Further Development and Application of the CMAQ Ozone and Particle Precursor Tagging Methodologies (OPTM & PPTM)

7th Annual CMAS ConferenceChapel Hill, NC

6-8 October 2008

Presented by Sharon Douglas ICF International, San Rafael, CA

Co-Authors:

Tom Myers Yihua Wei Jay Haney Tom Braverman,

ICF

EPA OAQPS

Presentation Outline

Overview of CMAQ/OPTM & PPTM source attribution methods

Application of CMAQ/OPTM & CMAQ/PPTM to support ozone & PM2.5 designations (example for Milwaukee)

Application of CMAQ/PPTM to characterize CAAA-related reductions in PM2.5 for cost/benefit analysis

Next steps

OPTM & PPTM: General Concepts

Emissions (or IC/BC) species are tagged in the input files and continuously tracked throughout the simulation

Tags can be applied to source regions, source categories, individual sources, and/or IC/BCs

Tagged species have the same properties and are subjected to the same processes (e.g., advection, chemical transformation, deposition) as the actual species

OPTM & PPTM: General Concepts

OPTM species include ozone, NOx & VOC

PPTM species include PM-related S, N, SOA, POC, EC & other inorganic particulates*

Base simulation results not affected by tagging

OPTM & PPTM quantify the contribution of tagged sources to simulated species concentrations & deposition

*PPTM has also been implemented for mercury

Implementation of OPTM for CMAQ (Overview(1))

Total emissions of both NOx and VOC from the desired sources or source categories are tagged (e.g., NOx_t1, NOx_t2, VOC_t1, VOC_t2)

Oxidant tracers (OXN_t1, OXV_t1, OXN_t2, OXV_t2) correspond to the oxidant produced from NOx & VOC for each tagged category

Implementation of OPTM for CMAQ (Overview(2))

Advection/Diffusion: Use standard CMAQ algorithms

Gas Phase Chemistry: Chemistry step called as usual Changes in NOx, VOC & oxidant (ΔVOC, ΔNOX

& ΔOX) are calculated and apportioned to tags

Deposition: Calculated for the tags based on fractional

change in total NOx, VOC & oxidant due to deposition

Implementation of PPTM for CMAQ (Overview)

Within CMAQ, tagging is accomplished by adding duplicate species (e.g., ANO3_t1, ANO3_t2)

More than 50 (gas & aerosol phase) species per tag required to track total PM2.5 (e.g., for nitrogen: ANH4I, ANH4J, ANO3I, ANO3J, NO, NO2, NO3, N2O5 …)

Key considerations/assumptions: Linear processes simulated directly Potentially non-linear processes calculated for total

species and apportioned to tags

PPTM can also be used to estimate contributions to N and other forms of deposition

Application of CMAQ/OPTM & PPTM for the Milwaukee Area

Objective: To identify the source regions that potentially contribute to high ozone and high PM2.5 concentrations in the Milwaukee, WI area

Specs: Regional-scale modeling domain 2002 base year; limited simulation periods (1

month for ozone; 4 months for PM2.5) 13 tagged source regions (county level)

Application of CMAQ/OPTM & PPTM for the Milwaukee Area:

Domain

12-km resolution

Application of CMAQ/OPTM & PPTM for the Milwaukee Area:

Tags

T1: Milwaukee Co., WIT2: Washington Co., WIT3: Ozaukee Co., WIT4: Waukesha Co., WIT5: Racine Co., WIT6: Sheboygan & Fond du Lac Co., WIT7: Dodge, Jefferson & Walworth Co., WIT8: Kenosha Co., WIT9: Cook Co., ILT10: Lake, McHenry, Kane, Dupage Co.,ILT11: Will Co., IL & Lake & Porter Co., INT12: Remainder of 12-km gridT13: IC/BCs

CMAQ/OPTM Results for the Milwaukee Area: NOx

Average Contribution to Maximum 8-Hour Ozone

Tag 1: Milwaukee Co. Tag 9: Cook Co. Tag 10: 4 Other IL Co.

CMAQ/OPTM Results for the Milwaukee Area: VOC

Average Contribution to Maximum 8-Hour Ozone

Tag 1: Milwaukee Co. Tag 9: Cook Co. Tag 10: 4 Other IL Co.

CMAQ/OPTM Results for a Monitoring Site: NOx & VOC

CMAQ/OPTM Contributions to 8-Hr Ozone for Milwaukee: NOx & VOC

0

20

40

60

80

100

T1 T2 T3 T4 T5 T6 T7 T8 T9 T10 T11 T12 T13 Total

pp

b

NOx VOC

Milwaukee Bayside

Milwaukee Co. 12-km grid

IC/BCs

Average Contribution to Maximum 8-Hour Ozone

Summary CMAQ/OPTM Results for All Monitoring Sites: NOx &

VOCSummary of CMAQ/OPTM NOx Contributions to 8-Hr Ozone for Milwaukee: High Ozone Days

0

10

20

30

40

50

KPP MCHC MDNR MUWM MBYS OGFT OHBP RAPC WSLG WCLV

pp

b

Milwaukee Co. Other Tagged WI Counties Tagged IL & IN Counties Remainder of 12-km Grid IC/BCsSummary of CMAQ/OPTM VOC Contributions to 8-Hr Ozone for Milwaukee: High Ozone Days

