California Regional PM 10 /PM 2.5 Air Quality Study (CRPAQS) Technical Update

1. California Regional PM10/PM2.5 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 PM2.5 levels during CRPAQS monitoring • Present findings from data analysis projects • Identify some of the future challenges

3. Central California is a PM2.5 non-attainment area

4. The California Regional PM10/PM2.5 Air Quality Study (CRPAQS) • Period: Dec. 2, 1999 – Feb. 3, 2001 • Frequency: Every 6th day (Daily 24-hr mass measurement at Fresno and Bakersfield) • Location: 5 PM2.5 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 FSF SNFH BTI ANG BAC

5. Time Integrated Samplers RAAS-100 single-channel PM2.5 FRM sampler (Andersen Instruments, Smyrna, GA) RAAS-400 PM2.5 speciation sampler(Andersen Instruments, Smyrna, GA) Dual-channel sequential filter sampler(Desert Research Institute, Reno, NV) MiniVol filter sampler(Airmetrics, Springfield, OR)

6. Annual average and maximum PM2.5 concentrations(6th day sampling) BTI SNFH 70 FSF 9 ANG BAK Max Longitude Annual Average (2/1/2000 – 1/31/2001)

7. PM2.5 seasonal distribution Spring Winter Summer Fall Longitude Longitude

8. Annual PM2.5 chemical composition

9. Summer and winter nitrate (NO3-) Summer • Low NO3- found in summer (<3.5 µg/m3) (Note: different scales) • Nitrate highest near urban areas. Winter • High NO3- found in winter. • Nitrate high throughout SJV.

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

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

14. Regional- and Urban-Scale Influences BethelDatesIslandFoothillsFresnoAngiolaBakersfield IOP 1Dec. 15-18mixcarbonmixnitratemix IOP 2Dec. 26-28carbon carbon carbonnitratemix IOP 3Jan. 4-7nitrate nitratemixnitratenitrate IOP 4Jan. 31-Feb. 1nitratemixcarbonnitratecarbon

15. Composition varies throughout dayHypothesis of nitrate mixing from aloft

16. Angiola tower nitrate confirms hypothesis

17. Substantial amounts of excess NOx, even at non-urban sites Is HNO3 NOx or VOC limited? HNO3 data were not available at Bethel Island and Bakersfield

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/dlogDp (number cm-3)

20. Elevated O3 and PM2.5 rarely occur togetherFresno, hourly data Spring Summer Fall Winter

21. CRPAQS results confirm focus on reducing emissions from many sources and pollutants • What 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 • 2005 • Finalize data analysis projects • Begin weight of evidence/reconciliation analysis. • Complete model development and evaluation • 2006 • 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, GA • More than 50 technical publications. More in progress • Development and testing of new continuous monitoring instruments • Refined conceptual models of air quality evolution in valleys and foggy conditions • Refined conceptual model of ultrafine particle formation with low sulfur conditions

25. The target is changingEPA Staff Paper Current Standards Indicator Ave. Time Conc. Statistical Form PM10 24 hr 150 not to exceed more than 1/yr Annual 50 arithmetic mean PM2.5 24 hr 65 3 yr average of 98th percentile Annual 15 3 yr average of arithmetic mean Proposed Range of Standards PM10-2.5 24 hr 65 – 75 at 98th percentile or: 75 – 85 at 99th percentile Annual 30 at 98th percentile or: 35 at 99th percentile PM2.5 24 hr 25 – 35 at 99th percentile Annual 15 or: 24 hr 35 – 40 (at 98th percentile?) Annual 12 – 14

26. Remaining questions • Is nitrate limited by ammonia levels in sub-regions during late summer and fall? • Is nitric acid formation limited by VOCs or NOx? • Will population and vehicle use growth offset emissions reductions per unit? • Will unidentified high emitters dominate overall emissions?