` 1 Source Attribution of Mobile Source Air Toxics Eric M. Fujita, David E. Campbell, William P....

1 `

Source Attribution of Mobile Source Air Toxics

Eric M. Fujita, David E. Campbell, William P. Arnott and Barbara Zielinska

Division of Atmospheric SciencesDesert Research InstituteUniversity and Community College System of

NevadaReno, Nevada

2006 CRC MSAT WorkshopPhoenix, AZ

October 23-25, 2006

2 `

Source Apportionment of SI and CI Exhaust to Ambient MSAT Concentrations

• Receptor Modeling – Chemical Mass Balance

• Correlations of MSAT with CO, NMHC, NOx or BC/EC.

• Multivariate regression of CO, NOx, PM2.5 or BC with LDV and HDV traffic volumes

• Spatial variations ambient MSAT relative to known variations in LDV and HDV traffic volumes.

• Temporal variations in ambient pollutant concentrations (e.g., day of week).

3 `

Acknowledgments• Weekend Ozone Study

– Sponsor: DOE’s Office of FreedomCAR and Vehicle Technologies, Dr. James Eberhardt and National Renewable Energy Laboratory, Dr. Douglas Lawson

– Additional Support: South Coast Air Quality Management District

• Gasoline/Diesel PM Split Study

– Sponsor: DOE’s Office of FreedomCAR and Vehicle Technologies, Dr. James Eberhardt and National Renewable Energy Laboratory, Dr. Douglas Lawson

– Additional Support: U.S. Environmental Protection Agency. California Bureau of Automotive Repair, South Coast Air Quality Management District, Ralph’s Supermarket Distribution Center

• Assessing Exposure to Air Toxics in Microenvironments Dominated by Mobile Sources – Sponsor: Health Effects Institute, Dr. Debra Kaden

– Additional Support: South Coast Air Quality Management District.

4 `

0

1

2

3

4

5

Sat, 9/30 Sun, 10/1 Mon, 10/2 Tue, 10/3 Wed, 10/4 Thu, 10/5 Fri, 10/6 Sat, 10/7 Sun, 10/8

0

0.5

1

1.5

2

2.5

3

Black Carbon (ug/m3)

CO (ppm)

Weekday Variations in CO and Black Carbon at Azusa, 9/30/00 to 10/8/00Weekend Ozone Study

5 `

0

100

200

300

400

500


0.0

0.4

0.8

1.2

1.6

2.0

NMHC

CO (ppm)

Weekday Variations in CO and at Azusa, 9/30/00 to 10/8/00Weekend Ozone Study

6 `

Black Carbon and NOx at Azusa, 9/30/00 to 10/8/00

0

1

2

3

4

5


0

20

40

60

80

100BC (ug/m3)

NOx (ppb)

Weekday Variations in NOx and Black Carbon at Azusa, 9/30/00 to 10/8/00Weekend Ozone Study

7 `

1-minute average Black Carbon

(Photoacoustic)

Sunday

Weekday

DOE Gas/Diesel PM Split Study

8 `

Carbon Monoxide

Health Effects Institute Project RFA03-1

405 110

60

710 605

91

9 `

Black Carbon (Photoacoustic)


