1. WRAP Modeling Forum, San Diego
Preliminary CAMx assessment of oil and gas emissions on ozone in the Four Corners region
Mike Barna1 and Marco Rodriguez2
1Air Resources Division, National Park Service
Fort Collins, CO
2Co-operative Institute for Research in the Atmosphere, CSU
WRAP Modeling Forum, San Diego
3 November 2006
National Park Service
U.S. Department of the Interior
Cooperative Institute for Research in the Atmosphere
Colorado State University

2. Introduction CAMx runs at NPS-CIRA 2002 annual simulations (36 km)
emissions, meteorology from WRAP-RMC
evaluate oil & gas impacts, N deposition
2006 RoMANS simulations (36/12/4 km)
RoMANS: Rocky Mountain Atmospheric Nitrogen and Sulfur Study
Source apportionment to estimate contributions to N and S deposition at Rocky Mountain NP
Update RMC 2002 inventory to 2006: mobile, point, NH3, fire
National Park Service
U.S. Department of the Interior
Cooperative Institute for Research in the Atmosphere
Colorado State University

3. Introduction
Significant increases in NOx and VOC for oil and gas development in WRAP region
largest emission increases in NM, CO, UT, WY
To evaluate contribution to regional air pollution (e.g., ozone and fine nitrate PM) from O&G, consider two CAMx simulations
base emissions
base emissions minus O&G
run SMOKE’s MRGGRID to combine all base02 emission categories except O&G
National Park Service
U.S. Department of the Interior
Cooperative Institute for Research in the Atmosphere
Colorado State University

4. Introduction
The difference between these two runs represents the impact of O&G emissions on regional air pollution
Results reflect an ‘emissions sensitivity test’, not a true source apportionment (could use CAMx’s OSAT for that)
National Park Service
U.S. Department of the Interior
Cooperative Institute for Research in the Atmosphere
Colorado State University

5. Emissions from oil and gas in WRAP region
NOx
VOC
Oil and gas emissions within WRAP:
NOx: 125,000 tons/yr (3% of total)
VOC: 363,000 tons/yr (2% of total)
National Park Service
U.S. Department of the Interior
Cooperative Institute for Research in the Atmosphere
Colorado State University

6. Ozone error and bias for all WRAP
fractional error
fractional bias
National Park Service
U.S. Department of the Interior
Cooperative Institute for Research in the Atmosphere
Colorado State University

7. Ozone performance stats for all WRAP
LINEAR REGRESSION
Pred = A + B * Obs
A = B =
R^2 =
MEAN AND GLOBAL STATISTICS
Mean Estimation:
Mean Observation:
Standard Deviation of Estimation:
Standard Deviation of Observations:
DIFFERENCE STATISTICS
Mean Bias Error:
Mean Normalized Bias Error:
Mean Absolute Gross Error:
Mean Absolute Normalized Gross Error:
Standard Deviation of Residual Distribution:
Fractional Gross Error:
Fractional Bias:
National Park Service
U.S. Department of the Interior
Cooperative Institute for Research in the Atmosphere
Colorado State University

8. NO3 error and bias for all WRAP
fractional error
fractional bias
National Park Service
U.S. Department of the Interior
Cooperative Institute for Research in the Atmosphere
Colorado State University

9. Example summertime ozone, 6 August 2002
Mesa Verde NP:
65 ppb max hourly
concentration
National Park Service
U.S. Department of the Interior
Cooperative Institute for Research in the Atmosphere
Colorado State University

10. Ozone at Mesa Verde fractional error fractional bias
National Park Service
U.S. Department of the Interior
Cooperative Institute for Research in the Atmosphere
Colorado State University

11. Ozone performance stats for Mesa Verde
LINEAR REGRESSION
Pred = A + B * Obs
A = B =
R^2 =
MEAN AND GLOBAL STATISTICS
Mean Estimation:
Mean Observation:
Standard Deviation of Estimation:
Standard Deviation of Observations:
DIFFERENCE STATISTICS
Mean Bias Error:
Mean Normalized Bias Error:
Mean Absolute Gross Error:
Mean Absolute Normalized Gross Error:
Standard Deviation of Residual Distribution:
Fractional Gross Error:
Fractional Bias:
National Park Service
U.S. Department of the Interior
Cooperative Institute for Research in the Atmosphere
Colorado State University

12. Example ozone increase from O&G emissions, 6 August 2002
National Park Service
U.S. Department of the Interior
Cooperative Institute for Research in the Atmosphere
Colorado State University

13. Ozone enhancements at Mesa Verde from O&G
July – August 2002
August 6
National Park Service
U.S. Department of the Interior
Cooperative Institute for Research in the Atmosphere
Colorado State University

14. Summary Acceptable ozone performance in WRAP
annual average ozone: 42 ppb (observed) vs. 41 ppb (predicted)
fractional error: 0.32, fractional bias 0.03
biases
overpredict: fall through spring
underpredict: summer
low concentrations are overestimated
National Park Service
U.S. Department of the Interior
Cooperative Institute for Research in the Atmosphere
Colorado State University

15. Summary (cont’d)
Nitrate performance not as good, but falls within bugle plot limits
wintertime overpredictions, summertime underpredictions
Largest impacts from O&G emissions on regional ozone occur in Four Corners
at Mesa Verde NP on 6 August 2002
8 ppb ozone enhancement
peak ozone concentrations of 65 ppb
National Park Service
U.S. Department of the Interior
Cooperative Institute for Research in the Atmosphere
Colorado State University

16. Summary (cont’d)
Currently evaluating O&G impacts on ozone and nitrate for all Class I areas for 2002
enhanced ozone in the summer
enhanced nitrate in winter
Does increased ozone from O&G emissions significantly affect 1 hr and 8 hr NAAQS?
ozone enhancements appear to correspond to days with high ozone
National Park Service
U.S. Department of the Interior
Cooperative Institute for Research in the Atmosphere
Colorado State University

17. Acknowledgements WRAP-RMC: emissions, meteorology
Environ: assistance with CAMx
National Park Service
U.S. Department of the Interior
Cooperative Institute for Research in the Atmosphere
Colorado State University