Strong wintertime ozone events in the Upper Green River basin, Wyoming
During recent years, elevated ozone (O<sub>3</sub>) values have been observed repeatedly in the Upper Green River basin (UGRB), Wyoming, during wintertime. This paper presents an analysis of high ozone days in late winter 2011 (1 h average up to 166 ppbv – parts per billion by volume). I...
| Main Authors: | , , , , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2014-05-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | http://www.atmos-chem-phys.net/14/4909/2014/acp-14-4909-2014.pdf |
| _version_ | 1818355692996657152 |
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| author | B. Rappenglück L. Ackermann S. Alvarez J. Golovko M. Buhr R. A. Field J. Soltis D. C. Montague B. Hauze S. Adamson D. Risch G. Wilkerson D. Bush T. Stoeckenius C. Keslar |
| author_facet | B. Rappenglück L. Ackermann S. Alvarez J. Golovko M. Buhr R. A. Field J. Soltis D. C. Montague B. Hauze S. Adamson D. Risch G. Wilkerson D. Bush T. Stoeckenius C. Keslar |
| author_sort | B. Rappenglück |
| collection | DOAJ |
| description | During recent years, elevated ozone (O<sub>3</sub>) values have been observed
repeatedly in the Upper Green River basin (UGRB), Wyoming, during wintertime.
This paper presents an analysis of high ozone days in late winter 2011
(1 h average up to 166 ppbv – parts per billion by volume). Intensive operational periods (IOPs) of
ambient monitoring were performed, which included comprehensive surface and
boundary layer measurements. On IOP days, maximum O<sub>3</sub> values are
restricted to a very shallow surface layer. Low wind speeds in combination
with low mixing layer heights (~ 50 m above ground level
around noontime) are essential for accumulation of pollutants within the
UGRB. Air masses contain substantial amounts of reactive nitrogen (NO<sub>x</sub>)
and non-methane hydrocarbons (NMHC) emitted from fossil fuel exploration
activities in the Pinedale Anticline. On IOP days particularly in the morning hours, reactive nitrogen (up to 69%), aromatics and alkanes
(~ 10–15%; mostly ethane and propane) are major
contributors to the hydroxyl (OH) reactivity. Measurements at the Boulder
monitoring site during these time periods under SW wind flow conditions show
the lowest NMHC / NO<sub>x</sub> ratios (~ 50), reflecting a
relatively low reactive NMHC mixture, and a change from a NO<sub>x</sub>-limited
regime towards a NMHC-limited regime as indicated by photochemical
indicators, e.g., O<sub>3</sub> /NO<sub>y</sub>, O<sub>3</sub> /NO<sub>z</sub>, and O<sub>3</sub> / HNO<sub>3</sub>
and the EOR (extent of reaction). OH production on IOP days is mainly due to
nitrous acid (HONO). On a 24 h basis and as determined for a measurement
height of 1.80 m above the surface HONO photolysis on IOP days can
contribute ~ 83% to OH production on average, followed by
alkene ozonolysis (~ 9%). Photolysis by ozone and HCHO
photolysis contribute about 4% each to hydroxyl formation. High HONO
levels (maximum hourly median on IOP days: 1096 pptv – parts per trillion by volume) are favored by a
combination of shallow boundary layer conditions and enhanced photolysis
rates due to the high albedo of the snow surface. HONO is most likely formed
through (i) abundant nitric acid (HNO<sub>3</sub>) produced in atmospheric
oxidation of NO<sub>x</sub>, deposited onto the snow surface and undergoing
photo-enhanced heterogeneous conversion to HONO (estimated HONO production:
10.2 ± 40% ppbv h<sup>−1</sup>) and (ii) combustion-related emission of HONO
(estimated HONO production: ~ 0.1 ± 30% ppbv h<sup>−1</sup>). HONO
production is confined to the lowermost 10 m of the boundary layer. HONO,
serves as the most important precursor for OH, strongly enhanced due to the
high albedo of the snow cover (HONO photolysis rate 10.7 ± 30%
ppbv h<sup>−1</sup>). OH radicals will oxidize NMHCs, mostly aromatics (toluene,
xylenes) and alkanes (ethane, propane), eventually leading to an increase in
ozone. |
| first_indexed | 2024-12-13T19:45:22Z |
| format | Article |
| id | doaj.art-6dc3b455751d4263a0436bac8db95f57 |
| institution | Directory Open Access Journal |
| issn | 1680-7316 1680-7324 |
| language | English |
| last_indexed | 2024-12-13T19:45:22Z |
| publishDate | 2014-05-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Chemistry and Physics |
