Western States Air Quality Study Background Air Quality Modeling

University of North Carolina (UNC-IE)ENVIRON International Corporation (ENVIRON)

May 13, 2015

Western States Air Quality Study

Intermountain West Data Warehouse

3SAQS/WSAQS Modeling

• Create a standardized regional modeling platform for NEPA and other Western U.S. air quality studies

• Cooperators at the NPS, USFS, BLM, EPA Region 8, States of CO, UT, WY

• Populate a centralized modeling data repository

• USBG Context– Project is focused on rural

ozone– Quantify regional background

air quality– Understand influence of

transport on Western U.S. air quality

– Source apportionment

3SAQS/WSAQS Modeling

2012 2013 2014

OCT 2012Pilot Project

Start

NOV-DEC 2012CO, UT, WY

2008 EI Analysis and Evaluation

FEB 20143SAQS Monitoring

Network Report

OCT 2013WRF 2011

Sensitivities

AUG 2014CAMx 2008b,

WRF 2011, 2011 Oil & Gas EI,

2011a Emissions

JUL 2014Final 2008 Emissions

OCT 2014CAMx 2011a

MPE

SEP 2014SMOKE 2011a

JUN 2012Emissions VOC

Reactivity Analysis

FEB-MAY 20122008 EI

Modeling

MAR-JUN 20142011 EI

Modeling

NOV 2014-APR 2015

CAMx 2011 Sensitivities

2015

AUG 2012CAMx 2008a

JAN 2013EI Improvement Meetings With

CO, UT, WY

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WSAQS Project Timeline

2015

DEC 2014- APR 2015Base11a MPEv2

JAN-MAR CMAQ Base11a

JAN-APR WRF Winter

Modeling Configuration

MAR-JUN2011b Emissions

Development

AUG 2011b CAMx

MPE

JUN-JUL2011b CAMx

Modeling

Early SEP 2015Technical Comm

Meeting

SEP 2015Release CAMx

2011bNOV

Prelim 2014

Platform Release

April 29-30Tech Comm Call

MAYBase2011a

Platform Release; MOVES and Winter O3

CAMx Complete

APR Phase II O&G

EI Release

MAY-AUG2014a WRF and SMOKE

JAN 21Governing

Board Meeting

FEB 25, 2015Technical Comm

Meeting

JUL 2015Technical

Comm Call

WSAQS U.S. Background Simulation

• Objectives– Use a regional Chemistry-Transport model to estimate U.S. background (USBG) air quality in the West

• Design– CAMxv6.10

• Annual 2011 36/12/4-km

– All U.S. anthropogenic emissions removed– Downscale NCAR MOZART-GEOS5 GCM to CONUS36-km BCs

with CB6r2 chemistry

Urban (AQS) Rural (CASTNET)

WSAQS USBG SimulationCAMx 12-km Monthly Mean Daily Max 8-hr O3 (MDA8)

Seasonal Averages at CASTNET Monitors April 2011: USBG – Base

April 2011: Daily Max Surface O3WSAQS USBG SimulationCAMx 12-km Monthly Mean MDA8

CO CASTNET Sites

WSAQS USBG SimulationCAMx 12-km Monthly Mean MDA8

Domain CASTNET AQS

AZ 45.7 43.9

CA 42.7 38.7

CO 47.2 45.6

ID N/A 42.0

MT N/A 40.9

NM N/A 46.2

NV 46.1 43.6

OR N/A 36.3

UT 44.5 43.3

WA 38.6 38.5

WY 45.2 42.7

• Results– Annual average domain-wide

background MDA8 at • CASTNET = 43.7 ppb• AQS = 42.0 ppb

– Annual maximum domain-wide background MDA8 at• CASTNET = 79.9 ppb (April)• AQS = 83.5 ppb (May)

Annual Average MDA8 CAMx 12-km USBG (ppb)

• Unrealistically high background contribution to total PM2.5 at IMPROVE sites.

WSAQS USBG SimulationCAMx 12-km Monthly Mean Total PM2.5

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3SAQS Base 2011a MPEPM2.5 PerformanceBoundary Conditions • MOZART BCs found to be contributing

too much dust to the CAMx simulation• Replacing MOZART with GEOS-Chem

BCs drastically improves Total PM2.5 model performance

• 4-km domain IMPROVE spring NMB:• MZBC = 155%• GCBC = -8.5%

• 3SAQS BC Sensitivity Wiki*

*http://vibe.cira.colostate.edu/wiki/wiki/1043/bc-sensitivity-modeling-results

Boundary Condition Sensitivity Tests

• Objectives– Investigate regional model performance issues related to boundary

conditions (BCs) downscaled from global chemistry models (GCMs)– Identify systematic problems in the available GCM BCs– Produce recommendations for how to use GCM BCs for regional

modeling in the West– Find a best-performing BC dataset for simulation 2011b

• Design– Downscale MOZART, GEOS-Chem, and AM3 to CONUS36-km BCs

with CB6r2 chemistry– Winter/summer simulations with CAMx to evaluate the influence

of the different BCs on model performance

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WSAQS BC SensitivitiesCAMx 12-km January 2011 Hourly O3

CASTNET

AQS

• Rural (CASTNET)– AM3 is high– MZ and GC are

comparable during the day

– GC low at night• Urban (AQS)– AM3 is high– GC is the lowest of

the three and best match to obs

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WSAQS BC SensitivitiesCAMx 12-km July 2011 Hourly O3

CASTNET

AQS

• Rural (CASTNET) and Urban (AQS)– No significant

difference between any of the GCMs

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WSAQS BC SensitivitiesCAMx 12-km IMPROVE Daily Total PM2.5

January

July

• January– CAMx overestimates

total PM2.5 with all GCMs

– MZ is incrementally worse than others

• July– Overestimates with

MZ– Underestimates with

GC and AM3

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• Cap MZBC dust concentrations (FCRS and CCRS) and zero-out sea salt– Besides dust, MZBC produces lower biases for inorganic

PM2.5 and O3 than the other GCM BCs

• CAMx TOPCON simulation• Perform annual 2011 36/12 km BC sensitivity test– Annual MPE to make sure no new issues related to BC– Adopt BCs for 2011b platform by end of May/early Jun

WSAQS BC Sensitivities2011 Western Modeling Platform: Next Steps

16

• Need for a detailed evaluation of GCM results in the context of downscaling to Western regional modeling applications– Conduct this evaluation before significant efforts to

evaluate regional modeling– Regional models should be part of the GCM

evaluation suite• What role can the GCM community play in

advising regional modelers on how to use GCM data in downscaled applications?

WSAQS BC Sensitivities2014 Western Modeling Platform: Looking Forward