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ENVIRONMENTAL IMPACT REPORTADDENDUM Bristol Street Widening Project Warner Ave to Saint Andrew Place (Phase IV) TABLE 6 LOCALIZED SIGNIFICANCE THRESHOLDS ANALYSIS FOR CONSTRUCTION ACTIVITIES Intersection Hot -Spots While the proposed Project would not result in any direct sources of localized emissions due to the roadway street lighting being powered by electricity, changes in LOS or traffic volumes due to the project may cause indirect sources of localized emissions. While emissions of motor vehicles have improved due to more stringent vehicle emissions standards and the use of cleaner burning fuels, they continue to be the primary source of local emissions within the study area. Localized areas where ambient concentrations exceed national and /or state standards for CO are known as hotspots. The SCAQMD defines typical sensitive receptors as residences, schools, playgrounds, childcare centers, athletic facilities, long -term health care facilities, rehabilitation centers, convalescent centers, and retirement homes. Because CO is produced in greatest quantities from vehicle combustion and does not readily disperse into the atmosphere, adherence to AAQS is typically demonstrated through an analysis of localized CO concentrations. Areas of vehicle congestion have the potential to create pockets of CO called "hot spots." These pockets have the potential to exceed the state one -hour standard of 20 ppm or the eight -hour standard of 9.0 ppm. Note that the federal levels are based on one- and eight -hour standards of 35 and 9 ppm, respectively. Thus, an exceedance condition would occur based on the state standards before the federal standards. The following intersections were modeled for CO hotspots: Bristol Street and Warner Avenue Bristol Street and Glenwood Place Bristol Street and St. Andrew Place Bristol Street and W. Edinger Avenue As shown in Table 7, both the 1 -hour and 8 -hour CO concentrations at the intersections that were affected by the proposed project would be substantially below the California and federal ambient air quality standards for CO, potential CO impacts related to the project alternatives are below AAQS and would not result in a significant air quality impact from CO hotspots. ANA 305 -194 (PER 02) CSA (AUGUST 2014) 133867 YU 30 75C -46 LI UTA fi(Lf.ud) t)( Rl1Tl PMFlSE NOx CO PM10 PMze x r. r Demolition 61 40 4 3 Grading 52 30 5 4 Trenching 33 19 2 2 Paving 15 1 11 1 1 1 1 SCAQMD Threshold 183 1,253 13 7 Exceeds Threshold? No No No No Source: URS Corporation, January 2013. Intersection Hot -Spots While the proposed Project would not result in any direct sources of localized emissions due to the roadway street lighting being powered by electricity, changes in LOS or traffic volumes due to the project may cause indirect sources of localized emissions. While emissions of motor vehicles have improved due to more stringent vehicle emissions standards and the use of cleaner burning fuels, they continue to be the primary source of local emissions within the study area. Localized areas where ambient concentrations exceed national and /or state standards for CO are known as hotspots. The SCAQMD defines typical sensitive receptors as residences, schools, playgrounds, childcare centers, athletic facilities, long -term health care facilities, rehabilitation centers, convalescent centers, and retirement homes. Because CO is produced in greatest quantities from vehicle combustion and does not readily disperse into the atmosphere, adherence to AAQS is typically demonstrated through an analysis of localized CO concentrations. Areas of vehicle congestion have the potential to create pockets of CO called "hot spots." These pockets have the potential to exceed the state one -hour standard of 20 ppm or the eight -hour standard of 9.0 ppm. Note that the federal levels are based on one- and eight -hour standards of 35 and 9 ppm, respectively. Thus, an exceedance condition would occur based on the state standards before the federal standards. The following intersections were modeled for CO hotspots: Bristol Street and Warner Avenue Bristol Street and Glenwood Place Bristol Street and St. Andrew Place Bristol Street and W. Edinger Avenue As shown in Table 7, both the 1 -hour and 8 -hour CO concentrations at the intersections that were affected by the proposed project would be substantially below the California and federal ambient air quality standards for CO, potential CO impacts related to the project alternatives are below AAQS and would not result in a significant air quality impact from CO hotspots. ANA 305 -194 (PER 02) CSA (AUGUST 2014) 133867 YU 30 75C -46 City Council 17 – 185 3/4/2025