1. Guidance on Attainment Tests for O3 / PM / Regional Haze
Ellen Baldridge & Joe Tikvart
Air Quality Modeling Group / EPA
2nd Models-3 Workshop
Research Triangle Park, NC 27711
October 21, 2002

2. Status of Modeling Guidance
Guidance for Estimating Attainment of
8-hour Ozone NAAQS (Draft)
Guidance for Demonstrating Attainment of Air Quality Goals for PM2.5 and Regional Haze (Draft)
Modeling Guidance -- DRAFT8HR
Modeling Guidance -- DRAFT-PM

3. Status of Modeling Guidance (continued)
Drafts extensively reviewed by
Regional Offices
State representatives
Stakeholder groups
Ellen Baldridge – O3
Brian Timin – PM2.5 & regional haze

4. What is in the Modeling Guidance?
How to use modeling and other analyses
– modeled attainment demonstration through relative reduction factors
– screening test
– weight of evidence
How to setup and apply models

5. Modeled Attainment Demonstration – Relative Reduction Factors –
Use models to predict relative changes in concentrations
– determine site specific observed design values
– model current pollutant concentrations
– model future pollutant concentrations
– calculate RRFs as ratios of future to current
– estimate future concentrations as a product
of observed design values and RRFs
For PM2.5, sum across components
(RRF each for SO4, NO3, OC, EC, IP, CM)

6. Screening Test
Concentrations are predicted where there are no nearby monitors
Predicted concentrations are greater than those in vicinity of monitors
Maximum areawide design value is multiplied by RRFs for non-monitor locations to estimate design value

7. Weight of Evidence Supplement to attainment test
Core plus additional analyses
Other air quality estimates
(e.g., grid-cell hours >NAAQS)
Analysis of air quality & emission trends
Receptor oriented models
Results of all analyses are reviewed and weighed

8. Modeling Systems for Ozone
Urban Airshed Models
(UAM, MAQSIP, CALGRID, etc.)
CAMx
(source apportionment capability)
Models3/CMAQ
Model performance/accuracy is well established

9. Modeling Systems for PM2.5
Models3/CMAQ – proof-of-concept applications as basis for support and guidance
REMSAD – policy analysis applications & national rules
Other regional models
– PM-CAMx, URM, UAM-AERO, SAQM

10. Other PM Modeling Approaches
Source Apportionment
– PM-CAMx & CMAQ
“Hot spot” analyses
– ISC, AERMOD, CALPUFF
Receptor models
– CMB, UNMIX, PMF

11. Upcoming Modeling Activities
Continue model performance evaluation
Explore sulfate, nitrate, and organic issues
SMOKE w/ BEIS3, Mobile-6, improved NH3, fires, primary PM emissions
Vertical layer sensitivity modeling
Nitrate oriented sensitivities