Assessment of the Relative Reduction Factor for an

Ozone Attainment Demonstration in Houston,

TX

August 17, 2009Alejandro Valencia

1

How is model predicted O3 sensitive to day type emission variability and morning Planetary Boundary Layer rise?

Hypothesis

2

Outline Introduction

Modeling Datasets

Results

Conclusions

Future work

How is model predicted O3 sensitive to day type emission variability and Planetary Boundary Layer rise?

3

Ozone - A Secondary Criteria Pollutant

Health effect

Environmental Problems

Factors in O3 Production: Emissions

NOxVOC

Meteorology Wind ProfileRise of Planetary Boundary Layer

4

Houston is Non-attainment Area

Ship Channel

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The O3 Standard

National Ambient Air Quality Standard (NAAQS) for O3 8-hour standard: 0.08 ppm

State Implantation Plan (SIP) Current SIP (8-hour standard)

Attainment Test based on Relative Model predictions

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How to develop Attainment Test for the SIP

EPA Guidance: 8-hr Ozone Attainment Test

Monitor by Monitor Test Based on Observations

Maximum 8-hr Averages Based on Air Quality Models (AQMs)

Base case -- used in simulation performance not in Attainment Test

Base line case -- ‘typical’ emission inventory Future case -- ‘controlled’ emission inventory

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The 8-hr Ozone Attainment Test

DVF = RRF x DVB

Future design value If it is below the standard

the monitor is in compliance of NAAQS

Baseline design value based on observations

Relative Reduction Factor based on model predictions

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DVF = RRF x DVB Year 2003 2004 2005 2006 2007

1st 0.104 0.103 .101 .100 .102

2nd 0.103 0.101 .098 .099 .094

3rd 0.092 0.101 .092 .095 .088

4th 0.091 0.095 .088 .090 .082

5th 0.088 0.094 .087 .090 .079

Avg. of DVs

0.0913 0.0900 0.0866

2005 DVB 0.0893

Ozo

ne D

ata

for

Hig

hest

Dai

ly 8

-hr

max

(pp

m)

9

DVF = RRF x DVB

Average of predicted Future case 8-hr daily max “near”

monitorAverage of predicted Base line case 8-hr daily max “near” monitor

RRF =

O3Future

O3Base line

=Day 1F+Day 2F …. Day NF

N RRF days

Day 1B+Day 2B …. Day NB

N RRF days

=RRFM =

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An RRF Example

0.891 represent a reduction of 11% of DVB

Lower RRF values indicate larger relative decreases in future predicted ozone concentrations

When calculating an RRF remember : EPA recommends a threshold concentration of 85

ppb for days used in RRF calculations, but allows concentrations as low as 70 ppb.

EPA recommends using at least 10 days in calculating RRFs, but allows as few as 5 days

RRFM = = 0.891

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Day Type Emissions

How is model predicted O3 sensitive to day type emission variability?

NOx

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Changing “The Box” changes Emission Concentrations

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Different SimulatedPlanetary Boundary Layer Rises

How is model predicted O3 sensitive to Planetary Boundary Layer rise? 14

Outline Introduction

Modeling Datasets

Results

Conclusions

Future work

How is model predicted O3 sensitive to day type emission variability and Planetary Boundary Layer rise?

15

Modeling Standard Attainment Dataset

The Texas Commission of Environmental Quality (TCEQ) developed Attainment Test for the SIP 8-hr O3 Attainment Test for 25 Surface Monitors

Calculating 25 DVB, RRFs, and DVF

4 monitors failed attainment test 18 AQMs Simulation Episodes using CAMx

2005 Base case 120 modeling days from 2005 and 2006 episodes

2005 Base line case 120 modeling days from 2005 and 2006 episodes

2018 Future case 120 modeling Days projected to 2018

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Across the Board Emissions Controls Applied with Growth

600 TPD 364 TPD

992 TPD 1011 TPD

Base Line Case 2005 Future Case 2018

NOx

VOC

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Outline Introduction

Modeling Datasets

Results

Conclusions

Future work

How is model predicted O3 sensitive to day type emission variability and Planetary Boundary Layer rise?

