Analysis of Houston's 2000 CAMx SIP Model: Radical sensitivity

Rapid Science Synthesis Group Austin, TX

10/12/2006

William Vizuete

Harvey Jeffries

vizuete@unc.edu

http://ftpozone.sph.unc.edu/

Work Supported By• Eight Hour Ozone Coalition• HARC

– H60 “Regional Transport Modeling for East Texas”– Jay Olaguer, Project Officer.

• TCEQ – Thanks Jim Smith for supplying CAMx ready

outputs for SIP Modeling• AG

– Also thank Dennis McNally and Tom TescheAlpine Geophysics for sharing simulation results.

• UNC Modeling Air Quality (MAQ) Lab – Marianthi-Anna Kioumourtzoglou, Barron

Henderson, Leiran Biton

RSSG Question K

How can observation and modeling approaches be used for determining (i) the sensitivities of high ozone in the HGB non-attainment area to the precursor VOC and NOx emissions, and (ii) the spatial/temporal variation of these sensitivities?

Outline• Base Model

– The 2000 Houston Attainment Model– CAMx– TCEQ “base1b”

• VOC Sensitivity– CO: Radical propagation– Xylene: Internal radical source– Formaldehyde: Direct radical source

• Process Analysis Results

The 2000 Houston Attainment Model

• Comprehensive Air Quality model with Extensions (CAMx)

• TCEQ “base1b”• NOx (esp NO2), CO, HRVOCs bias

high at surface, esp. East.• Ozone peak bias low.

VOC Sensitivity :CO and Xylene+Toluene

• Two CO sensitivity runs– 4xCO: 4 times the gridded CO emissions– 0.25xCO: 1/4 times the gridded CO emissions– Full length run (08.22-09.06.2006)– Domain wide imputation (36km, 12km, and 4km)

• Xylene and Toluene sensitivity run– 2xXYL_TOL: 2 times the Xylene and Toluene

gridded emissions– Full length run– Domain wide imputation

VOC Sensitivity : Formaldehyde

• Two Formaldehyde sensitivity runs– Flares (FL_FORM)

• We assumed that HCHO emitted was equal to 1% of total VOC flow rate.

– Mobile sources (CO_FORM)• Recent data (SWRI, 2005*) on Heavy Duty

Diesel show that HCHO is 23% of VOC and ethene is 18% of THC. HCHO was 5% of CO.

• We added HCHO at 4% of low level CO.

*Reference: Diesel Exhaust Standard-Phase II: CRC Project No. AVFL-10b SwRI Poject No. 03.10410 Fanick, Robert. 2005

Peak Ozone at Houston Monitors:Obs, Base, and FL_FORM

•Process Analysis•CAMx/CMAQ quantifies the chemical and physical processes that lead to ozone formation for each grid cell•Process Analysis is a post processor suite of programs that extracts, aggregates and calculates several chemical parameters.

•Chemical parameters•Total OH Balance•Total VOC Reacted•New NO•Total NO Reacted•Total NO2 Available•O3 Source Balance•O3 Balance•New O3 per new NO and VOC reacted

What is Process Analysis?

Map of what?CHOU(13x6)WHOU(7x4)EHOU(6x4)

