1. Department of Environmental Quality
Trajectory Analyses of Class I areas in the Central and Western U.S. on 20% Worst Days Between 2011 and 2016
Department of Environmental Quality

2. Purpose & Methodology
Performed back trajectories on active Class I sites in the western portion of the VISTAS domain.
Purpose: Determine if these sites need to be analyzed further in work to complete Regional Haze SIPs among the VISTAS states.
Methodology: 72-hour back trajectories ending at 10, 100, 300, 500, 750, 1000, 1500 and 2000 meters AGL.
Using NAM 12km data.
Looked at 20% worst days from 2011 to 2016.
Data from IMPROVE website.

3. Texas

4. Oklahoma

5. Kansas

6. Nebraska

7. South Dakota

8. North Dakota

9. Minnesota

10. Montana

11. Wyoming

12. Colorado

13. New Mexico

14. Conclusions
Sites in the following states do not need to be modeled or have Q/d analysis done:
Colorado
Wyoming
Montana
North Dakota
South Dakota
Nebraska
Sites in the following states may need to be modeled or have Q/d analysis done:
Texas
Oklahoma
Kansas
Minnesota
New Mexico