Note: Modeled using (a) the current run-up areas; (b) the Z1 run-up areas; and (c) the Z2 run-up areas. Hangar/maintenance area engine testing emissions were excluded from this analysis.
Moving the run-up areas inward along the runways also increased the total area with modeled concentrations over 10 ng/m3; however, given the reduction in maximum modeled impacts, these results suggest that there could be substantial benefit to moving the run-up areas to the Z1 locations if the base case hotspot concentrations— which are about one-third of the Pb NAAQS of 150 ng/m3—were of concern.
Concentrations are much higher along the western runway because it is the primary runway used for conventional takeoffs and landings, rather than touch-and-goes and taxibacks. The eastern runway is generally used for flight training with planes performing touch-and-goes and taxibacks, which do not include run-ups. More than 90% of takeoffs with associated run-ups were attributed to the western runway. Thus, another mitigation strategy could be redistributing some of the run-ups adjacent to the western runway to the run-up area adjacent to the eastern runway. This strategy was not examined.
Santa Monica Airport
Figure 12 shows the locations of the primary run-up area at SMO (NE Orig) as well as two alternative areas approximately 80 meters (NE Z1) and 160 meters (NE Z2) to the southwest of the current run-up area. Similar to RVS, the alternative run-up areas were shifted along the taxiways more towards the middle of the airport, moving emissions away from the takeoff area. Like at RVS, new run-up areas were kept the same size and shape as the original areas.
Figure 12
Map of SMO with Current and Hypothetical Modeled Run-up Locations
Hourly concentrations were modeled using AERMOD and the highest three-month rolling average hotspot was observed for November–January with a Pb concentration value of 90 ng/m3, which is 60% of the Pb NAAQS. Figure 13 shows the concentration field for this three-month average for (a) the base-case scenario of using the original run-up area; (b) the Z1 run-up area; and (c) the Z2 run-up area. Compared to taxiways and takeoffs (34%, 7%), run‑up areas (54%) had a relatively high contribution to the maximum modeled three-month average Pb concentration across the SMO airport footprint. The counterfactual of no run-up emissions was also modeled with a concentration maximum of 58 ng/m3, a 35% reduction from the base case.
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