6 - GPA19-01; AA19-01_651 W SUNFLOWER AVENUE

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Legacy Sunflower Apartments Page 38 Mitigated Negative Declaration – March 14, 2019 Monitored Air Quality The air quality at a site is dependent on the regional air quality and local pollutant sources. Regional air quality is determined by the release of pollutants throughout the air basin. Estimates of the existing emissions in the Basin indicate that collectively, mobile sources account for 60 percent of the VOC, 90 percent of the NOx emissions, 95 percent of the CO emissions and 34 percent of directly emitted PM2.5, with another 13 percent of PM2.5 from road dust. The SCAQMD has divided the South Coast Air Basin into 38 air-monitoring areas with a designated ambient air monitoring station representative of each area. The project site is located in the Central Orange County Air Monitoring Area (Area 17), which is located in the central portion of Orange County and covers an area from Anaheim to the north, Cypress to the west, Tustin to the east, and Fountain Valley to the south. Data was taken from the Costa Mesa-Mesa Verde Drive (Costa Mesa Station) and Anaheim-Pampas Lane (Anaheim Station) which are the closest monitoring stations to the project site. Table 3 summarizes years 2015 through 2017 published monitoring data, which is the most recent 3- year period available. The data shows that during the past few years, the project area has exceeded the ozone and Particulate Matter (PM10 and PM2.5) standards. However, it should be noted that due to the air monitoring station distance from the project site, recorded air pollution levels at the air monitoring station reflect with varying degrees of accuracy the local air quality conditions at the project site. Table 3 Air Quality Monitoring Summary1 Pollutant Pollutant (Standard)2 Year 2015 2016 2017 Ozone: Maximum 1-Hour Concentration (ppm) 0.099 0.090 0.088 Days > CAAQS (0.09 ppm) 1 0 0 Maximum 8-Hour Concentration (ppm) 0.080 0.069 0.080 Days > NAAQS (0.070 ppm) 2 0 4 Days > CAAQS (0.070 ppm) 2 0 5 Carbon Monoxide: Maximum 8-Hour Concentration (ppm) * * * Days > CAAQS (9 ppm) 0 0 0 Days > NAAQS (9 ppm) 0 0 0 Nitrogen Dioxide: Maximum 1-Hour Concentration (ppm) 0.052 0.060 0.045 Days > CAAQS (0.18 ppm) 0 0 0 Inhalable Particulates (PM10):2 Maximum 24-Hour Concentration (µg/m3) 59.0 74.0 95.7 Days > NAAQS (150 µg/m3) 0 0 0 Days > CAAQS (50 µg/m3) 2 3 5 Annual Average (µg/m3) 25.5 27.5 26.9 Ultra-Fine Particulates (PM2.5):3 Maximum 24-Hour Concentration (µg/m3) 53.8 45.5 56.2 Days > NAAQS (35 µg/m3) 3 1 7 Annual Average (µg/m3) 14.7 9.4 * 6-60