sarp_walsh

8/14/2019 SARP_Walsh

1/27

Acetaldehyde in the Central Valley

of California

Steven WalshSARP 2009WAS Group


2/27

Outline

- Overview

- Photochemistry

- Relationships

- Implications/conclusions- Future work

- References

- Acknowledgments


3/27

Overview

Acetaldehyde is an important resultant photochemicalspecies that is not believed to have a ground basedemission source.

Acetaldehyde and ethanol correlate well with eachother when examining all collected flight data.

Acetaldehyde to ethanol ratios do not correlate withdistinct observed acetaldehyde concentrations.

Does biomass burning affect acetaldehydeoccurence?


4/27

Conceptual model

Dairy FarmWinery/vineyard

most?

AcetaldehydeCentralValley

PhotolysisHOx

Ethanol


5/27

Acetaldehyde photochemistry

ETHANOL - OH REACTION

C2H5OH(g)

+OH(g)

.

H2O(g)

5% CH2CH2OH(g)

90% CH3CHOH(g)

.

.

5% CH3CH2O(g)

.

+O2(g)

HO2(g).

CH3CHO(g)Ethanol Acetaldehyde

Jacobson, 2002


6/27

Ethanol vs. Acetaldehyde

y = 0.1185x + 161.47

R2

= 0.6864

y = 0.1047x + 215.76

R2

= 0.6995

0

200

400

600

800

1000

1200

1400

1600

0 2000 4000 6000 8000 10000 12000

Ethanol (pptv)

Ethanol-AcetaldehydeFlight 1Ethanol-AcetaldehydeFlight 2Flight 1

Flight 2


7/27

Acetaldehyde vs. A/E

0.0000

0.2000

0.4000

0.6000

0.8000

1.0000

1.2000

1.4000

1.6000

0 200 400 600 800 1000 1200

Acetaldehyde (pptv)

Acetaldehyde

vs. A/E Flt1

Acetaldehydevs. A/E Flt2


8/27

Ethanol correlates to acetaldehyde but why isthere variability?


9/27


10/27

Flight 1 Acetaldehyde distribution


11/27

Flight 2 Acetaldehyde distribution


12/27

Can biomass burning affect theobservation of Acetaldehyde?


13/27


14/27

Automated Biomass BurningAlgorithm(ABBA GOES-8) on day July 222009-Flight 1.

Automated Biomass BurningAlgorithm(ABBA GOES-8) on day July 242009-Flight 2.


15/27

Flight 1 CH3Cl


16/27

Flight 2 CH3Cl


17/27

CH3Cl vs. Acetaldehyde

0

200

400

600

800

1000

1200

550 560 570 580 590 600 610 620 630 640

CH3Cl (pptv)

Flight 1

Flight 2


18/27

CH3Cl vs. Acetaldhyde

y = 8.0122x - 3940.5

R2

= 0.9345

y = 6.1925x - 3102.8

R2

= 0.8496

0

200

400

600

800

1000

1200

560 570 580 590 600 610 620 630 640

CH3Cl (pptv)

Flight1

Flight 2

Linear (Flight 2)

Linear (Flight1)


19/27

CH3Cl vs. Methane

R2

= 0.9094

1.88

1.9

1.92

1.94

1.96

1.98

2

2.02

2.04

560 570 580 590 600 610 620 630 640

CH3Cl (pptv)

Flight 1

Flight 2

Linear (Flight 2)


20/27

Methane vs. Acetaldehyde

R2

= 0.9589

0

200

400

600

800

1000

1200

1.88 1.9 1.92 1.94 1.96 1.98 2 2.02 2.04

Methane (ppmv)

Flight 1

Flight 2

Linear (Flight 2)


21/27

Ethanol vs. Acetaldehyde

R2

= 0.3053

300

400

500

600

700

800

900

1000

1100

2000 3000 4000 5000 6000 7000 8000

Ethanol (pptv)

Flight 1+2suspect points

Linear (Flight1+2 suspect

points)


22/27

Interpretation of suspect biomassburning samples

Distal evidence of BiomassBurning event

High ethanol source-Dairy?

Proximal tobiomass burningevent

High ethanolinfluence


23/27

Sample Methane (ppmv) Acetaldehyde (pptv) CH3Cl (pptv) A/C

Distal samples711 1.894 426 572 0.745

722 1.931 446 577 0.773

1104 1.894 575 570 1.009

Proximal samples

1116 2.019 1015 615 1.6501103 1.999 1008 621 1.623

1118 1.951 851 600 1.418

1115 1.93 765 579 1.321

710 1.909 769 609 1.263

707 1.918 729 629 1.159


24/27


25/27

Future work

- More projects on the interaction betweenbiomass burning and secondary photochemicalproducts.

- Continue to assess the impact of biomassburning against other sources of pollution.

- Continue conducting airborne missions becauseof their ability to detect secondaryphotochemical products.


26/27

References

Jacobson, M., Z. (2002). Atmospheric pollution: history, science, and regulation.Cambridge: Cambridge University Press. 109-111.

Seinfeld, J., H. and Pandis, S., N. (1998), Atmospheric chemistry and physics:From air pollution to climate change. Canada: John Wiley & Sons, Inc. 286-288.

Carter, W.P.L (1994) Development of ozone reactivity scales for volatileorganic compounds, J. Air Waste Manag. Assoc., 44, 881-899.

Steiner, A. L., Cohen, R. C., Harley, R. A., Tonse, S., Millet, D. B., Schade, G. W.,and Goldstein, A. H. (2008), VOC reactivity in central California:comparing an air quality model to ground-based measurements,Atmos. Chem. Phys., 8, 351-368.

Holzinger, R., C. Warneke, A. Hansel, A. Jordan, W. Lindinger, D. H. Scharffe, G. Schade,and P. J. Crutzen (1999), Biomass burning as a source of formaldehyde, acetaldehyde,methanol, acetone, acetonitrile, and hydrogen cyanide,Geophys. Res. Lett., 26(8), 11611164.


27/27

Acknowledgments

NASADC8 Crew

NSERC

UCIDr. Sherwood Rowland

Dr. Donald Blake

Dr. Melissa Yang

SARP WAS Group

sarp_walsh

Documents