Title: California Regional PM10PM2'5 Air Quality Study CRPAQS Technical Update
1California 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
2Objectives
- Review PM2.5 levels during CRPAQS monitoring
- Present findings from data analysis projects
- Identify some of the future challenges
3Central California is a PM2.5 non-attainment area
4The 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
5Time 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)
6Annual 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)
7PM2.5 seasonal distribution
Spring
Winter
Fall
Summer
Longitude
Longitude
8Annual PM2.5 chemical composition
9Summer 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.
10Summer 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.
11Summer 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
12Wood smoke marker (levoglucosan) highest at urban
sites
Annual OC Distribution
13Diurnal Variation During IOP 3 (Jan. 4-7,
2001)BlueOrganics (1.4)BlackEC
(IMPROVE)RedAmm. NitrateYellowAmm.
SulfateBrownSoil
14Regional- 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
15Composition varies throughout dayHypothesis of
nitrate mixing from aloft
16Angiola tower nitrate confirms hypothesis
17Substantial 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
18Fog increases deposition and PM removal
19Ultrafine 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)
20Elevated O3 and PM2.5 rarely occur
togetherFresno, hourly data
Spring
Summer
Winter
Fall
21CRPAQS 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
22CRPAQS 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
23CRPAQS 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
24CRPAQS 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
25The 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
26Remaining 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?