Application of the Pseudo-Deterministic Receptor Model to Resolve Power Plant Influences on Air Quality in Pittsburgh

A multivariate pseudo-deterministic receptor model was applied to determine emission and ambient source contributions rates of SO₂ and elements from four small coal-fired boilers influencing air quality at the Carnegie Mellon University (CMU) Supersite. The model was applied to ambient SO₂ and particle measurements, the latter, made every 30-min for 10 elements (Al, As, Cr, Cu, Fe, Mn, Ni, Pb, Se, and Zn) during a 12.5-h period on April 1, when winds blew from between 290–330° in which the four coal boilers are situated. Agreement between predicted and observed SO₂ concentrations was excellent (r of 0.92; and their ratio, 1.09 ± 0.22) when 4 emission sources were used in the model. Average ratios of predicted and observed concentrations for As, Cr, Cu, Ni, Pb, Se, and Zn varied from 0.97 ± 0.20 for Cr to 1.07 ± 0.44 for As. Performance indices for these elements were all well within acceptable ranges. Emission rate ratios of various metal species to Se predicted are similar for the three of the coal boilers, but differed substantially for the fourth, as expected for a boiler with minimal particle control technology. All are within the range derived from previous PDRM results and in-stack measurements (except Al) at 7 Eastern U.S. coal-fired power plants. The results suggest that the PDRM approach is applicable to a city encompassing complex topography and may successfully be applied using commonly available meteorological data.

This work was funded in part by United States Environmental Protection Agency under contract R82806101 as part of the Pittsburgh Air Quality Study (PAQS), and in part by the United States Environmental Protection Agency through grant/cooperative agreement (BSS R82806301) to the University of Maryland, College Park (UMCP). Nevertheless it has not been subjected to the Agency's required peer and policy review and therefore does not necessarily reflect the views of the Agency and no official endorsement should be inferred.

Notes

¹Derived from deconvolution of ambient concentration measurements near Tampa, FL, using the Pseudo-Deterministic Receptor Model.

²Derived from analysis of in-stack sampling of fine “fine” particles, except Mt. Tom ratios, which were drived from analyses of all in-stack particles.

³Electrostatic Precipitator.