Forensic Characterization of Polycyclic Aromatic Hydrocarbons and Hopanes in Aerosols from Peninsular Malaysia

Abstract

A forensic study on the characterization of polycyclic aromatic hydrocarbons (PAHs) and hopanes in atmospheric aerosols has been carried out on nine locations in peninsular Malaysia in July 2006. There were 18 individual PAHs and 16 individual hopanes detected in the samples. Total PAH concentrations ranged from 0.58 to 10.49 ng/m³, and hopanes ranged from 1.62 to 10.49 ng/m³. Source identification using diagnostic ratios suggests that the biomass burning and vehicular emissions are the main sources of PAHs in the samples. Additionally, the strong influence of crankcase oil incorporated in street dust was identified pointing out a significant source of hopanes in the study area.

Keywords:

• diagnostic ratios
• biomass burning
• vehicular emission
• crankcase oil
• street dust

Acknowledgement

This project was supported by the government of Malaysia through MOSTI grant No. 5450100. The cooperation of the Malaysia Meteorological Service staff is greatly appreciated. We thank graduate students who directly and indirectly helped in this project.

Notes

a: Volume of collected air over 24 hours

b: Concentrations of total suspended particulates in sampling stations. Data from Bahry et al. (2008).

^a Abbreviation for PAHs compounds in this study.

^b Total PAHs = Sum of concentration of dibenzothiophene + phenanthrene + anthracene + 3-methylphenanthrene + 2-methylphenanthrene +

^c MP/P ratio = a ratio of the sum of 3-methylphenanthrene + 2-methylphenanthrene + 9-methylphenanthrene +1-methylphenanthrene to phenanthrene

^d LMW/HMW ratio = a ratio of the sum of dibenzothiophene + phenanthrene + anthracene + 3-methylphenanthrene + 2-methylphenanthrene +

^e Flu/(Flu+Pyr) ratio = a ratio of fluoranthene relative to the sum of fluoranthene + pyrene.

^f BeP/(BeP+BaP) ratio = a ratio of benzo(e)pyrene relative to the sum of benzo(e)pyrene + benzo(a)pyrene.

^g Phe/(Phe+Ant) ratio = a ratio of phenanthrene relative to the sum of phenanthrene + anthracene.

^h Sum of LMW = sum of dibenzothiophene + phenanthrene + anthracene + 3-methylphenanthrene + 2-methylphenanthrene + 2-methylanthracene + 9-methylphenanthrene + 1-methylphenanthrene + fluoranthene + Pyrene.

ⁱ Sum of HMW = sum of 1-methylpyrene + benzo(a)anthracene + chrysene + benzo(k)fluoranthene + benzo(e)acephenanthrylene + benzo(e)pyrene + benzo(a)pyrene + dibenzo(a,h)anthracene.

^a Abbreviation for hopane compounds in this study.

^b Total hopane = Sum of triterpanes. Ts: 18α (H), 21β (H)-22, 29, 30-trisnorneohopane, Tm: 17α (H), 21β (H)- 22, 29, 30-trisnorhopane, C₂₉, 17α : 17α (H), 21β (H)-norhopane, C₂₉, 17β: 17β (H), 21α (H)-norhopane, C₃₀, 17α : 17α (H), 21β (H)-hopane, C₃₀, 17 β : 17β (H), 21α (H)-hopane, C₃₁- C₃₅ homohopanes consisting of C₃₁- C₃₅ carbons with S and R stereo-isomers at the 22 carbon.

^c T PAHs/C30, 17α = a ratio of total PAHs relative to 17α (H), 21β (H)-hopane.

^d C29/C30 = a ratio of 17α (H), 21β (H)-norhopane to 17α (H), 21β (H)-hopane.

^e C31–C35/ C30 = a ratio of sum of C31 homohopane to C35 homohopane relative to C30 hopane.