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RELATIONSHIPS BETWEEN NITROGEN OXIDE EMISSIONS FROM ELECTRICAL GENERATING UNITS IN THE U.S. AND METEOROLOGY
Citation:
PORTER, S., S.T. RAO, AND E. L. GEGO. RELATIONSHIPS BETWEEN NITROGEN OXIDE EMISSIONS FROM ELECTRICAL GENERATING UNITS IN THE U.S. AND METEOROLOGY . In Proceedings, NATO/CCMS 28th International Technical Meeting, Leipzig, GERMANY, May 15 - 19, 2006. Elsevier Science BV, Amsterdam, Netherlands, 793-794, (2006).
Impact/Purpose:
The framework of accountability is based on measuring environmental outcomes using an integrated environmental assessment model - - assessing and documenting relationships between emissions, air quality, atmospheric deposition, and effects to public health and ecosystems. Work in AMD will focus on relating changes in emissions to changes in environmental conditions prospectively, and the retrospective attribution of observable improvements in environmental conditions to specific emission control strategies.
1.Emission reductions observed in ambient air and atmospheric deposition
Since the 1990 Clean Air Act Amendments, a greater number of stationary sources of SO2 and NOx emissions have installed continuous emissions monitoring systems. Improved systems for tracking emissions from mobile sources have also been developed. At this level, an accountability framework provides a bridge between measured emission reductions and changes in the ambient environment. Resources under this initiative would be applied to analyze specific primary and transformed emission products in ambient air and in atmospheric deposition (e.g., nitrogen oxide, particle nitrate) over relevant geographic areas.
2.Predicted air quality and atmospheric deposition improvements
Resources would be applied to enhance the predictive capability to address whether emissions reductions have resulted in the expected improvements in air quality and deposition, for example:
Reduced ozone, PM2.5 concentrations
Reduced deposition of NOx transformations (e.g., wet and dry deposition of nitrate)
Diagnostic species (e.g., peroxides, nitric acid, ammonia) useful for model evaluations and interpreting dynamic changes in the atmosphere associated emissions reductions
In addition to assessing whether the improvements have occurred, this would also entail assessing whether these improvements can be attributed to specific emission control strategies.This team's objective is to research and develop analytical tools that will quantify the effect of regional NOx emission reductions on ambient air quality, thus providing a measure of control stategy accountability.
Description:
Nitrogen oxide (NOx) emissions from electrical generating units (EGUs) in the northeast US have declined dramatically during the past few years as a result of a series of air quality rules (RACT rule, Clean Air Act Amendments Title IV, and the NOx SIP call). Progress in reducing NOx emissions is evident in continuous NOx measurements collected by EGUs. These measurements are collected hourly from roughly 1,500 EGUs and are archived at EPA's Clean Air Market Division, (USEPA, 2006a). NOx data collected by EGUs also have value as a source of information important to air quality modeling. Declining NOx emissions are most evident during the summer ozone season when seasonal controls are in effect, and have occurred despite offsetting increases in heat input (HI), the energy content of fuel used to generate electricity (also archived by EPA's Clean Air Market Division). Weather indirectly affects NOx emissions (and therefore air quality) by influencing the amount of fuel used for cooling and heating. Here we examine time scales common to both HI and meteorology with the goal of improving the performance of air quality modeling and forecasting.