Toxicological Evaluation of Realistic Emission Source Aerosols (TERESA)—Power plant studies: assessment of breathing pattern

Abstract

Our approach to study multi-pollutant aerosols isolates a single emissions source, evaluates the toxicity of primary and secondary particles derived from this source, and simulates chemical reactions that occur in the atmosphere after emission. Three U.S. coal-fired power plants utilizing different coals and with different emission controls were evaluated. Secondary organic aerosol (SOA) derived from α-pinene and/or ammonia was added in some experiments. Male Sprague-Dawley rats were exposed for 6 h to filtered air or different atmospheric mixtures. Scenarios studied at each plant included the following: primary particles (P); secondary (oxidized) particles (PO); oxidized particles + SOA (POS); and oxidized and neutralized particles + SOA (PONS); additional control scenarios were also studied. Continuous respiratory data were obtained during exposures using whole body plethysmography chambers. Of the 12 respiratory outcomes assessed, each had statistically significant changes at some plant and with some of the 4 scenarios. The most robust outcomes were found with exposure to the PO scenario (increased respiratory frequency with decreases in inspiratory and expiratory time); and the PONS scenario (decreased peak expiratory flow and expiratory flow at 50%). PONS findings were most strongly associated with ammonium, neutralized sulfate, and elemental carbon (EC) in univariate analyses, but only with EC in multivariate analyses. Control scenario O (oxidized without primary particles) had similar changes to PO. Adjusted R² analyses showed that scenario was a better predictor of respiratory responses than individual components, suggesting that the complex atmospheric mixture was responsible for respiratory effects.

Keywords::

• Respiratory function
• particulate matter
• ambient particles
• power plant emissions
• aerosol sources
• pollution sources
• breathing pattern
• respiratory mechanics

Acknowledgments

The authors thank the local universities, veterinary clinics, and suppliers who made an extraordinary effort to make a logistically very complex project possible.

Declaration of interest

This project was supported by the Electric Power Research Institute (Contract EP-P10983/C5530/56546), the U.S. Environmental Protection Agency Center for Particle Health Effects at the Harvard School of Public Health (grant R827353), and the Harvard NIEHS Center for Environmental Health (grant ES00002). This work was also prepared with the support of the U.S. Department of Energy (DOE) under award DE-FC26-03NT41902, and a grant from the State of Wisconsin. However, any opinions, findings, conclusions, or recommendations expressed herein are those of the authors, and do not necessarily reflect the views of the U.S. EPA or DOE. The Electric Power Research Institute (EPRI) employs Annette C. Rohr.