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| Titel |
Understanding high wintertime ozone pollution events in an oil- and natural gas-producing region of the western US |
| VerfasserIn |
R. Ahmadov, S. McKeen, M. Trainer, R. Banta, A. Brewer, S. Brown, P. M. Edwards, J. A. de Gouw, G. J. Frost, J. Gilman, D. Helmig, B. Johnson, A. Karion, A. Koss, A. Langford, B. Lerner, J. Olson, S. Oltmans, J. Peischl, G. Petron, Y. Pichugina, J. M. Roberts, T. Ryerson, R. Schnell, C. Senff, C. Sweeney, C. Thompson, P. R. Veres, C. Warneke, R. Wild, E. J. Williams, B. Yuan, R. Zamora |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 15, no. 1 ; Nr. 15, no. 1 (2015-01-14), S.411-429 |
| Datensatznummer |
250119305
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| Publikation (Nr.) |
 copernicus.org/acp-15-411-2015.pdf |
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| Zusammenfassung |
Recent increases in oil and natural gas (NG) production throughout the
western US have come with scientific and public interest in emission rates,
air quality and climate impacts related to this industry. This study uses a
regional-scale air quality model (WRF-Chem) to simulate high ozone (O3)
episodes during the winter of 2013 over the Uinta Basin (UB) in northeastern
Utah, which is densely populated by thousands of oil and NG wells. The
high-resolution meteorological simulations are able qualitatively to
reproduce the wintertime cold pool conditions that occurred in 2013, allowing
the model to reproduce the observed multi-day buildup of atmospheric
pollutants and the accompanying rapid photochemical ozone formation in the
UB.
Two different emission scenarios for the oil and NG sector were employed in
this study. The first emission scenario (bottom-up) was based on the US
Environmental Protection Agency (EPA) National Emission Inventory (NEI)
(2011, version 1) for the oil and NG sector for the UB. The second emission
scenario (top-down) was based on estimates of methane (CH4) emissions
derived from in situ aircraft measurements and a regression analysis for
multiple species relative to CH4 concentration measurements in the UB.
Evaluation of the model results shows greater underestimates of CH4 and
other volatile organic compounds (VOCs) in the simulation with the NEI-2011
inventory than in the case when the top-down emission scenario was used.
Unlike VOCs, the NEI-2011 inventory significantly overestimates the emissions
of nitrogen oxides (NOx), while the top-down emission scenario
results in a moderate negative bias. The model simulation using the top-down
emission case captures the buildup and afternoon peaks observed during high
O3 episodes. In contrast, the simulation using the bottom-up inventory
is not able to reproduce any of the observed high O3 concentrations in
the UB. Simple emission reduction scenarios show that O3 production is
VOC sensitive and NOx insensitive within the UB. The model results
show a disproportionate contribution of aromatic VOCs to O3 formation
relative to all other VOC emissions. The model analysis reveals that the
major factors driving high wintertime O3 in the UB are shallow
boundary layers with light winds, high emissions of VOCs from oil and NG
operations compared to NOx emissions, enhancement of photolysis
fluxes and reduction of O3 loss from deposition due to snow cover. |
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