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Grand Avenue Widening Project Environmental Impact Report Section 3.0 Long Term Air Quality Impacts Under Alternative I Local Area Air Ouality. The CALINE4 computer modeling results for the buildout year for the Grand Avenue widening, 2020, are shown in Table 3.4-3. The future CO modeling was conducted at the intersections of Grand Avenue with First, Fruit and Seventeenth Streets. The receptor locations used for the future CO modeling are the same receptor locations as for the modeling of existing CO levels, shown earlier in Figure 3.4-1. The future ambient background CO concentration levels are from the CEOA Air Quality Handbook. The future projected ambient CO levels for 2000 were used for this analysis because data is not available for 2020. Therefore, it is assumed that the background CO levels for 2000 are the same as 2020. This can be considered as the worst case scenario because background CO levels are projected to decrease steadily in future years. The future background levels, from the Anaheim monitoring station, are 9.5 ppm for one hour CO levels and 5.5 ppm for eight hour CO levels. The CO levels in Table 3.4-3 are totals of the background levels of CO coming into that area plus the CO levels generated by the local roads. The CALWFA CO modeling was conducted for two scenarios: the future No Project Alternative and the future With Project Alternative. As shown in Table 3.4-3, the future CO levels for the No Project Alternative are estimated to range between 9.7 and 11.3 parts per million (ppm) for one hour and between 6.8 and 7.9ppm for eight hours. The future CO levels associated with the proposed Grand Avenue widening project are expected to range between 9.5 and 11.0 ppm for one hour and between 6.7 and 7.7 ppm for eight hours. The future CO concentrations for both the project and No Project Alternatives are anticipated to be below the state and federal AAQS as shown in Table 3.4- 3. For these future scenarios, the CO levels during peak hour traffic for the future with project alternative are anticipated to be less than under the No Project Alternative. Under the proposed widening project, future CO levels are projected to be an average of 0.3 ppm less for one hour and 0.2 ppm for eight hours at the three receptor locations, compared to the No Project Alternative. The reductions in the future CO levels under the proposed project occur because the proposed widening project will help alleviate the heavy traffic congestion at intersections within the project limits. Without the proposed Grand Avenue widening, the intersection of Grand Avenue with First Street will operate at LOS D in 2020; the intersections at the I-5 northbound ramps, Seventeenth Street and Fourth Street will operate at LOS E; and the intersection with Fruit Street will operate at LOS C. The 2020 peak hour traffic at these intersections will be very congested. However, with the proposed Grand Avenue widening, the peak hour traffic on Grand Avenue, specifically at the I-5 northbound ramp and Santa Ana Boulevard will be improved to LOS C. The peak hour traffic on Grand at Fourth Street and Seventeenth Street will be improved to LOS D. The only intersection that will not be improved with project implementation is the southbound intersection at Santa Ana Boulevard where the exclusive dual right turn lanes will be converted to a single right tum lane and one through lane, to provide a third through lane. This conversion will result in the intersection performing at LOS F during PM peak hour. Under the no project condition it would perform at LOS D during PM peak hour. Refer to Section 3.5 (Transportation) for a detailed discussion on traffic. F.•IPROJ-ENVIGrand eirlNew Text - GrandlSection 3 SpIOSection 3.4.doc Page 3.4-11