Measurement of polycyclic aromatic hydrocarbons(PAHs) in ambient fine particulate matter using thermal desorption coupled with gas chromatography-mass spectrometry

Chemical composition is a key factor on the health effects of ambient fine particulate matter (i.e., PM 2.5 ), but so far evaluation of chemical component exposure to PM 2.5 is restricted by traditional analysis approach in epidemiological studies. To explore a highly efficient approach for the analysis of PM 2.5 components, in the present study we developed and optimized a method of two-step thermal desorption coupled with gas chromatography-mass spectrometry (TD-GC-MS) to determine particulate phase polycyclic aromatic hydrocarbons (PAHs). This optimized method was highly sensitive with method detection limits of 0.018 to 0.26 ng•m ^-3 when 0.28 m ³ PM 2.5 sample was applied. Parallel determination of standard reference materials (SRM, n=5) showed good reproducibility and high accuracy. PAHs levels measured with TD method were compared with those by classic Soxhlet extraction (SE). Good correlations were observed between these two approaches among most 3~5-ring PAHs; TD approach showed higher reliability for several species such as fluoranthene. Concentration of 12 measured PAHs during one-year period in Beijing ranged from 4.27 to 340 ng•m ^-3 , with much higher concentrations in the heating season than in the non-heating season. A positive matrix factorization (PMF) based source apportionment indicated that coal combustion was the major source during the heating season, while vehicle emission was the predominant one during the non-heating season. Finally we estimated the incremental lifetime cancer risk (ILCR) for adult residents, and it suggested that sources of vehicle emission and coal combustion should be controlled to reduce the risk of PAHs in PM 2.5 .

Duke Scholars

Author Yan Lin Environmental Natural Science