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Performance Evaluation of the Empirical Kinetic Modeling Approach (EKMA)

  • J. Raul Martinez
  • Christopher Maxwell
  • Harold S. Javitz
  • Richard Bawol
Part of the NATO · Challenges of Modern Society book series (NATS, volume 3)

Abstract

The EKMA is a Lagrangian photochemical air quality simulation model that calculates ozone from its precursors: nonmethane hydrocarbons (NMHC) and nitrogen oxides (NOx). This study evaluated the performance of the EKMA when it is used to estimate the maximum ozone concentration that can occur in an urban area and its environs. The evaluation was conducted using data for five U.S. cities. This paper reports the results for St. Louis, Missouri.

A novel statistical evaluation procedure was developed to measure the accuracy of the EKMA ozone estimates. The accuracy parameter is defined as the ratio of observed to estimated ozone. Associated with this ratio is an accuracy probability, which is defined as the probability that the ratio lies within a predefined percent (e.g., ±20 percent) of unity, a unit value of the ratio denoting perfect agreement between observation and prediction. Equations were derived that express the ratio as a function of NMHC and NOx. The evaluation procedure thus uses NMHC and NOx as inputs to calculate the accuracy probability of the EKMA ozone estimate. The full range of accuracy probabilities associated with the EKMA ozone estimates is displayed in graphical form on the NMHC-NOx plane.

Keywords

Shade Area Maximum Daily Temperature Accuracy Probability Photochemical Oxidant Maximum Ozone 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

  1. Dodge, M.C., 1977, “Effect of Selected Parameters on Predictions of a Photochemical Model,” EPA–600/3–77–048 (June).Google Scholar
  2. Martinez, J.R., C. Maxwell, H.S. Javitz, and R. Bawol, 1981, “Evaluation of the Empirical Kinetic Modeling Approach (EKMA),” Draft Final Report, SRI Project 7938, SRI International, Menlo Park, California (July).Google Scholar
  3. U.S. Environmental Protection Agency, 1977, “Uses, Limitations, and Technical Basis of Procedures for Quantifying Relationships Between Photochemical Oxidants and Precursors,” EPA–450/2–77–021a (November).Google Scholar
  4. U.S. Environmental Protection Agency, 1978, “Procedures for Quantifying Relationships Between Photochemical Oxidants and Precursors: Supporting Documentation,” EPA–450/2–77–021b (February).Google Scholar
  5. U.S. Environmental Protection Agency, 1980, “Guideline for Use of City–Specific EKMA in Preparing Ozone SIPs,” EPA–450/4–80–027 (October).Google Scholar
  6. Trijonis, J. and D. Hunsaker, 1978, “Verification of the Isopleth Method for Relating Photochemical Oxidant to Precursors,” EPA–600/3–78–019 (February).Google Scholar
  7. Whitten, G.Z. and H. Hogo, 1978, “User’s Manual for Kinetics Model and Ozone Isopleth Plotting Package,” EPA–600/8–78–014a (July).Google Scholar

Copyright information

© Plenum Press, New York 1983

Authors and Affiliations

  • J. Raul Martinez
    • 1
  • Christopher Maxwell
    • 1
  • Harold S. Javitz
    • 1
  • Richard Bawol
    • 1
  1. 1.SRI InternationalMenlo ParkUSA

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