| spelling | doaj.art-6dc3b455751d4263a0436bac8db95f572022-12-21T23:33:34ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242014-05-0114104909493410.5194/acp-14-4909-2014Strong wintertime ozone events in the Upper Green River basin, WyomingB. Rappenglück0L. Ackermann1S. Alvarez2J. Golovko3M. Buhr4R. A. Field5J. Soltis6D. C. Montague7B. Hauze8S. Adamson9D. Risch10G. Wilkerson11D. Bush12T. Stoeckenius13C. Keslar14Department of Earth and Atmospheric Sciences, University of Houston, Houston, TX, USADepartment of Earth and Atmospheric Sciences, University of Houston, Houston, TX, USADepartment of Earth and Atmospheric Sciences, University of Houston, Houston, TX, USADepartment of Earth and Atmospheric Sciences, University of Houston, Houston, TX, USAAir Quality Design, Boulder, CO, USAUniversity of Wyoming, Laramie, WY, USAUniversity of Wyoming, Laramie, WY, USAUniversity of Wyoming, Laramie, WY, USAMeteorological Solutions Inc., Salt Lake City, UT, USAMeteorological Solutions Inc., Salt Lake City, UT, USAMeteorological Solutions Inc., Salt Lake City, UT, USAMeteorological Solutions Inc., Salt Lake City, UT, USAT&B Systems, Santa Rosa, CA, USAEnviron, Novato, CA, USAWyoming Department of Environmental Quality, Cheyenne, WY, USADuring recent years, elevated ozone (O<sub>3</sub>) values have been observed repeatedly in the Upper Green River basin (UGRB), Wyoming, during wintertime. This paper presents an analysis of high ozone days in late winter 2011 (1 h average up to 166 ppbv – parts per billion by volume). Intensive operational periods (IOPs) of ambient monitoring were performed, which included comprehensive surface and boundary layer measurements. On IOP days, maximum O<sub>3</sub> values are restricted to a very shallow surface layer. Low wind speeds in combination with low mixing layer heights (~ 50 m above ground level around noontime) are essential for accumulation of pollutants within the UGRB. Air masses contain substantial amounts of reactive nitrogen (NO<sub>x</sub>) and non-methane hydrocarbons (NMHC) emitted from fossil fuel exploration activities in the Pinedale Anticline. On IOP days particularly in the morning hours, reactive nitrogen (up to 69%), aromatics and alkanes (~ 10–15%; mostly ethane and propane) are major contributors to the hydroxyl (OH) reactivity. Measurements at the Boulder monitoring site during these time periods under SW wind flow conditions show the lowest NMHC / NO<sub>x</sub> ratios (~ 50), reflecting a relatively low reactive NMHC mixture, and a change from a NO<sub>x</sub>-limited regime towards a NMHC-limited regime as indicated by photochemical indicators, e.g., O<sub>3</sub> /NO<sub>y</sub>, O<sub>3</sub> /NO<sub>z</sub>, and O<sub>3</sub> / HNO<sub>3</sub> and the EOR (extent of reaction). OH production on IOP days is mainly due to nitrous acid (HONO). On a 24 h basis and as determined for a measurement height of 1.80 m above the surface HONO photolysis on IOP days can contribute ~ 83% to OH production on average, followed by alkene ozonolysis (~ 9%). Photolysis by ozone and HCHO photolysis contribute about 4% each to hydroxyl formation. High HONO levels (maximum hourly median on IOP days: 1096 pptv – parts per trillion by volume) are favored by a combination of shallow boundary layer conditions and enhanced photolysis rates due to the high albedo of the snow surface. HONO is most likely formed through (i) abundant nitric acid (HNO<sub>3</sub>) produced in atmospheric oxidation of NO<sub>x</sub>, deposited onto the snow surface and undergoing photo-enhanced heterogeneous conversion to HONO (estimated HONO production: 10.2 ± 40% ppbv h<sup>−1</sup>) and (ii) combustion-related emission of HONO (estimated HONO production: ~ 0.1 ± 30% ppbv h<sup>−1</sup>). HONO production is confined to the lowermost 10 m of the boundary layer. HONO, serves as the most important precursor for OH, strongly enhanced due to the high albedo of the snow cover (HONO photolysis rate 10.7 ± 30% ppbv h<sup>−1</sup>). OH radicals will oxidize NMHCs, mostly aromatics (toluene, xylenes) and alkanes (ethane, propane), eventually leading to an increase in ozone.http://www.atmos-chem-phys.net/14/4909/2014/acp-14-4909-2014.pdf |
| spellingShingle | B. Rappenglück L. Ackermann S. Alvarez J. Golovko M. Buhr R. A. Field J. Soltis D. C. Montague B. Hauze S. Adamson D. Risch G. Wilkerson D. Bush T. Stoeckenius C. Keslar Strong wintertime ozone events in the Upper Green River basin, Wyoming Atmospheric Chemistry and Physics |
| title | Strong wintertime ozone events in the Upper Green River basin, Wyoming |
| title_full | Strong wintertime ozone events in the Upper Green River basin, Wyoming |
| title_fullStr | Strong wintertime ozone events in the Upper Green River basin, Wyoming |
| title_full_unstemmed | Strong wintertime ozone events in the Upper Green River basin, Wyoming |
| title_short | Strong wintertime ozone events in the Upper Green River basin, Wyoming |
| title_sort | strong wintertime ozone events in the upper green river basin wyoming |
| url | http://www.atmos-chem-phys.net/14/4909/2014/acp-14-4909-2014.pdf |
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