The polycyclic aromatic hydrocarbon (PAH), elemental composition and toxicity of particulate matter from the exhaust of public utility vehicles (PUVs) fueled by commercial petroleum coco-biodiesel blend, were examined and compared with that from the exhaust of PUVs fueled by unblended petroleum diesel. FAME (Fatty Acid Methyl Ester) analysis of the commercial diesel/biodiesel blend and of a pure biodiesel sample was done to ascertain the presence of biodiesel in the commercial blend. NO2 from the exhaust vapor phase was likewise also compared for the two types of fuel. PAHs in particulate matter obtained by filter sampling and from tailpipe soot were analyzed by GC-MS (gas chromatography mass spectrometry). NO2 was analyzed by visible spectrophotometry, XRF (x-ray fluorescence spectrometry) was used for elemental analysis, and toxicological analysis was done using the Zebrafish Egg Assay Test. A general tentative conclusion from the results point to minimal difference between pure diesel and the 1% diesel/biodiesel blend (when used as fuel for PUVs) in terms of engine exhaust impact on air quality, except perhaps for PAH levels to some extent.