High-Volume PUF versus Low-Volume PUF Sampling Comparison for Collecting Gas Plus Particulate Polycyclic Aromatic Hydrocarbons

A yearlong sampling program for PM2.5and semivolatile organic compounds (SVOCs) was conducted in 2000/2001 in Missoula, Montana by The University of Montana, Department of Chemistry. One aspect of this program was to investigate the SVOC fraction of the Missoula Valley PM2.5by evaluating a Federal Reference Method (FRM) PM2.5sampler modified with Polyurethane Foam (PUF) sorbent (PM2.5PUF). In addition, a method of comparison was made between sampling for SVOCs using this modified PM2.5PUF sampler and in using a high-volume PUF sampler (Hi-vol PUF) following EPA protocol. For this comparison, the quartz filter and PUF plugs were extracted together in the analysis of the PM2.5PUF and Hi-vol PUF samples, respectively. Results of this program showed that a trade off between Hi-vol PUF sampling and PM2.5PUF sampling was revealed. During the same sampling periods, the PM2.5PUF measured more of the lighter (smaller molecular weight) SVOCs in a side-by-side comparison with the Hi-vol PUF sampler, with much less volume of sample collected due to a lower flow rate. However, each 24 h Hi-vol PUF sample run provided enough material on which to conduct an SVOC analysis, avoiding the need to aggregate samples (or longer sampling periods) to meet analytical detection limits. In addition, the results presented here also raise important questions about the efficiency of existing PUF samplers (when using quartz filters and PUF sorbent media) in the accurate measurement of lower molecular weight particle and gas-phase SVOCs.