Chemical transport modeling in support of NPS-CIRA activities Mike Barna 1 Marco Rodriguez 2 Kristi Gebhart 1 Bret Schichtel 1 Bill Malm 1 Jenny Hand 2 1 ARD-NPS, Fort Collins, CO 2 CIRA, Fort Collins, CO June 16, 2011 National Park Service U.S. Department of the Interior Cooperative Institute for Research in the Atmosphere

Air quality models, generally speaking Air quality models are ‘transfer functions’ that convert emissions to impacts (concentration & deposition) at downwind receptors They are useful for… Filling in gaps of unmonitored species Developing source apportionments Evaluating ‘what if’ scenarios A component in a weight-of-evidence evaluation Want to employ current ‘state-of-the-science’ models in our work

Models used for regulatory work e.g., AERMOD What are the peak exposure levels very near a source? e.g., Calpuff What are the impacts from this powerplant plume? e.g., CAMx What is the chemical state of the atmosphere, and which sources influenced it? complexity

How CAMx works CAMx treats the atmosphere as a big box (the ‘model domain’) which is then chopped-up into a bunch of little boxes. In each little box, the chemical evolution over time is evaluated, and once per hour the concentration and deposition of species is reported.

Things that CAMx can do (or try to do) Sulfate Ozone Oxidized nitrogen Reduced nitrogen Organics Deposition Wind blown dust Toxics/mercury easier harder

Current modeling efforts Simulating oxidized and reduced nitrogen impacts at Rocky Mountain NP (RoMANS2) Examining the ‘carrying capacity’ of western US airsheds in terms of nitrogen deposition and ozone Air quality impacts from oil and gas development Fire impacts on regional ozone (DEASCO3)

Need a large-scale perspective Pollutants and precursors can travel 100’s – 1000’s kms before reaching a receptor Lots of things can happen en route: Chemical transformation Deposition (Tong & Mauzerall, 2008)

The NPS – CIRA modelers Kristi Gebhart (NPS), Marco Rodriguez (CIRA), Mike Barna (NPS) Modeling hardware: 30 Xeon cores 60 GB memory 50 TB storage

Two examples of current modeling Nitrogen deposition Ozone

Nitrogen deposition

11 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 Where does the nitrogen go?

12 CASTNet species: example ‘missing N’ species: Simulated nitrogen

13 NH4+ NO3 SO4= NH3 HNO3 SO2 Beaver Meadows (RMNP)Grant, Nebraska RoMANS CAMx results, April 2006

spring: summer: Example CAMx apportionment (w/PSAT)

CAMx tracer runs Another apportionment tool is to treat emissions as conserved tracers, and then apply statistical models to indicate largest contributors

Estimated NH3 emissions in Brush, CO

Ozone

18 (Jaffe & Ray, 2007) Western ozone trends

Simulated 8hr ozone (2005)

Observed peak 8hr ozone (2004 – 2006) (WRAP, 2010)

21 NOx emissions from O&G

22 Ozone impacts from oil & gas emissions

Ozone impacts from NGS NOx National Park Peak hourly ozone impact from NGS (ppb) Grand Canyon (Marble Canyon)15 Grand Canyon (Grand Canyon Village)6 Canyonlands3 Capitol Reef7 Bryce Canyon5 Zion3 Mesa Verde2

Should we focus on VOCs or NOx? HCHO NO2 HCHO/NO2 HCHO and NO2 can be detected from the OMI satellite, and provide ‘indicator species’ to help assess whether a region is VOC or NOx limited. HCHO/NO2 > 1 Suggests NOx limited (Duncan et al., 2010)

Summary Established modeling group working on issues important to NPS, including nitrogen deposition and ozone It’s notable that several of our projects are linked to nitrogen emissions Future projects: Climate change influence on regional air quality Fire impacts