Improving PM 2.5 forecasting ability of Hi-Res in southeastern United States

1. Improving PM2.5 forecasting ability of Hi-Res in southeastern United States Yongtao Hu, Jaemeen Baek, M. Talat Odman and Armistead G. Russell School of Civil & Environmental Engineering Georgia Institute of Technology Presented at the 7th Annual CMAS Conference, October 7th, 2008 Georgia Institute of Technology

2. Outline • The Hi-Res air quality forecasting system. • 2007 O3 and PM2.5 performance. • Performance investigation using PM2.5 components measurements. • New Secondary Organic Aerosol (SOA) module. • Experiment with new SOA module and results. Georgia Institute of Technology

3. Hi-Res: forecasting ozone and PM2.5 at a 4-km resolution in metro Atlanta area Snapshots from Hi-Res homepage: http://forecast.ce.gatech.edu • Three grids: • 36-km (72x72) • 12-km (72x72) • 4-km (99x78) • 34 vertical layers used in WRF • 13 layers in CMAQ Georgia Institute of Technology

4. SLAMS sites • 7 PM2.5 • 10 O3 Speciated PM2.5 observed at 7 sites • 2 Search • 4 ASACA • 1 STN Ambient Monitoring Sites for Performance Evaluation Georgia Institute of Technology

5. 2007 O3 Performance: Hi-Res vs. EPD’s 4-km Forecast EPD Ensemble Forecast Hits False Alarms Missed Exceedences Correct Nonevents Georgia Institute of Technology

6. Forecastedvs. Observed O3 Georgia Institute of Technology

7. Ozone Season 2006 vs. 2007 Georgia Institute of Technology

8. 2007 PM2.5 Performance: Hi-Res vs. EPD’s Our 4-km Forecast EPD Ensemble Forecast Georgia Institute of Technology

9. Forecastedvs. Observed PM2.5 Georgia Institute of Technology

10. Summer 2006 vs. 2007 Georgia Institute of Technology

11. Forecastedvs. Observed PM2.5 Georgia Institute of Technology

12. Forecastedvs. Observed PM2.5 Components Ammonium Sulfate Organic Carbon Nitrate Elemental Carbon Georgia Institute of Technology

13. Organic Carbon G-F wild fire Over-prediction Under-estimation Georgia Institute of Technology

14. Aging process: +OH,+O3 Aerosol +OH,+O3 LSVOC HSVOC New SOA module* developed at Georgia Tech SOA species in CMAQ: Included processes: • SOA partitioned from Anthropogenic VOCs’ oxidations (8 SVOCs) • From monoterpenes (2 SVOCs) • From isoprene (2 SVOCs added) • From sesquiterpenes (1 SVOC added, gas phase oxidation reactions added for α-caryphyllene, β-humulene and other sesquiterpenes) • Aging of all semi-volatile organic carbons (SVOCs)added • AORGAJ and AORGAI • AORGBJ and AORGBI • AORGBISJ and AORGBISI • AORGBSQJ and AORGBSQI • AORGAGJ and AORGAGI *Baek et al. 2008, manuscipt in preparation. Georgia Institute of Technology

15. Simulated Secondary Organic Contributions From Monoterpene From Isoprene From Sesquiterpene From Antropogenic VOCs Compare to Primary From Aged SVOCs Georgia Institute of Technology

16. PM2.5 performance improves Georgia Institute of Technology

17. before and after OC performance Georgia Institute of Technology

18. Summary • 2007 Ozone forecasts are good. • Overall bias is +8.5% and error is 19% • PM2.5 forecasts are not very accurate. • May-September bias is -37% and error is 44% • FL-GA wildfires of 2007 impacts • Performance is much better in Fall and Spring • Wintertime PM2.5 was overestimated, Summertime PM2.5 was underestimated • PM2.5 components • Inorganic components are generally OK • organic components are worse • SOA formation is possibly underestimated • New SOA module “improves” the summer PM2.5 forecasts • Better emissions estimations for organic PM is critical Georgia Institute of Technology

19. Acknowledgements Georgia EPD has funded the forecasts. Dr. Michael Chang, EAS of Georgia Tech. Our ASACA team: Sivaraman Balachandran, Emily Katherine Lantrip, Laura Anne Parry, ... for ASACA data. Southern Company for SEARCH data. Georgia Institute of Technology

20. Performance Metrics Forecast Observation Georgia Institute of Technology

21. Georgia Institute of Technology