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AMD NOX REDUCTION IMPACTS
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.
This is the first phase of a potentially multi-phase project aimed at identifying scientific methodologies that will lead to the development of innnovative analytical tools supporting the analysis of control strategy effectiveness, namely. accountabilty. Significant reductions in NOx emissions from stationary sources have occurred in the Eastern USA and additional reductions are anticipated in the future. These emission reductions have been required to reduce the troposheric ozone levels based primarily on computer modeling. The NOx RACT rule (NE OTR), CAAA Title IV, NOx SIP call, and the Section 126 rule all require NOx emission reductions throughout the Eastern USA from major sources. In addition, significant future reductions are expected from mobile sources, diesel engine rules, and the Clear Skies initiative or CAIR. Given the significant costs for these emission control measures, it is important to demostrate the effectiveness of these rules through analysis of modeling outputs and observations and our track progress in improving air quality.
Record Details:Record Type: PROJECT
Organization:U.S. ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF RESEARCH AND DEVELOPMENT
NATIONAL EXPOSURE RESEARCH LABORATORY
ATMOSPHERIC MODELING DIVISION
MODEL EVALUATION AND APPLIED RESEARCH BRANCH