Measurement of Polycyclic Aromatic Hydrocarbons Collected from Aerosols in Ambient Stockton Air

Introduction: PAHs are known carcinogens produced in abundance as byproducts of combustion. By quantifying the concentration of PAHs in the air, this data can be used to determine if levels of PAH in the atmosphere is high enough to be toxic to humans as well as other living creatures. Using Gas Chromatography/Mass Spectrometry (GC/MS), 16 common PAHs can be quantified in aerosols collected in ambient Stockton air. Methods: Multiple serial dilutions were used to obtain concentrations between 0.5 to 5 μg/mL from a 100μg/mL standard of PAHs. These standards were then analyzed using GC/MS in order to identify the retention times of the PAHs from GC, and to characterize the mass spectral response to identify the compound. Aerosol samples were collected from the air using a micro-orifice impactor (MOUDI). PAHs in the sample were identified and quantified through GC/MS. Results: An approximate retention time for each of the 16 PAHs was obtained with the set parameters ran on the GC/MS. Calibration curves were then constructed from the data for each of the PAHs in order to quantify the unknown samples collected through the MOUDI. The calibration curves obtained were strongly linear, indicating that the concentration range was within the linear range of the instrument. Furthermore, it was observed that PAHs undergo very little fragmentation due to their stable structure. Quantifying the levels of PAHs in the ambient air is ongoing. Significance: To determine if PAH levels in ambient Stockton air are under toxicity levels