1. Nitrogen Deposition at Rocky Mountain National Park: the RoMANS Study Mike Barna Bill Malm Bret Schichtel Kristi Gebhart Air Resources Division National Park Service U.S. Department of the Interior Ozone and NOx in the West Meeting November 11, 2009 Santa Fe, NM

2. RoMANS Nitrogen deposition at Rocky Mountain NP has exceeded a critical load of 1.5 kg/ha/yr RoMANS: Rocky Mountain Atmospheric Nitrogen and Sulfur Study Field measurement campaigns conducted in spring and summer of 2006 Which source regions / source types are contributing to N deposition at RMNP?

3. RoMANS participants FEDERAL GOVERNMENT AGENCIES NPS NOAA USGS USFS EPA STATE OF COLORADO Colorado State University Colorado Department of Public Health and Environment CONTRACTORS Air Resource Specialists University of California Desert Research Institute Research Triangle Institute

4. RoMANS objectives Characterize the atmospheric concentrations of sulfur and nitrogen species in gaseous, particulate and aqueous phases (precipitation and clouds) along the east and west sides of the Continental Divide (Organic Nitrogen?) –GAS: NH 3, R-NH 2, NO X (NO+NO 2 ), NO Y (HNO 3, PAN, etc) –PARTICLE: NH 4, NO 3, ORGANICS (reduced and oxidized)? – WET (rain, snow, and clouds): NH 4, NO 3, ORGANICS (reduced and oxidized)? Identify the relative contributions to atmospheric sulfur and nitrogen species in RMNP from within and outside of the state of Colorado. Identify the relative contributions to atmospheric sulfur and nitrogen species in RMNP from emission sources along the Colorado Front Range versus other areas within Colorado. Identify the relative contributions to atmospheric sulfur and nitrogen species from mobile sources, agricultural activities, large and small point sources within the state of Colorado. Characterize the atmospheric concentrations of sulfur and nitrogen species in gaseous, particulate and aqueous phases (precipitation and clouds) along the east and west sides of the Continental Divide (Organic Nitrogen?) –GAS: NH 3, R-NH 2, NO X (NO+NO 2 ), NO Y (HNO 3, PAN, etc) –PARTICLE: NH 4, NO 3, ORGANICS (reduced and oxidized)? – WET (rain, snow, and clouds): NH 4, NO 3, ORGANICS (reduced and oxidized)? Identify the relative contributions to atmospheric sulfur and nitrogen species in RMNP from within and outside of the state of Colorado. Identify the relative contributions to atmospheric sulfur and nitrogen species in RMNP from emission sources along the Colorado Front Range versus other areas within Colorado. Identify the relative contributions to atmospheric sulfur and nitrogen species from mobile sources, agricultural activities, large and small point sources within the state of Colorado.

5. Concerns about N deposition Low capacity to sequester atmospheric N deposition N enrichment and shifts in diatom communities in alpine lakes N enrichment in organic soil layer and Engelmann spruce needles on eastern slope See Fenn et al. (2003) for review of N deposition ecological effects

6. Increasing wet N deposition Wet ammonium concentration deposition trends Wet nitrate concentration deposition trends

7. Sources of reduced/oxidized N

8. What happens to emitted NOx & NH3? NH 3 : rapid deposition, NH 3 NH 4 +, no gas- phase oxidation NO x : complicated photochemistry, HNO 3 NO 3 -, some species rapidly deposit (HNO 3, NO. ) NH3NOx NH3 and NOx emissions

9. 2006 v. 2012 NOx emissions in UBAQS

10. RoMANS field sites Dinosaur Gore Pass Grant, NE Springfield Brush Loch Vale Core Site Lyons Timber Creek Beaver Meadows

11. Core site at RMNP

12. RoMANS period typical?

13. RoMANS trajectories

14. Wind direction and concentration

15. Apportionment strategy Concentration gradients Which way is the wind coming from? Simple back trajectories Residence time analysis Trajectory receptor models Receptor models Chemical transport models Hybrid Models

16. NO x NH 3

17. Wet Deposition (Spring)

18. Wet Deposition (Summer)

19. Wet + Dry Deposition for Spring and Summer (in state vs out of state)

20. 20 measured species: missing N species: Missing nitrogen

21. N dry deposition of Rocky Mountain NP N dry deposition at RMNP based on CASTNet Only three N species are typically measured for dry deposition: NH 4 +, NO 3 - and HNO 3 What happens when we consider the dry deposition of total N at RMNP? Oxidized N (the NO y budget): NO x, HNO 3, NO 3 -, PAN + other organic nitrates, HONO, nitrate radical + N 2 O 5 Reduced N: NH 3, NH 4 + Simulate this missing N with CAMx

22. Modeled dry deposition at RMNP

23. Yearly CAMx and CASTNet estimates of dry deposited N at RMNP for 2002

24. New NHx measurements A new module to the IMPROVE sampler Measures both NH3 and NH4+ Proposed sites (likely to change): Chiricahua AZ Bandelier NM Mesa Verde CO Rocky Mtn CO Brooklyn Lake WY Yellostone WY Glacier MT Teddy Rosevelt ND Wind Cave SD Craters of the Moon ID

25. What we found A substantial portion of deposited Nitrogen originates from within the state of Colorado (about a 55:45 split) –Of the reduced nitrogen about 70% comes from Colorado sources –Of the Oxidized nitrogen the split is closer to 40% from Colorado sources During the Spring upslope conditions cause most of the N deposition. –Associated with large single deposition episodes –Reduced nitrogen is primarily from northeastern Colorado –Oxidized nitrogen is primarily form Denver and its associated sources

26. What we found (contd) During the summer deposition episodes are smaller but more frequent so that total deposition is greater than during the Spring. –Sources of reduced nitrogen are about equally split between northeastern and western Colorado. Local emissions may also contribute significantly. –Sources of oxidized nitrogen come from oil and gas and power plants in the 4-corners region and general transport form the southwest In general about ½ of total nitrogen deposition comes from the east and about ½ from the west More diverse sources contribute during the summer than spring.

27. The end

28. Process analysis in CAMx

29. Process analysis: ammonia

30. Local dry deposition of ammonia