0

10

20

30

40

50

KPP MCHC MDNR MUWM MBYS OGFT OHBP RAPC WSLG WCLV

pp

b

Milwaukee Co. Other Tagged WI Counties Tagged IL & IN Counties Remainder of 12-km Grid IC/BCs

CMAQ/PPTM Source Region & Species Contributions to Avg PM2.5 for Milwaukee

0

2

4

6

8

T1 T2 T3 T4 T5 T6 T7 T8 T9 T10 T11 T12 T13

ug

/m3

SO4 NO3 NH4 POA PEC Other Primary PM2.5

CMAQ/PPTM Results for a Monitoring Site

Milwaukee Virginia Fire Station

Milwaukee Co.

12-km grid IC/BCs

CMAQ/PPTM Source Region & Species Contributions to Avg PM2.5 for Milwaukee

0

2

4

6

8

T1 T2 T3 T4 T5 T6 T7 T8 T9 T10 T11 T12 T13

ug

/m3

SO4 NO3 NH4 POA PEC Other Primary PM2.5

CMAQ/PPTM Results for a Monitoring Site

Waukesha

Milwaukee Co.

12-km grid IC/BCs

Waukesha Co.

Summary CMAQ/PPTM Results for All Monitoring Sites

Summary of CMAQ/PPTM Source Region Contributions to Avg PM2.5 for Milwaukee

0

2

4

6

8

DNR FDH CHC FAA VFS OZK WKS

ug

/m3

Milwaukee Co. Other Tagged WI Counties Tagged IL & IN Counties Remainder of 12-km Grid IC/BCs

Summary for Milwaukee

OPTM & PPTM can be used to quantify the contribution of emissions (by species) from

specified source regions to CMAQ-derived concentrations

the potential for sources/source regions to contribute to nonattainment in a given area

Contributions vary by location and are different for the different species (NOx, VOC and PM species)

Ozone & PM2.5 nonattainment issues in the Milwaukee area are the combined result of local emissions as well as intra- & inter-state transport

§812 Cost/Benefit Analysis: PM2.5 Modeling Component

CMAQ-Ready 36-km Emission Inventories

(US Domain)1990

2000 without CAAA2000 with CAAA

2010 without CAAA2010 with CAAA

2020 without CAAA2020 with CAAA

2002 Meteorological Inputs

Geophysical & IC/BC Inputs

CMAQ Model (Version 4.6)

Annual PM2.5, Visibility & Deposition(US Domain)

19902000 without CAAA

2000 with CAAA2010 without CAAA

2010 with CAAA2020 without CAAA

2020 with CAAA

Health and Ecological Assessments

Annual Simulation Period

Application of CMAQ/PPTM to Support the §812 Cost/Benefit

Analysis

Objectives: Quality assurance To quantify and compare the source category

contributions to PM2.5 both with and without the Clean Air Act Amendments (CAAA)

Specs: National-scale modeling domain Annual simulation period; two scenarios (2010

without CAAA and 2010 with CAAA) 7 tagged source categories

Application of CMAQ/PPTM for the §812 Modeling Analysis:

Domains

36-km resolution for PM2.5

CONUS

EUS

WUS

Application of CMAQ/PPTM for the §812 Modeling Analysis:

Tags

T1: EGU sources (U.S.) T2: Non-EGU point sources (U.S.) T3: On-road mobile sources (U.S.) T4: Non-road mobile sources (U.S.) T5: Area (non-point, non-mobile) sources

(U.S.) T6: Initial and boundary conditions (IC/BCs)

T7: All other sources (natural emissions, offshore sources, and non-U.S. sources)

CMAQ/PPTM Results: Contribution from EGU Sources (Tag 1)

2010 without CAAA 2010 with CAAA

Annual Average PM2.5

CMAQ/PPTM Results: Contribution from Non-EGU Point Sources (Tag

2)

2010 without CAAA 2010 with CAAA

Annual Average PM2.5

CMAQ/PPTM Results: Contribution from On-Road Sources (Tag 3)

2010 without CAAA 2010 with CAAA

Annual Average PM2.5

0

10

20

30

40

50

EGU Non-EGU On-roadmobile

Non-roadmobile

Area IC/BCs Other Total

ug

/m3

NoCAAA CAAA

CMAQ/PPTM Results for a Monitoring Site

Philadelphia

Annual Average PM2.5

Summary of PPTM Results for the §812 Modeling Analysis

PPTM used as a probing tool to attribute the overall reductions in PM2.5 (due to the CAAA measures) to specific source categories

Total simulated PM2.5 concentration is lower under the CAAA scenario, primarily due to reductions in area- & point-source (EGU & non-EGU) emissions (relative importance varies by region and by location)

Health benefits can be similarly attributed to source categories, sources, or specific measures

Next Steps

Incorporate OPTM & PPTM (for ozone and PM2.5) into CMAQv4.7

Incorporate PPTM (for mercury and 10 additional toxic pollutants) into CMAQv4.7

Distribute OPTM & PPTM codes through CMAS