Twenty Four-Hour PC-BOSS Air-Monitoring Results from the NETL Fine-Particulate Sampling Site in Pittsburgh, Pennsylvania: An Annual Perspective

Abstract

The concentration and composition of PM _2.5 from May to September of 2000 and monthly trends in ambient fine-particulate material concentrations from October 1999 through December 2000 at the National Energy Technology Laboratory's airmonitoring site in Pittsburgh are reported. Twenty four-hour integrated samples were collected using the Particle Concentrator-Brigham Young University Organic Sampling System (PC-BOSS), a multichannel integrated diffusion denuder sampler designed for routine determination of the chemical composition of ambient particulate matter. The fine-particulate pollutants determined were sulfate estimated as ammonium sulfate, nonvolatile organic material, semivolatile organic material lost from particles during sampling, elemental carbon, nitrate estimated as ammonium nitrate, including ammonium nitrate lost from particles during sampling and elemental content determined by PIXE (for a limited number of samples). Episodes with elevated sulfate and organic material (both semivolatile and nonvolatile) concentrations were seen throughout this period. For the purpose of this discussion, an episode was defined as all times when 3 h average TEOM monitor PM _2.5 concentrations exceeded 30 μg/m³. The use of estimated back-trajectories indicated that during the periods for which these elevated concentrations were observed, pollutants were transported predominantly from the Southwest from the Ohio River Valley to the sampling site. For days when fine particulate episodes occurred, back-trajectory computations were derived for time intervals for which PM _2.5 TEOM concentrations exceeded 30 μg/m³. However, for nonepisode days, back trajectories were computed over a 24 h period. Average PC-BOSS–constructed PM _2.5 concentration (including semivolatile components lost from particles during sampling) for the period from October 1999 through December 2000 was 19 μg/m ³ , excluding crustal material concentration.

Acknowledgments

The participation of Brigham Young University personnel was funded under a University Coal Research Grant # DE-FG26-99FT40581 from the United States Department of Energy, National Energy Technology Laboratory to Brigham Young University. We express sincere thanks to the Office of Science and Technology of the National Energy Technology Laboratory of the United States Department of Energy for continuing financial support for this project. We also express our appreciation to NETL staff Richard R. Anderson, Donald V. Martello, Paul C. Rohar, and Karl Waldner for their technical and field support and for use of data from the collocated TEOM and FRM monitors. Sincere thanks is also expressed to the Air Resources Laboratory of the National Oceanic Atmospheric Administration (NOAA) for permission to access the HYSPLIT transport and dispersion model on the NOAA Air Resources Laboratory's READY web server.

Reference to this report to any specific commercial product, process, or service is to facilitate understanding and does not necessarily imply its endorsement or favoring by the United States Department of Energy.

Notes

^a For calculated intercept.

^b For zero intercept.