1. 1 Near-field NO 2 Impacts due to PM Traps for Diesel Engines Tony Servin, P.E. Atmospheric Modeling and Support Section Planning and Technical Support Division May 14, 2004 Air Resources Board California Environmental Protection Agency NOxOneHr051304a.ppt

2. 2 Presentation Format Summary of Nearfield NO 2 Results Idling School Buses Details High Volume Freeway Details

3. 3 NO 2 Ambient Air Quality Standards

4. 4 NO x Emission Source Configurations Scenarios –Idling School Buses (20 buses) –High Volume Freeway (26,312 trucks/day) Consistent with… Risk Reduction Plan to Reduce Particulate Matter Emissions from Diesel-Fueled Engines and Vehicles, Air Resources Board, 2000

5. 5 Model Assumptions for NO x Exhaust Emissions Old / Screening PM Traps: No –10% NO 2 /NO x PM Traps: Yes –50% NO 2 /NO x –90% Penetration 2010 Fleet Ozone Limiting Method –Screening Level Analysis w/ High Ambient Data New / Refined PM Traps: No –10% NO 2 /NO x PM Traps: Yes –40% NO 2 /NO x –90% Penetration 2010 Fleet Ozone Limiting Method –Refined: Hourly Ambient Data to Estimate NO 2 from NO x

6. 6 1-Hour NO 2 Results

7. 7 Annual NO 2 Results

8. 8 Idling School Buses Details

9. 9 Idling School Buses 20 buses queued 5 at a time Five minute idle time Idle at 8 am and 2 pm NOx emissions (EMFAC2002 V2.2) –Idle: 80.7 g/hr –Running 17.9 g/mile at 5 mph for 60 m Hourly Ambient Data and Met. Data –2002 Los Angeles North Main ISCST3 Model with Rural Dispersion

10. 10 Idling School Buses 1-Hour Results

11. 11 Idling School Buses - 1-Hour Results Overall Top 3 Maximum

12. 12 Idling School Buses - 1-Hour Results 3 Highest Above Ambient Impacts + Ambient

13. 13 Idling School Buses Annual Screening Results

14. 14 High Volume Freeway Details

15. 15 High Volume Freeway 26,312 trucks per day average –99th percentile for 2000 in California 189,936 vehicle per day total weekday NO x emissions (EMFAC2002 V2.2) –vehicle type, vehicle speed, ambient temperature, and relative humidity –2010 fleet emissions with 90% penetration Hourly Ambient Data and Met. Data –2002 North Long Beach CAL3QHCR

16. 16 Receptors at 20 meters from Edge

17. 17 Weekday Diurnal Traffic Volume 189,936 vehicles per day (Caltrans 2000)

18. 18 Weekend Diurnal Traffic Volume 117,262 vehicles per day (Caltrans 2000)

19. 19 Long Beach Freeway Vehicle Speed (Caltrans)

20. 20 Average North Long Beach Temperature and Relative Humidity

21. 21 Weekday Diurnal NOx Emissions

22. 22 Weekend Diurnal NOx Emissions

23. 23 High Volume Freeway 1-Hour Results Table 3 – Refined 1-Hour NO 2 Impacts for High Volume Freeway Particulate ControlMaximum (b) Note W/O Traps (10% NO 2 )150 ppb(a) W/Traps (40% NO 2 )180 ppb(a) Notes: (a) One Hour California State Standard for NO 2 is 250 ppb (b) Ambient NO 2 is included as background

24. 24 High Vol. Freeway - 1-Hour Results Overall Top 3 Maximum

25. 25 High Vol. Freeway - 1-Hour Results 3 Highest Above Ambient Impacts + Ambient

26. 26 High Volume Freeway Annual Screening Results Table 4 – Screening Above Ambient Annual Average NO 2 Impacts for High Volume Freeway Particulate ControlMaximum (b) Note W/O Traps (10% NO 2 ) 18 ppb(a) W/Traps (50% NO 2 ) 18 ppb(a) Notes: (a) Annual Average Federal Standard is 53 ppb NO 2 (b) Receptor located 20 meters from edge of freeway

27. 27 Summary of New Refined Analysis

28. 28 Summary – 1 Hr NO 2 Table 5 – Summary of 1-Hour NO 2 Impacts due to Particulate Traps (a), (b) Scenario PM Traps: No (10% NO 2 /NO x ) PM Traps: Yes (40% NO 2 /NO x ) Idling School Buses (c) 120 ppb170 ppb Freeway (d) 150 ppb180 ppb (a) These results include ambient hourly NO 2 as background. (b) The California State standard for 1-Hr NO 2 is 250 ppb. (c) Idling School Buses include 20 buses idling for 5 minutes with hourly O 3. (d) High Volume Freeway is for 26,312 trucks per day with hourly O 3.