Determination of Pahs in Smoke Generated from Different Woods: A Search for Greener Wood Fuel

Abstract

Most polycyclic aromatic hydrocarbons (PAHs) are carcinogenic to animals and humans and most of them are produced in the incomplete combustion of organic substances. However, smoke produced by some woods contain less PAHs than others. Different woods were used for this project in search of greener wood fuel.  A simple, less expensive, easily constructed steam extraction of the PAHs was carried out. This was followed by liquid-liquid extraction and analysis by HPLC-FLD. The qualitative analysis was effected by comparing the retention times of PAHs in the standard mixture with those in the smoke samples and the results show that all the analytes under investigation were found in the samples except fluoranthrene and chrysene. Terminalia superb does not produce phenanthrene. The complete combustion of 1g of the soft wood samples (Ficuscapensis, Ceibapentadra, Garcinia kola, Anthocleistavegilii, Terminalia superb, Symphoniaglobuliferal) gave a concentration range of 4.31 – 3.10 µg of PAHs while the complete combustion of 1g of the hard wood samples (KlanedoxiaGabonensis, VapacaGuiniensis, MagiferaIndica, Alstoniaboonei, Alchorniacordifolia, Terminalia iverensis, Lophiraalata) gavea concentration range of 2.78 – 1.21 µg of PAHs. Statistical t-test on the data show that the levels of PAHs in the hard wood samples were significantly different from the levels in the soft wood samples; suggesting that hard woods are generally better wood fuels than soft ones in respect of environmental issues.