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Grand Avenue Widening Project Environmental Impact Report Section 3.0 The future with project CO modeling results in Table 3.4-3 can also be compared with the existing CO levels shown earlier in Table 3.4-2. As shown, the future with project CO concentration levels will essentially be lower than the existing CO levels. The future CO concentration levels will be reduced an average 0.9 ppm for one hour CO and 0.5 ppm for eight hours at the three intersections assuming implementation of the proposed Grand Avenue widening. This is mainly due to this proposed widening project, the decrease in future background CO concentration levels and the anticipated decrease in the vehicular emission factors (version MVEI7G). In general, the background CO concentration and the vehicular emission factors are projected to decrease steadily in future years. The future contribution of the local traffic will actually increase due to an increase in traffic volumes, but this will be more than offset by the decrease in background CO levels and vehicular emission factors. In addition, the proposed widening project will alleviate the traffic congestion at these intersections and, therefore, the future CO levels are also anticipated to be reduced. TABLE 3.4-3 WORST CASE PROJECTIONS OF CARBON MONOXIDE CONCENTRATIONS FOR 2020 Receptor Locations Future Carbon Monoxide Concentrations No Project m With Project m 1 hour 8 hours 1 hour 8 hours 1. N.W. Grand Avenue/First Street 9.7 6.8 9.5 6.7 2. S.W. Grand Avenue/Fruit Street 11.3 7.9 11.0 7.7 residential 3. S.W. Grand Avenue/17s Sheet 10.8 7.6 10.6 7.4 Summary of Carbon Monoxide State No. of Sites No. of Sites No. of Sites No. of Sites Standards Exceedances Exceeding Exceeding Exceeding Exceeding 20 Pum 9 pLm 20 pnm 9 Pool 0 0 0 0 In summary, Alternative 1 will not result in adverse impacts on local air quality and will contribute to a reduction in CO levels for the one and eight hour periods, compared to both existing conditions and the future No Project Alternative. Regional Air Quality. Increases in CO levels in the region compared to existing conditions were projected with and without the proposed Grand Avenue widening. Under the No Project Alternative, future traffic at the intersections along Grand Avenue will be very congested. During the peak hour, traffic demand on Grand Avenue will be well above the capacity of this street, especially at First Street, Santa Ana Boulevard, Washington Place and Seventeenth Street. With the proposed Grand Avenue widening, air quality is projected to improve since this project will alleviate heavy traffic congestion at these intersections. It is anticipated that, with the implementation of the proposed Grand Avenue widening, regional CO emissions will be reduced with respect to the No Project Alternative although the amount of this emission reduction can not be quantified. In summary, the proposed Grand Avenue widening would beneficially affect regional air quality. F: IPROJ-ENMGrand eirlNew Text - Gran&Section 3 SplitlSection 3.4.doc Page 3.4-12