1. California Regional PM 10 /PM 2.5 Air Quality Study (CRPAQS) Technical Update John G. Watson (johnw@dri.edu) Philip M. Roth Karen L. Magliano Central California Air Quality Studies Policy Committee February 25, 2005

2. Objectives Review PM 2.5 levels during CRPAQS monitoringReview PM 2.5 levels during CRPAQS monitoring Present findings from data analysis projectsPresent findings from data analysis projects Identify some of the future challengesIdentify some of the future challenges

3. Central California is a PM 2.5 non-attainment area

4. The California Regional PM 10 /PM 2.5 Air Quality Study (CRPAQS) Period: Dec. 2, 1999 – Feb. 3, 2001 Frequency: Every 6 th day (Daily 24-hr mass measurement at Fresno and Bakersfield) Location: 5 PM 2.5 anchor sites and 32 satellite sites Anchor sites: Bethel Island (BTI), Sierra Nevada Foothill (SNFH), Fresno (FSF), Angiola (ANG), Bakersfield (BAC). Winter IOP periods: –Dec. 15-18, 2000 –Dec. 26-28, 2000 –Jan. 4-7, 2001 –Jan. 31–Feb. 3, 2001 BTI ANG BAC SNFH FSF

5. Time Integrated Samplers Dual-channel sequential filter sampler (Desert Research Institute, Reno, NV) RAAS-400 PM 2.5 speciation sampler (Andersen Instruments, Smyrna, GA) RAAS-100 single-channel PM 2.5 FRM sampler (Andersen Instruments, Smyrna, GA) MiniVol filter sampler (Airmetrics, Springfield, OR)

6. Longitude Annual average and maximum PM 2.5 concentrations (6 th day sampling) (2/1/2000 – 1/31/2001) BTI SNFH BAK 70 9 FSF Max Annual Average ANG

7. PM 2.5 seasonal distribution Winter FallSummer Spring Longitude

8. Annual PM 2.5 chemical composition

9. Summer and winter nitrate (NO 3 - ) Low NO 3 - found in summer (<3.5 µg/m 3 ) (Note: different scales) Nitrate highest near urban areas. Summer Winter High NO 3 - found in winter. Nitrate high throughout SJV.

10. Summer and winter organic carbon (OC) Uniform OC in the southeastern valley. Highest OC near a dairy. Elevated OC at urban centers, especially near the Fresno Supersite. OC in rural areas was lower in winter than in summer. Summer Winter Fresno Feedlot

11. Summer and winter elemental carbon (EC) Higher EC around urban centers. Elevated EC found near the Fresno Supersite and Bakersfield. Rural sites show limited summer-winter contrast. Summer Winter EC

12. Wood smoke marker (levoglucosan) highest at urban sites Annual OC Distribution

13. Diurnal Variation During IOP 3 (Jan. 4-7, 2001) Blue=Organics (1.4) Black=EC (IMPROVE) Red=Amm. Nitrate Yellow=Amm. Sulfate Brown=Soil

14. Regional- and Urban-Scale Influences Bethel DatesIslandFoothillsFresnoAngiola Bakersfield IOP 1 Dec. 15-18 mixcarbonmixnitratemix IOP 2 Dec. 26-28 carboncarboncarbonnitratemix IOP 3 Jan. 4-7 nitratenitratemixnitratenitrate IOP 4 Jan. 31-Feb. 1 nitratemixcarbonnitratecarbon

15. Composition varies throughout day Hypothesis of nitrate mixing from aloft

16. Angiola tower nitrate confirms hypothesis

17. HNO 3 data were not available at Bethel Island and Bakersfield Substantial amounts of excess NO x, even at non-urban sites Is HNO 3 NO x or VOC limited?

18. Fog increases deposition and PM removal

19. Ultrafine particles are directly emitted and form from atmospheric reactions (Fresno, CA, 3/29/2003) Vehicle Exhaust, Residential Heating and Cooking Photochemical Nucleation Vehicle Exhaust Particle Diameter (nm) dN/dlogD p (number cm -3 )

20. Elevated O 3 and PM 2.5 rarely occur together Fresno, hourly data Spring WinterFall Summer

21. CRPAQS results confirm focus on reducing emissions from many sources and pollutants What has been doneWhat has been done –Oil heaters switched from crude oil to natural gas, added SCR –Extensive controls and offsets on new industrial sources –Residential and prescribed burning rules –Improved on-road pollution controls and inspection and maintenance –Unpaved surface stabilization –Agricultural conservation management plans –Dairy permitting program

22. CRPAQS results confirm focus on reducing emissions from many sources and pollutants –Oil heaters switched from crude oil to natural gas, added SCR –Extensive controls and offsets on new industrial sources –Residential and prescribed burning rules –Improved on-road pollution controls and inspection and maintenance –Unpaved surface stabilization –Agricultural conservation management plans –Lower sulfur diesel fuels –Tighter emission standards for on-road and off- road diesel engines

23. CRPAQS activities 20052005 –Finalize data analysis projects –Begin weight of evidence/reconciliation analysis. –Complete model development and evaluation 20062006 –Complete weight of evidence/reconciliation analysis –Complete emissions projections and control strategy modeling

24. CRPAQS scientific contributions More than 20 technical presentations at February supersite meeting, Atlanta, GAMore than 20 technical presentations at February supersite meeting, Atlanta, GA More than 50 technical publications. More in progressMore than 50 technical publications. More in progress Development and testing of new continuous monitoring instrumentsDevelopment and testing of new continuous monitoring instruments Refined conceptual models of air quality evolution in valleys and foggy conditionsRefined conceptual models of air quality evolution in valleys and foggy conditions Refined conceptual model of ultrafine particle formation with low sulfur conditionsRefined conceptual model of ultrafine particle formation with low sulfur conditions

25. Current Standards Indicator Ave. Time Conc.Statistical Form PM 10 24 hr 150not to exceed more than 1/yr Annual 50arithmetic mean PM 2.5 24 hr 653 yr average of 98 th percentile Annual 153 yr average of arithmetic mean Proposed Range of Standards PM 10-2.5 24 hr 65 – 75 at 98 th percentile or: 75 – 85 at 99 th percentile Annual 30 at 98 th percentile or: 35 at 99 th percentile PM 2.5 24 hr 25 – 35 at 99 th percentile Annual 15 or: 24 hr35 – 40 ( at 98 th percentile?) Annual 12 – 14 The target is changing EPA Staff Paper

26. Remaining questions Is nitrate limited by ammonia levels in sub- regions during late summer and fall?Is nitrate limited by ammonia levels in sub- regions during late summer and fall? Is nitric acid formation limited by VOCs or NO x ?Is nitric acid formation limited by VOCs or NO x ? Will population and vehicle use growth offset emissions reductions per unit?Will population and vehicle use growth offset emissions reductions per unit? Will unidentified high emitters dominate overall emissions?Will unidentified high emitters dominate overall emissions?