The Malaysian Journal of Analytical Sciences Vol 11 No 1 (2007): 36 – 41

 

 

ALIPHATIC AND PAHs EMISSIONS FROM OPEN BURNING OF SELECTED TROPICAL WOODS

 

Tan Hock Seng¹, Norhayati Mohd Tahir^*1  and Mhd Radzi Abas²

 

¹Environmental Research Group (ERG), Department of Chemical Sciences, Faculty of Science and Technology

Kolej Universiti Sains dan Teknologi Malaysia, Mengabang Telipot, 21030 Kuala Terengganu

²Chemistry Department, University Malaya, 50603 Kuala Lumpur

 

*Corresponding author email: hayati@kustem.edu.my

 

Abstract

A study has been carried out to characterize hydrocarbons emitted from the burning of two wood samples  that is kulim (Scorodocarpus  spp.) and seraya (Shorea spp.).   The woods were burned and respective smoke aerosols  emitted  were sampled  using  high  volume  filtration  on  a  pre-cleaned  glass  fibre  filters  under  smouldering  and  flaming  conditions. Hydrocarbons were extracted  using dichloromethane as solvent and the extracts  fractionated on silica-alumina column. Detection  and  quantification  of  aliphatic  hydrocarbons  and  PAHs  compounds  were  carried  out  using  GC-MS. Results indicated that the major aliphatic hydrocarbons characterized from the smoke particles were straight n-alkanes in the range of C₁₈-C₃₆. Both samples exhibited an odd to even carbon predominance with carbon preference index (CPI) larger than 1. In general, CPI > 1 indicates n-alkanes contribution from epicuticular waxes and thus it can be concluded that this particular signature of terrestrial plant wax is retained despite the burning process. The total identified n-alkanes for kulim wood was 734 µgg^-1  with C_max  at C₂₇   and CPI of 1.10 while seraya wood yielded 113 µgg^-1 total identified n-alkanes with C_max of C₃₁ and CPI of 1.35. Results also indicated that burning resulted in the formation of significant amount of PAHs compounds in both the wood samples; total PAHs compounds emitted from kulim and seraya wood was 5870 µgg^-1  and  5810 µgg^-1, respectively. The  major PAHs compound exhibited in both wood samples were four rings  PAHs (e.g. fluoranthene and pyrene) with lesser amount of two to three (e.g. acenaphthylene) and five to  six rings PAHs (e.g. benzo(a)pyrene and benzo(g,h,i) perylene). In conclusion, burning of wood generated aliphatic and PAHs compounds but their distribution was influenced by the tree species .

 

Keywords: smoke aerosols, biomass, controlled burning, hydrocarbons, polycyclic aromatic hydrocarbons

 

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