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SIP suit reportReport on the Attainment Demonstration in the EPA's Proposed and Final Rules for the Baton Rouge SIP(G. Miller, Sept. 14, 1999) The proposed rule addresses the attainment demonstration in Section 6 of 63 FR 44192-02, and gives the 'Modeling Evaluation Summary' in Section 7. The final rule discusses the attainment demonstration in Section 2d of 64 FR 35930- 01 and gives the evaluation in section 2e. These rules were most assuredly written by the Air Planning Section at EPA's Region 6. This group has been putting out some notoriously poor work always deciding in favor of whatever the State wants. These proposed and final rules are no exception. The situation will be viewed more seriously and evaluated more critically at the EPA national level. Final Rule The evaluation of the attainment demonstration states that "two of the three episodes met or nearly met all the specified benchmark criteria." Since the statistical tests weren't passed the final rule goes on to say, "supplementary information provided by the State for consideration in the weight-of-evidence determination (i.e., mid- course review, severity of selected episodes, uncertainty in the boundary condition estimates, etc.) supported the modeled attainment demonstration." The final rule then states that the EPA has made a weight of evidence determination to conclude that the attainment demonstration was successful. The weight of evidence determination was based on "general trend data, which reflected reductions in monitored ozone values, precursor emissions, and total exceedence days since 1990." The EPA gives no statistical or graphical information in the final rule to support this argument. They do reference a "technical support document" for the proposed rule, but it doesn't appear to contain the statistical or graphical information to back up their decision. Figure 1. The number of exceedence days per year from 1990 to 1997. The line is a modified power law fit to the data.  An analysis of the monitored ozone values and total exceedence days shows the EPA's analysis to be incorrect. Figure 1 shows the number of exceedence days per year from 1990 to 1997. The data does show a slight downward trend for the entire period, but it has a pronounced upward trend from 1994 to 1997. Figure 2 shows the number of exceedence days from 1991 to 1998. This time frame encompasses all the years after the enactment of the 1990 Clean Air Act and for which complete data is available. This figure clearly shows the upward trend in exceedence days between 1991 and 1998. This indicates that the emissions reduction in the SIP are inadequate to provide for attainment of the ozone standard by the 1999 attainment date. Figure 2. The number of exceedence days per year from 1991 to 1998. The line is a modified power law fit of the data.  Further analysis of the ozone data shows that the total number of exceedences from 1990 to 1997 shows a downward trend, see Figure 3. However, this trend in the data is skewed due to a very bad year in 1990 and the figure shows that the number of exceedences per year has been relatively flat since 1991. Figure 3. The total number of exceedences per year from 1990 to 1997. The line is a modified power fit to the data.  Looking at the number of exceedences from 1991 to 1998 shows an increasing trend in exceedences throughout this period, see Figure 4. This also supports the conclusion that the emissions reductions in the SIP are inadequate to achieve the ozone standard at any time in the future. Figure 4. The total number of exceedences per year from 1991 to 1998. The line is a modified power law fit of the data.  An analysis of the maximum ozone reading per year is shown in Figure 5. This shows a slight downward trend in the data between 1990 and 1997, but a slight upward trend in the data from 1991 to 1998. Once the large distortion in 1990 is removed the data shows that there has been no improvement in the severity of the maximum ozone readings since 1991. Figure 5. Maximum ozone readings per year from 1990 to 1998. The solid line is a modified power law fit of the 1990 to 1997 data. The dashed line is a modified power law fit of the data from 1991 to 1998.  It should be noted that the EPA did not perform the trend analysis recommended in the "Guidance on Use of Modeled Results to Demonstrate Attainment of the Ozone NAAQS" (EPA-454/B-95-007). This is the EPA's primary trend analysis to be used in support of a weight of evidence determination. This trend analysis either wasn't performed by the DEQ or the EPA, or, more likely, was performed and simply not reported. Proposed Rule The language describing the support for the weight of evidence determination is similar to that in the final rule; "In determining whether the State's statistical approach and weightofevidence determination was adequate, EPA considered trend data, in particular, which reflect significant reductions in monitored ozone values, precurser emissions, etc. since 1990. For example, air quality in the Baton Rouge ozone nonattainment area has shown a steady improvement toward attaining the ozone NAAQS. The ozone design value has dropped significantly from the 1990 design level of 168 ppb. The current design value (based on 19951997 air quality data) is 139 ppb. (A historical account of the design values since 1990 is provided in the TSD to this proposed rulemaking.)" The statements again are not supported with any statistical or graphical information other than the design level values. Simply because the EPA states that the ozone situation is getting better doesn't make it true. Instead, the same graphical analysis of Figures 1 to 5 as done above shows that the ozone situation from 1991 to 1998 has gotten worse, not better. This also shows that the emissions reductions in the SIP will not provide for ozone attainment by the attainment deadline or at any time in the future. The design values have gotten better from 1990 to 1997. We don't have the design value data from 1991 to 1998, but it should show a leveling off around 1995 with little or no improvement out to 1998. Background An attainment demonstration is required by the 1990 Clean Air Act Amendments for ozone nonattainment areas in the serious category. The attainment demonstration requires that three ozone episodes be modeled to show that the emissions reductions in the State Implementation plan will be adequate to attain the ozone standard by November 15, 1999. The modeled episodes for the Baton Rouge are were for August 16, 1989, May 25, 1990 and August 19, 1993. The attainment demonstration consists of a three tests applied to each model. The first test, referred to as benchmark 1 by the EPA, is a compilation of all three models and was passed. The second test was failed by all three models. The EPA contends that the third test was not required for any of the models, with the August 19 model failing. Upon failure of one or more benchmark tests the EPA allows a weight of evidence determination to see if the area would be expected to achieve attainment despite the failure of the tests. The August 16 and May 25 models are close enough to warrant consideration of a weight of evidence determination, and could possibly pass if not for the poor record of ozone exceedences in the area in recent years. The August 19 model is too far from passing benchmarks two and three to have been considered in a weight of evidence determination. This didn't stop Region 6 from making one anyway and subsequently passing the attainment demonstration as meeting the requirements of the Clean Air Act. The EPA admits that the attainment demonstration models do not pass the EPA's own guideline tests. The do, however, claim that the models pass on a weight of evidence demonstration. It is this weight of evidence demonstration that will be the focus of the report. End of Report Back to Air Projects page.
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