1

**Summary of WRAP Policy** 1. Pursuant to 40 CFR 51.309(d)(3), the WRAP directs its Technical Oversight Committee (TOC) to track emissions and to describe the tracking process in such a way that can be included in state and tribal implementation plans. At a min imum, using the most recent state emission inventories available, the TOC should produce a report for each five

- year implementation plan revision on the current and projected emissions in the clean air corridor and in areas outside the corridor and compare these emissions to a 1996 baseline for purposes of this section. 2. Pursuant to 40 CFR 51.309(d)(3)(i), the WRAP identifies one clean air corridor as shown in Figure 1. For ease of administration, the corridor's boundary follows county

lines. 3. Pursuant to 40 CFR 51.309(d)(3)(ii), the WRAP has examined patterns of growth in the corridor and finds that they are not causing significant emission increases that could have or are having visibility

impacts at one or more of the 16 Class Iareas. Nor, at this time , are such emission increases expected during the first planning period (2003

- 2018). Analy ses performed by

the Grand Can yon Visibility Transport Commission found that an increase of 25% in weighted emissions would result in a 0.7 dv reduction in visibilit y, whereas the weighted emission increase expected by 2018 is onl y 4%. 4. Pursuant to 40 CFR 51.309(d)(3)(iii), the WRAP has examined emissions growth in areas outside the corridor and finds that significant emissions growth is not occurring that could begin or is beginning to impair the qualit y of the air in the corridor and thereb y lead to visibility

degradation for the least impaired day s in one or more of the 16 Class I areas. 5. Since impairment of air quality in clean air corridors has not been identified pursuant to 40 CFR 51.309(d)(3)(ii) and (iii), the WRAP finds no requirement under 40 CFR 51.309(d)(3)(iv) for further visibility impact anal ysis or additional emission reduction measures until at least the next SI P revision (2008). However, the WRAP enc ourages its appropriate technical activities

- such as the Causes of Haze report

- to take into account the assessment and protection of clean air corridors. 6. Pursuant to 40 CFR 51.309(d)(3)(v), the WRAP finds no other clean air corridors bey ond the corrid or identified in Figure 1. **Conclusion** While the area to the northwest of the Colorado Plateau delivers clean air to the Plateau on the cleanest day s, emissions from throughout much of the region affect the Class I areas on the Plateau. Thus, emissions throughout the WRAP region will be tracked carefully . Ongoing WRAP efforts to improve the quality of inventories and the models used to make projections, and to produce a periodic Causes of Haze report, will bring increased understanding of the role that c lean air corridors play in protecting the cleanest day s. In the final analy sis, the indicator of success or failure will be whether the measured light extinction at the Class I areas on the2

Colorado Plateau improves or declines on the cleanest days. An y indication of deterioration on the cleanest day s should trigger an immediate investigation of the cause, as well as efforts to correct the problem.