405 110

60

710 605

91

10 `

Sampling Locations During the Phase II Field MeasurementsWeekend Ozone Study

AzusaPAMS

Pico RiveraPAMS

ComptonLoop

CovinaLoop

PomonaLoop

Industry HillsConference Center

DodgerStadium

UplandPAMS

Los AngelesNorth Main

South Coast Air Basin

TruckStop

110 FreewayNo Trucks

Ambient VOC at PAMS

Regional/Background Sites

Source-Dominated Samples

AzusaPAMS

Pico RiveraPAMS

ComptonLoop

CovinaLoop

PomonaLoop

Industry HillsConference Center

DodgerStadium

UplandPAMS

Los AngelesNorth Main

South Coast Air Basin

TruckStop

110 FreewayNo Trucks

Ambient VOC at PAMS

Regional/Background Sites

Source-Dominated Samples

DSCVIH

PO

CO

DOE Weekend Ozone Study

11 `

Source Apportionment of BenzeneWeekend Ozone Study

Benzene

0.0

2.0

4.0

6.0

8.0

IH1 IH2 DS1 DS2 CV1 CV2 CO1 CO2 PO1

Gasoline Exhaust Diesel Exhaust Gasoline Vapor Coatings Consumer Products

0%

20%

40%

60%

80%

100%


Regional Sites Freeways


12 `

Source Apportionment of TolueneWeekend Ozone Study

Toluene

0

4

8

12

16

20



0%

20%

40%

60%

80%

100%




13 `

Source Apportionment of StyreneWeekend Ozone Study

0.0

0.5

1.0

1.5

2.0



0%

20%

40%

60%

80%

100%




14 `

Source Apportionment of 1,3-ButadieneWeekend Ozone Study

0.0

0.5

1.0

1.5

2.0



0%

20%

40%

60%

80%

100%




15 `

Source Apportionment of MTBEWeekend Ozone Study

0

4

8

12

16

20

24



0%

20%

40%

60%

80%

100%




16 `

Source Apportionment of CO, NO, PM2.5, and BC by Multivariate Analysis Using Traffic Counts

• Where:

– Pe = estimated on-road pollutant concentration

– VD = heavy-duty trucks per hour (a metric of diesel engine emissions)

– VG = light and medium duty vehicles per hour (a metric of gasoline engine emissions)

• Source of uncertainty

– Traffic volumes are annual hourly averages.

– On-road measurements can be influenced by surrounding traffic.

[ ] GDe bVaVP +=


17 `

2005 Hourly Traffic Volumes

0

5,000

10,000

15,000

20,000

25,000

Hourly Traffic Count

0%

25%

50%

75%

100%

405N

405N/110N

60W to605

60W from

605405S

110S/405S60E to 60560E from

605 710N60E 605S 91W 710N

60E 605S 91W 710N60E 605S 91W

7-8 am 5-6 pm 7-8 am 11-noon 5-6 pm

Cars Trucks

Commute Routes Truck Routes


18 `

Contribution of SI and CI Exhaust to On-road CO, NO, PM2.5 and BC Concentrations*

CO (ppm)

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

I405N, I110NI110S, I405S

I405N I405S

SR60W toI605

SR60W from

I605 SR60E toI605

SR60E from

I605I710N SR60E I605S

SR91W

% from diesel % from gasoline

< TRUCK ROUTES >

NO (ppb)

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

I405N, I110NI110S, I405S

I405N I405S

SR60W toI605

SR60W from

I605 SR60E toI605

SR60E from

I605I710N SR60E I605S

SR91W


< TRUCK ROUTES >

PM2.5 (µg/m3)

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

I405N, I110NI110S, I405S

I405N I405S

SR60W toI605

SR60W from

I605 SR60E toI605

SR60E from

I605I710N SR60E I605S

SR91W


< TRUCK ROUTES >

BC (ug/m3)

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

I405N, I110NI110S, I405S

I405N I405S

SR60W toI605

SR60W from

I605 SR60E toI605

SR60E from

I605I710N SR60E I605S

SR91W


< TRUCK ROUTES >

Health Effects Institute Project RFA03-1 * Estimated from correlations of on-road measurements and traffic volumes.

19 `

Correlations with CO at Los Angeles-N. Main 1990-95 and 1996-02 Benzene

y = 1.05x + 0.66

R 2 = 0.62

y = 0.94x + 0.04

R 2 = 0.91

0

2

4

6

8

10

0 2 4 6 8

CO (ppm)

Benzene (ppbv)

Toluene

y = 2.49x + 0.56

R 2 = 0.62

y = 2.20x + 0.22

R 2 = 0.78

0

5

10

15

20

25

0 2 4 6 8

CO (ppm)

Toluene (ppbv)

1990 to 1995

1996 to 2002

n-Butane

y = 0.30x + 0.01

R 2 = 0.71

y = 0.29x + 0.02

R2 = 0.90

0

1

2

3

4

0 2 4 6 8

CO (ppm)

Butane (ppbv)

PAH (ng/m3) PAH (ng/m3)

Formaldehyde

y = 1.36x + 0.45

R 2 = 0.41

y = 1.56x + 2.06

R2 = 0.27

0

3

6

9

12

15

0 2 4 6 8

CO (ppm)

Formaldehyde (ppbv)

Data from ARB Air Toxic Monitoring

20 `

Total Carbon (IMPROVE)

0.0

0.2

0.4

0.6

0.8

1.0

Fractional SCE

Diesel Gasoline Residual

Total Carbon (STN)

0.0

0.2

0.4

0.6

0.8

1.0

Azusa SunAzusa MonAzusa TueAzusa WedAzusa ThuAzusa FriAzusa SatLANM SunLANM MonLANM TueLANM WedLANM Thu

