Source Diagnostics of Polycyclic Aromatic Hydrocarbons Based on Species Ratios:  A Multimedia Approach

Abstract

Often, the sources of polycyclic aromatic hydrocarbons (PAHs) in environmental media can be identified by comparing the ratios of concentrations of selected pairs of PAH congeners in the source emissions to the ratios in the contaminated environmental media. However, these ratios can be altered significantly due to differences in the transport of the PAH compounds in a multimedia environment. To examine such changes, a fugacity model was applied to PAH ratios in a model environment. A linear relationship between the rate of emission and the bulk media concentration was identified for each PAH compound in an environmental medium at steady state and was quantified by a receptor-to-source ratio (RRS). It was demonstrated that the RRS values of the two congeners usually differ significantly. Consequentially, PAH ratios changed remarkably from the source emissions to various environmental media. A site-specific rectification factor (RF) was defined as the ratio of the two RRS values of the paired congeners for a specific PAH ratio in a given medium, which can be applied to account for the ratio changes in a multimedia environment. The PAH ratio changes were further verified with the surface soil data collected from Tianjin, China, and the observed changes of PAH ratios were compared favorably with the model predictions. The sensitivity analysis revealed that PAH ratios of the low molecular weight compounds were less stable. The most influential parameters controlling PAH ratios were those pertaining to dry precipitation, surface-to-air diffusion, degradation in air and water, and exchange between water and sediment.

Polycyclic aromatic hydrocarbons (PAHs) in continental shelf sediment of China: Implications for anthropogenic influences on coastal marine environment

“…2). However, such a pattern was not coherent with that of IcdP/ (IcdP þ BghiP), suggesting that different PAH compounds underwent different degradation pathways from source to receptor (Zhang et al, 2005). This may be why the PAH diagnostic ratios in coastal marine sediments off China deviated from those of typical combustion sources (Fig.…”

The Effects of Height on the Accumulation of n-Alkanes and Polycyclic Aromatic Hydrocarbons (PAHs) in Air-Conditioning Filter Dust from High-Rise Apartments

“…Therefore, the identification of the sources of residual PAHs in ACFD remained difficult, possibly due to the change in the diagnostic ratios during the transportation and accumulation. Previous studies indicated that subtle variation in the physicochemical properties of the paired PAH species would alter the ratios from sources to receptors (Schauer et al, 1996;Zhang et al, 2005). For example, Ant was more susceptible to degradation than Phe, resulting in a reduced Ant/(Ant + Phe) ratio in pine needles (Hwang et al, 2003).…”

Analysis of polycyclic aromatic hydrocarbons in atmospheric particulate samples by microwave‐assisted extraction and liquid chromatography

“…PAHs are produced mainly by high-temperature reactions, such as incomplete combustion and pyrolysis of fossil fuels and biomasses [3,4]. Major sources of PAHs in urban areas include automobile traffic, domestic heating, thermal power stations, and industrial emissions [5].…”