VOC Sensitivity: CHOU Ozone Impact

999994938487Ozone Peak

129122119120100105Ozone Produced

CO_FORMFL_FORM2xXYL_TOL4xCO0.25xCOBase

Values representative entire CHOU area

Total OH Balance

19.3 18.7 20.3 20.3 21.4 21.2

14.4 14.4 14.4 16 16.8 18.474.1 68.6 90.9 81.8 85.2 89.8

3.23.1

3.6 3.23.3

3.3

0

20

40

60

80

100

120

140

Base

0.25

xCO

4xCO

2xXYL_

TOL

FL_F

ORMCO

_FORM

PA Focus Regions

#:OH cyclesrecreated OHnew OH, org new OH, inorg

CHOU8/25

Total VOC+CO Reacted

80 74 98 89 93 98

449 334785 452 461 467

1.8

1.9

1.7

1.8 1.8 1.8

0

100

200

300

400

500

600

700

800

900

Base

0.25

xCO

4xCO

2xXYL_

TOL

FL_F

ORMCO

_FORM

PA Focus Regions

Total VOC Reacted

66 66 6574 77 8077 76 7780 88 94

2.2 2.1 2.52.2

2.12.2

0

20

40

60

80

100

120

140

160

180

Base

0.25

xCO

4xCO

2xXYL_

TOL

FL_F

ORMCO_F

ORM

PA Focus Regions

CHOU8/25

#:(NO to NO2)/VOCVOC availableVOC reacted

OH + VOCs, CO, CH4, NO2

NO2 23%

CO 14%

FORM 15%

ALD2 12%

MGLY 0%

OPEN 0%

CH4 4%

PAR 7%

MEOH 1%

ETOH 0%

ETH 6%

OLE 9%

TOL 1%

XYL 1%

CRES 1%

ISOP ISPD

3%

CHOU8/258hr

OH + VOCs, CO, CH4, NO2

NO2 22%

CO 14%

FORM 18%

ALD2 12%

MGLY 0%

OPEN 0%

CH4 4%

PAR 8%

MEOH 1%

ETOH 0%

ETH 6%

OLE 8%

TOL 0%

XYL 1%

CRES 1%

ISOP

ISPD 2%

CHOU8/25

FORMeqFLVOC

OH Reacted with VOC…

Total OH Reacted: 107 ppbTotal VOC Reacted: 80 ppb

Total OH Reacted: 129 ppbTotal VOC Reacted: 93 ppb

NO reacted

2.0 1.9

2.3 2.2 2.3 2.4

020406080

100120140160180

Base

0.25

xCO

4xCO

2xXYL_

TOL

FL_F

ORMCO

_FORM

PA Focus Regions

# NO Cyclerecreated NO Total new NO

CHOU8/25

Total NO2 Balance

-200-180-160-140-120-100

-80-60-40-20

020

Base

0.25

xCO

4xCO

2xXYL_

TOL

FL_F

ORMCO

_FORM

PA Focus Regions

NO2 Photolyzed NO2 entrain/dil NO2 chem. loss NO2 deposition NO2 trans NO2 Final

CHOU8/25

O3 Source Balance

0

50

100

150

200

Base

0.25

xCO

4xCO

2xXYL_

TOL

FL_F

ORMCO_F

ORM

PA Focus Regions

new O3O3, V transport O3, initial

CHOU8/25

O3 Balance

-140

-120

-100

-80

-60

-40

-20

0

20

40

60

Base

0.25

xCO

4xCO

2xXYL_

TOL

FL_F

ORMCO_F

ORM

PA Focus Regions

O3, photolyzedO3, reactedO3, entr/dilO3, H transport O3, final O3, deposition

CHOU8/25

Total OH Balance

19.9 19.2 21.3 21.3 21.6 22.5

14.2 14.2 14.2 16.1 14.1 19.672.3 65.2 95.4 82.2 76.8

94

3.12.9

3.7

3.1

3.2

3.2

0

20

40

60

80

100

120

140

160

Base

0.25

xCO

4xCO

2xXYL_

TOL

FL_F

ORMCO

_FORM

PA Focus Regions

WHOU8/25

#:OH cyclesrecreated OHnew OH, org new OH, inorg

Total OH Balance

17.8 17.3 18.2 18.3 20.6 18.8

15.5 15.5 15.6 1722 18.4

76 72.5 84.4 8299.4

85.6

3.3 3.23.5

3.3

3.33.3

0

20

40

60

80

100

120

140

160

Base

0.25

xCO

4xCO

2xXYL_

TOL

FL_F

ORMCO

_FORM

PA Focus Regions

EHOU8/25

•Radical Sensitivity•VOC/NOx Ratio •Observational evidence

•Monitor•Aircraft

•How can we assess the correct radical source strength at surfacesites?

–Should we be making Kleinman-like measurements (canister VOCs, aldehydes, NOy and N-species, and radiation measurements) at several monitor sites and apply his constrained steady state model to estimate P(O3) and thus infer radical source strengths from measurements that can be compared with model.

RSSG Question K