18

Results

Weekday Weekend Analysis Results

Meteorological Analysis Results

Process Analysis Results

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Results

Weekday Weekend ResultsMeteorological Analysis Results

Process Analysis Results

Do different type of day emissions affect Houston’s predicted O3 ?

Day Type Emissions Variability

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Central Houston

1,250 km221

Different Concentrations for Weekdays and Weekends

HRVOC = Highly Reactive VOCs,

Weekday Weekend

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Spread of Weekdays to Weekends in the Attainment Dataset

63

10

46

17

23

Weekday Weekend O3Base

lineP

redi

cted

8-h

r m

ax O

3

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Weekday Weekend O3Future

Pre

dict

ed 8

-hr

max

O3

25

Weekday Weekend RRF

0.03 – 0.08

< 0.02

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Weekday Weekend DVF

DVB influence > RRF

2-6 ppb

< 2 ppbO3

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Weekday Weekend Summary and Conclusions

NOx emissions on the weekends constitute a reduction on average of 13% Eastern Houston monitors affected by industrial emissions

have higher weekend O3 Western Houston monitors affected by mobile emissions

have lower weekend O3

Model response to changes in day type emission is sensitive to location

O3 concentrations can vary by as much as 35 ppb and RRFs can vary by up to 0.08 between weekdays and weekends.

Arbitrary averaging different day type Emission introduces a margin of error that may vary attainment

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ResultsWeekday-Weekend Results

Meteorological Analysis ResultsProcess Analysis Results

How does the model simulate the PBL ?

The Simulated Planetary boundary or Model Mixing Volume (MMV) is produced by the AQM by adjusting the vertical mixing (kv) between layers in the Eularian grid structure.

SimulatedPlanetary Boundary Layer Height

How is O3 sensitive to MMV ? 29

MMV with focus on Central Houston

1,250 km230

2 Distinct MMV RisesSlow Riser = MMV change less than 700

m/h

between 6 to 11 LST

Fast Riser = MMV change more than 700 m/h

between 6 to 11 LST

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MMV of Slow Riser & Fast Riser “Slow Riser” August 1, 2005

9 am

1- Hour O3 144 ppb

“Fast Riser” August 6, 2005 1- Hour O3 124 ppb

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Fast Riser higher than Slow Riser

7 am

“Fast Riser” August 6, 2005 9 LST“Slow Riser” August 1, 2005 9 LST

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Spread of Slow Risers to Fast Risers in the Attainment Dataset

63

10

41

22

34

Slow Riser Fast Riser O3Base line

Pre

dict

ed 8

-hr

max

O3

35

Slow Riser Fast Riser O3Future

Pre

dict

ed 8

-hr

max

O3

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Slow Riser Fast Riser RRF

Fast Riser respond better to 2018 controls

0.062x the difference of day type

0.07

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Slow Riser Fast Riser DVFDVf per Monitor, Type of Riser

DVB > Riser influence > Type of day

3-6 ppb

2-4 ppbO3

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Meteorological Analysis Summary and Conclusions

O3 concentrations can vary by 35 ppb and RRFs as much as 0.07 between Slow Risers and Fast Risers.

Model response to changes in MMV Rise is sensitive to location

Fast Risers are more responsive to 2018 Controls than slow risers Reponses to Controls varies with MMV Rise Type

Rise in MMVs can influence DVFs enough to bring them into attainment or out of attainment

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ResultsEmission Inventory Results

Meteorological Analysis Results

Process Analysis Results

Too much NOx = NOx-inhibitedToo much VOC = NOx-limited

Why is it important how O3 is produced in the studied phenomena ?

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Process Analysis: Central Houston

1,250 km241

4 new-modeled days

Type of Day

MMV Rise

Weekday

Slow

Weekday

Fast

Weekend

Slow

Weekend

Fast

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2 Emission Inventories

Weekday

Weekend

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2 Meteorological Days

Slow Riser

Fast Riser

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Physical Processes : NOx

Slow Riser Fast Riser

06/21/05 Weekday

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Physical Processes : VOC

Slow Riser Fast Riser

06/21/05 Weekday

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Physical Processes : O3

Slow Riser Fast Riser

06/21/05 Weekday

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A Very Simple Intro to O3 Chemistry

OH. + VOCHO2

RO2 RO. OH.

