California Regional PM10PM2'5 Air Quality Study CRPAQS Technical Update

1
California Regional PM10/PM2.5 Air Quality Study
(CRPAQS) Technical Update

• John G. Watson (johnw_at_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
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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. 31Feb. 3, 2001

FSF
SNFH
BTI
ANG
BAC
5
Time Integrated Samplers
Dual-channel sequential filter sampler(Desert
Research Institute, Reno, NV)
RAAS-400 PM2.5 speciation sampler(Andersen
Instruments, Smyrna, GA)
RAAS-100 single-channel PM2.5 FRM sampler
(Andersen Instruments, Smyrna, GA)
MiniVol filter sampler(Airmetrics, Springfield,
OR)
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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
Fall
Summer
Longitude
Longitude
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Annual PM2.5 chemical composition
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Summer and winter nitrate (NO3-)
Summer

• Low NO3- found in summer (lt3.5 µg/m3) (Note
  different scales)
• Nitrate highest near urban areas.

Winter

• High NO3- found in winter.
• Nitrate high throughout SJV.

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Summer and winter organic carbon (OC)

• Uniform OC in the southeastern valley. Highest OC
  near a dairy.

Summer
Fresno Feedlot
Winter

• Elevated OC at urban centers, especially near the
  Fresno Supersite. OC in rural areas was lower in
  winter than in summer.

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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)BlueOrganics (1.4)BlackEC
(IMPROVE)RedAmm. NitrateYellowAmm.
SulfateBrownSoil
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Regional- and Urban-Scale Influences

• BethelDates Island Foothills Fresno Angiola Bake
  rsfield
• IOP 1Dec. 15-18 mix carbon mix nitrate mix
• IOP 2Dec. 26-28 carbon carbon carbon nitrate mix
• IOP 3Jan. 4-7 nitrate nitrate mix nitrate nitrate
  
• IOP 4Jan. 31-Feb. 1 nitrate mix carbon nitrate ca
  rbon

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Composition varies throughout dayHypothesis of
nitrate mixing from aloft
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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)
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Elevated O3 and PM2.5 rarely occur
togetherFresno, hourly data
Spring
Summer
Winter
Fall
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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

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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

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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
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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?