Use of Particle Bound Polycyclic Aromatic Hydrocarbons (PAHS) Diagnostic Ratios to Assess Pollution Sources: Universal or Local Application?
It has been proven that Particulate Matter (PM) influence both global climate and public health. For this reason, regulators have set standards for ambient PM concentration. Often, these standards are difficult to meet in large urban centres. As a result, Considerable effort is being put into the identification of the sources of pollution to tackle the problem at its origin.
Most anthropogenic PM is emitted from combustion sources. These combustion processes produce a range of particle bound PAHs which relative concentrations are characteristic of the source, fuel and combustion conditions. This is particularly the case for diesel engines, one of the major PM emitters in urban centres.
In this project, 40 PM samples were collected in Sydney and an additional 20 PM samples were received from Vietnam. After soxhlet-extraction in an organic solvent, the extracts were concentrated and analysed by GC/MS using internal deuterated standards to quantify 16 PAHs. The different diesel-specific ratios used in the literature were calculated. In order to assess the validity of these ratios, the PAHs concentrations of a previous NSW EPA study on diesel engines emission in Sydney were used to calculated the same ratios.
We found that, among the ratios used in the literature, some were more applicable than others to Sydney’s specific fuel and fleet conditions. For our sampling site in Sydney, we were able to link traffic influence with specific atmospheric conditions. For Vietnam, the conclusions were not as clear as there was no information on PAHs distribution at the source.