Sulfur dioxide (SO₂) emission reductions at the Tennessee Valley Authority (TVA) Cumberland fossil plant (CUF) at Cumberland City, Tennessee will have the concomitant benefit of reducing the formation of secondary sulfate aerosol in the Cumberland power plant plume. Therefore, primary sulfate emissions (i.e., SO₃/H₂SO₄) may now be comparable in mass and volume to secondary sulfate aerosols. For those units with relatively high NOx emissions, secondary nitrate particles could become the dominant contributor to fine particulate mass in scrubbed plumes. As part of an Interagency Agreement with NETL, TVA is carrying out an assessment of the impact of the installation of high-efficiency wet flue gas desulfurization and NOx control technology on primary and secondary fine particulate formation at the Cumberland power plant.

Data has been collected during the 1998 portion of the Cumberland Visible Emissions Study on the changes (and rates of changes where possible) in total mass, size distributions, and chemical composition of in-plume fine particles. This data will be used to evaluate emerging EPRI and EPA plume particle models. Additional data on concentrations of gaseous species in the CUF plume were also collected. These data will refine our knowledge of what factors most influence the fate of plume NOx, determine the efficiency of ozone formation in the plumes of large stationary sources, and help under-stand how that efficiency may change with the installation of NOx control technology. Another objective of this project is to identify the potential for changes in primary and secondary PM2.5 emissions from further NOx reductions at large power plants.