AAAR 33rd Annual Conference
October 20 - October 24, 2014
Rosen Shingle Creek
Orlando, Florida, USA
Abstract View
Comparison of Near-Roadway PAH Measurements via Multiple Methods
STEVEN BROWN, David Olson, Taehyoung Lee, Paul Roberts, Gary Norris, Jeffrey Collett, Sonoma Technology, Inc
Abstract Number: 318 Working Group: Carbonaceous Aerosols in the Atmosphere
Abstract We measured polycyclic aromatic hydrocarbon (PAH) concentrations at Fyfe Elementary School, 18 m from the US 95 freeway soundwall, in Las Vegas, Nevada, during January 2008. We collected PAH data via three methods: (1) from a high-resolution aerosol mass spectrometer (HR-AMS), at 2-minute resolution, termed APAH; (2) from a Photoelectric Aerosol Sensor (PAS) instrument, at 5-minute resolution, starting January 15, 2008, termed PPAH; and (3) from gas chromatography-mass spectroscopy (GC-MS) analysis of extracts from quartz fiber filters collected at various times during January 2008, termed FPAH. PPAH data showed a similar pattern to black carbon (BC) (r2=0.86), while APAH data were more similar to organic matter (OM) (r2=0.79). There was modest agreement between PPAH and APAH measurements (r2=0.49). Somewhat surprisingly, neither PPAH nor APAH showed a good correlation with hydrocarbon-like organic aerosol (HOA), despite the fact that the PAHs originated from primary emissions, similar in concept to what HOA represents. Of 26 filter samples, 17 had both coincident PPAH and APAH measurements, while an additional 9 filter samples had coincident APAH measurements. Neither PPAH nor APAH measurements compared well with the sum of total measured FPAH or of total measured hopanes. APAH had a high correlation with chrysene (r=0.80) and modest correlation with benzo(b)fluoranthene (r=0.69) and benzo(e)pyrene (r=0.66). PPAH did not have a correlation higher than 0.48 with any individual FPAH. Results indicate that PPAH measurements are more closely related to BC concentrations than OM, APAH, or specific FPAHs, while APAHs are closely related to chysene concentrations. PAH measurements correlated modestly with hopanes and levoglucosan, indicating PAH are from a mix of mobile, biomass burning, and other possible urban sources.