1. Consequence Analysis Robert Wu South Coast Air Quality Management District

2.  ~ 15 Million People  ~ 10,000 square miles  ~ 10 Million Vehicles  ~ 27,000 Permitted Facilities (60,000+ Permits)  Stagnant Weather Patterns  Nation’s Most Severe Air Pollution

3. Methods for the Consequence Analysis Develop set of matched pairs of meteorological sites. Run ISCST3 with 1981 AQMD met data. Run AERMOD with 2005-2007 met data developed by EnviroComp. Concentration data placed in Access database. Calculate AERMOD-to-ISCST3 ratios of peak predicted concentrations and segregate results.  by dispersion characteristics (i.e., rural or urban)  by source type  by averaging time  by meteorological site

4. Source Receptor Areas within the South Coast Air Basin

5. Locations of Available Monitoring Stations

6. Meteorological Site Pairs Locations Separation distance (km) Location Separation distance (km) Anaheim2.13Mission Viejo/El Toro1.45 Azusa0.10Pico Rivera1.09 Banning2.91Pomona0.00 Burbank1.16Palm Springs3.23 Downtown LA0.16Redlands0.89 Costa Mesa2.03Reseda0.25 Indio1.17Riverside4.71 La Habra0.10Santa Clarita/Newhall1.02 Long Beach0.03Upland2.06 Lynwood0.74West LA6.75

7. Comparison of Mean Wind Speeds 1981 vs. 2005-2007

8. Comparison of Light Wind Frequencies 1981 vs. 2005-2007

9. Simulation Comparisons Dispersion characteristics  Rural & urban Source Types  8 point sources, 5 volume sources, & 5 area sources Averaging times  1-hr, 3-hr, 8-hr, 24-hr, & period Meteorological site  20 pairs

10. Point Sources DescriptionQ (g/s) Height (m) Temp (K) Velocity (m/s) Diameter (m) ICE – 200 hp1362259.90.102 ICE – 550 hp1362273.10.152 Small Turbine17.6264744.620.99 Intermediate Turbine126.272128.033.57 Large Turbine154.8636518.26.1 R1401 – 14 ft stack14.27Ambient0.0011 R1401 – 24 ft stack17.32Ambient0.0011 R1401 – 49 ft stack114.94Ambient0.0011

11. Volume Sources Description Q (g/s) Height (m) σ y (m) σ z (m) R1401 – 1600 ft 2 ; 15 ft12.292.842.13 R1401 – 5000 ft 2 ; 15 ft12.295.012.13 R1401 – 5000 ft 2 ; 30 ft14.575.014.25 R1401 – 15000 ft 2 ; 30 ft14.578.684.25 R1401 – 45000 ft 2 ; 30 ft14.5715.044.25

12. Area Sources Description Q a (g/s-m 2 ) Height (m) Length (m) Width (m) σ zo (m) Ports HRA – Rail2.50E-03520 2.33 Ports HRA – Truck8.16E-04435 1.86 LST – 1 acre2.47E-04063.63 1 LST – 2 acres1.24E-04089.97 1 LST – 5 acres4.94E-050142.25 1

13. Overall Results StatisticRuralUrbanAll Data Mean ratio3.230.912.24 Standard deviation3.130.642.67 High ratio21.876.3721.87 Low ratio0.220.14

14. Distribution of Results

15. Results by Source Type Statistic RuralUrban PointAreaVolumePointAreaVolume Mean ratio4.242.571.110.801.290.77 Standard deviation 3.860.950.290.800.320.29 High ratio21.874.292.186.372.261.83 Low ratio0.220.720.430.140.560.24

16. Distribution of Results for Point Sources

17. Results by Averaging Period

18. Results by Meteorological Site

20. Conclusions Average wind speeds and frequencies of light winds are similar for the 1981 and the 2005-07 meteorological data.  1981 data has slightly lower average winds and a somewhat greater frequency of light winds. Under urban dispersion conditions, ISCST3 and AERMOD yield similar peak concentrations for all source types, all averaging periods, and at all the meteorological sites.

21. Conclusions (continued) Under rural dispersion conditions, AERMOD yields significantly higher peak concentrations for point and area source types, all averaging periods, and all meteorological sites.  AERMOD-to-ISCST3 ratios are highest for point sources and for longer averaging times (i.e., 24-hour and annual concentrations).

22. AERMOD Website Go to www.aqmd.govwww.aqmd.gov Community → Air Quality → Historical Data → Meteorological Data  Both ISCST3 and AERMOD meteorological data sets are available for download and use.

23. AERMOD – Options Use regulatory default and urban option. Include terrain and building downwash For maximum annual concentrations of criteria pollutants, each calendar year must be analyzed separately. For cancer risk and chronic HI, use the entire 3- year data set in the analysis.

24. AERMOD - Implementation Rule 1303 and Rule 2005  All permit applications received on or after September 1, 2009 must use AERMOD Rule 1401  Tier 3 analyses in all permit applications received on or after September 1, 2009 must use AERMOD  Tier 4 analyses using HARP, either ISCST3 or AERMOD (use HARP On-Ramp to generate HARP files) can be used.