1. 1-hour NO2 Modeling Issues
WESTAR Spring 2011 Business Meeting

2. The Issues for New Mexico
Many NOx sources in the state
Refined methods needed to demonstrate compliance
Statutory deadlines for permit issuance
Refined model methods not tested for accuracy with refined methods, such as PVMRM
USEPA guidance suggests myriad of analyses not possible to accomplish within deadlines

3. AERMOD Workgroup Convened by USEPA
Over 50 participating state and local representatives
Currently constructing generic scenarios
State will model and demonstrate results in June
USEPA to present conclusions Fall 2011

4. NMED/AQB Modeling Guidelines
Rely on monitor data for 1-hour NO2 in short-term
No modeling required for 1-hour NO2 pending outcome of AERMOD workgroup
Propose and justify use of MRM
Use background monitor concentrations rather than modeled background

5. What is MRM? Monitored Ratio Method
Compares NOx concentrations to NO2/NOx ratios to determine upper bound conversion
In-stack ratio determines lower bound conversion
Easily applied as a post-processor to modeling results