The Malaysian Journal of Analytical Sciences Vol 11 No 1 (2007): 29 – 35

 

 

HYDROCARBONS IN SMOKE AEROSOLS FROM CONTROLLED BURNING OF MANGIFERA FOETIDA LITTER FALLS

AND PANICUM REPENS

 

Tay Joo Hui¹, Tan Hock Seng¹, Norhayati Mohd Tahir* ¹and 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

²  Chemistry Department, University Malaya,

50603 Kuala Lumpur

 

*Corresponding author: hayati@kustem.edu.my

 

Abstract

A study has been carried out to characterize hydrocarbons emitted from the burning of two typical garden wastes, bachang (Mangifera foetida) litter falls and grass (panicum repens). The biomass samples were burned and their respective smoke particulate emitted was sampled using high volume sampler fitted with pre-cleaned glass fibre filters under smouldering and flaming conditions. Hydrocarbons were extracted  using  dichloromethane- methanol mixture 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.  For comparison, hydrocarbons in fresh unburnt bachang litter falls and grass were also analyzed for aliphatic and PAHs content. Result indicated that the major components in the aliphatic fraction for all samples were n- alkane compounds which exhibited a saw-tooth pattern that is characteristic of a biogenic origin. The major components in this aliphatic fraction for smoke particulate matters were  n-alkanes in the range of C₁₂-C₃₆,  with an odd to even carbon predominance with CPI values ranging from 2.89-4.32 and C_max generally at C₃₁; total identified n- alkanes for these samples ranged from 221-939 µgg^-1. On the other hand, hydrocarbons present in the fresh unburnt bachang litter  falls  and grass ranged from C₁₂-C₃₆   with C₂₇ and C₃₃ species dominating and CPI value of 4.5 and 23.1, respectively; total identified n- alkanes were significantly higher (1530-33000 µgg^-1) than those found in smoke aerosols   In general, CPI > 1 indicates n-alkanes contribution from epicuticular waxes thus it could be concluded that, even though the overall signature of the source of n-alkanes is maintained, burning seems to alter the distribution of aliphatic hydrocarbon  emitted  accompanied with a decrease in the CPI values and shifting in C_max. In addition, results also indicated that burning resulted in the formation of many PAHs compounds in all smoke aerosols samples with total PAHs concentration ranging from 187-296 µgg^-1. Fresh unburnt bachang litter falls and grass on the other hand did not exhibit any PAHs compound, which clearly indicated that PAHs were generally generated from combustion process.

 

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

 

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