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

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) http://www.epa.gov/ttn/scram Modeling Guidance -- DRAFT8HR Modeling Guidance -- DRAFT-PM

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

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

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)

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

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

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

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

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

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