LANM FriLANM Sat

San Dimas Mon

Venice Sat

Rose Bowl Sat

I-405 Sun

Fractional SCE

Total Carbon Source Contributions

DOE Gas/Diesel PM Split Study

21 `

Variations in Source Contribution Estimates (Percent of Total) Azusa and Los Angles Weekday Ambient Samples

Compression-Ignition Spark-Ignition

IMPROVE STN STN no PAH IMPROVE STN STN no PAH

TC

Mean 40.9 30.8 31.3 6.6 9.4 11.4

Std Dev 3.7 3.0 2.7 1.3 3.3 3.5

Std Err 1.2 1.0 0.9 0.4 1.0 1.1

OC

Mean 22.1 15.8 16.1 7.4 10.4 12.2

Std Dev 2.6 2.0 1.9 1.7 3.6 3.7

Std Err 0.8 0.6 0.6 0.5 1.1 1.2

EC

Mean 90.3 93.3 65.9 4.5 5.2 7.2

Std Dev 3.3 3.4 5.9 1.0 2.1 2.0

Std Err 1.0 1.1 1.9 0.3 0.7 0.6

22 `

Summary

• Ambient levels of volatile organic MSATs in the SoCAB were mainly associated with SI vehicle exhaust. However, SI and CI contributions were comparable for styrene.

• Evaporative contributions to volatile organic MSAT in the SoCAB were minor.

• CI and SI apportionments varied with location and time.

– CI vehicles were the dominant mobile source of EC and TC at Azusa and LANM.

– More equal apportionment at other locations that are more regionally representative.

– SI vehicles were the dominant mobile source of OC and EC in locations and times with minimal truck traffic.

– EC is a reasonable surrogate of PM emissions from CI vehicles in the SoCAB.

• Short-term on-road exposures (few minute or less) can be substantially higher and depend on proximity of high gasoline emitters and diesel trucks.

• Over half of the organic carbon during summer in the SoCAB could not be apportioned to directly-emitted PM emissions from motor vehicles.

23 `

References

Fujita, E.M., W.R. Stockwell, D.E. Campbell, R.E. Keislar and D.R. Lawson (2003). Evolution of the Magnitude and Spatial Extent of the Weekend Ozone Effect in California’s South Coast Air Basin from 1981 to 2000. J. Air & Waste Manage. Assoc. 53:802-815

Fujita, E.M., D.E. Campbell, B. Zielinska, J.C. Sagebiel, J.L. Bowen, W. Goliff, W.R. Stockwell, and D.R. Lawson (2003). Diurnal and Weekday Variations in Source Contributions of Ozone Precursors in California’s South Coast Air Basin. J. Air & Waste Manage. Assoc. 53: 844-863.

Fujita, E.M. and D.E. Campbell (2006). Spatial and Temporal Variations in Exposure to Air Toxics in the South Coast Air Basin. Draft final report submitted by Desert Research Institute to the National Renewable Energy Laboratory, Golden, CO, August 31, 2006.

Fujita, E.M., D.E. Campbell, B. Zielinska, W.P. Arnott and J.C. Chow (2006). Exposure to Air Toxics in Mobile Source Dominated Microenvironments. Draft report submitted by Desert Research Institute to the Health Effects Institute, Boston, MA, July 27, 2006.

Fujita, E.M., B. Zielinska, W.P. Arnott, D.E. Campbell, L. Rinehart, J.C. Sagebiel and J.C. Chow (2006). Gasoline/Diesel PM Split Study: Source and Ambient Sampling, Chemical Analysis, and Apportionment Phase. Final report submitted to the U.S. Department of Energy National Renewable Energy Laboratory, Golden, CO, January 19, 2006. Data are available at: http://www.nrel.gov/vehiclesandfuels/nfti/feat_split_study.html

Fujita, E.M., B. Zielinska, D.E. Campbell, W.P. Arnott, J. Sagebiel, L. Reinhart, J.C. Chow, N. P.A. Gabele, W. Crews, R. Snow, N. Clark, S. Wayne and D.R. Lawson. Variations in speciated emissions from spark-ignition and compression ignition motor vehicles in the California's South Coast Air Basin. In Press.

Fujita, E. M., D. E. Campbell, W. P. Arnott, B. Zielinska. Evaluations Of Source Apportionment Methods for Determining Contributions Of Gasoline and Diesel Exhaust to Ambient Carbonaceous Aerosols. Submitted.

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