources. The analyses of the measured compounds indicate complex mixtures from various sources. In order to distinguish anthropogenic and biogenic contributions to the formation of PANs, selected ratios among the PAN compounds and ratios of selected VOCs were used as indicators for the different precursor pools based on the obtained VOC fingerprints.