NO NO2

O2

O3

O2 .

.

HNO3

NOx-limited H2O2

NO2 HO2

NOx-inhibited

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Fast Riser NOx-limited Earlier, Longer

Weekday

OH + NO2 HNO3HO2 + HO2 H2O2 + O2

NOx-limited NOx-inhibited

- P(H2O2) : P(HNO3)

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Process Analysis Summary and Conclusions

2 distinct rising MMV patterns show the same behavior in both emission types with different magnitudes. Slow Riser Fast Riser

Entrainment of VOCs that bring in new VOCs 5x more Dilution of NOx and VOCs Steeper O3 production rate mainly due to entrainment NOx-limited much earlier in day than Slow Riser

Restricts O3 formation to NOx availability

Lower & Earlier Peak O3

Same set of EI show distinct O3 producing regimes Affect the type of controls needed to reduce O3

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Outline Introduction

Modeling Datasets

Results

Conclusions

Future work

How is model predicted O3 sensitive to day type emission variability and Planetary Boundary Layer rise?

51

ConclusionsRRF

Modeled data are “averaged” over weekday and weekend emissions and over recurring meteorological phenomena. Averaging of these phenomena results in an artificial

response in many cases is less responsive than actual conditions

Houston Complex Environment with different response to

across the board controls Several ways to produce ozone require different

controls

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Outline Introduction

Modeling Datasets

Results

Conclusions

Future work

How is model predicted O3 sensitive to day type emission variability and Planetary Boundary Layer rise?

53

Future Work Develop DVB as a function of weekend and weekday.

Calculate only weekend and only weekday DVF

Compare Slow Riser and Fast Riser phenomena with Observed data.

Use Process Analysis to compare eastern clusters of monitors with western monitors

Design optimum control strategies that consider variability due to geographic location, MMV rise, and day type emissions of Houston

Expand criteria for days selected when using the RRF averaging metric

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Acknowledgements Dr. Vizuete

MAQ Lab

CHAQ Lab

Dr. Jeffries

Dr. Arnold

Barron Henderson

This project was funded by the HARC under Project H97.

Image SourcesLiz Christophhttp://www.flickr.com/photos/mendt/2512431584/http://www.flickr.com/photos/ncabral/2271356021/http://www.flickr.com/photos/mzmo/2831224265/http://www.flickr.com/photos/oneeighteen/2583724580/http://www.flickr.com/photos/kt/20140715/http://www.flickr.com/photos/60058591@N00/577718015/in/set-72157615763158669/http://www.flickr.com/photos/60058591@N00/577718005/http://www.stateoftheair.org/2008/most-polluted/http://www.flickr.com/photos/telwink/2147903485/sizes/l/http://www.flickr.com/photos/eschipul/269752158/sizes/l/http://www.flickr.com/photos/billjacobus1/122489774/sizes/l/http://www.flickr.com/photos/telwink/2252360890/sizes/l/http://www.flickr.com/photos/arielp/14701974/sizes/l/http://www.flickr.com/photos/oneeighteen/1318669651/sizes/o/http://www.flickr.com/photos/fusionpanda/258048488/sizes/l/http://www.flickr.com/photos/travishouston/3303021742/

Sourceshttp://www.tceq.state.tx.us/http://www.tceq.state.tx.us/implementation/air/airmod/committee/pmtc_set.htmlEvan CouzoBarron HendersonDick Karp. Initial 2018 hgb modeling results.

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Questions

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Appendix : Process Analysis Results

H2O2 and HNO3 Production

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Appendix : Process Analysis Results

H2O2 and HNO3 Production

- - - - - - - - - - - - - - -

OH + NO2 HNO3

________________

HO2 + HO2 H2O2 + O2 58

Weekend

Appendix : Process Analysis Results

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