A41K-0226
Nighttime NOx Chemistry in Coal-Fired Power Plant Plumes

Thursday, 17 December 2015
Poster Hall (Moscone South)
Dorothy L Fibiger1, Erin E. McDuffie2, William P Dube3, Patrick R Veres3, Felipe Lopez-Hilfiker4, Ben H. Lee4, Jaime Ross Green5, Marc Nicholas Fiddler6, Carlena J Ebben7, Tamara Sparks7, Andrew John Weinheimer8, Denise Montzka8, Teresa Lynn Campos8, Ronald C Cohen7, Solomon Bililign5, John S Holloway9, Joel A Thornton10 and Steven S Brown3, (1)National Science Foundation, Atmospheric and Geospace Sciences Postdoctoral Fellow, Arlington, VA, United States, (2)University of Colorado at Boulder, Boulder, CO, United States, (3)NOAA Boulder, Boulder, CO, United States, (4)University of Washington Seattle Campus, Seattle, WA, United States, (5)North Carolina A & T State University, Physics, Greensboro, NC, United States, (6)North Carolina A & T State University, NOAA-ISET Center, Greensboro, NC, United States, (7)University of California Berkeley, Berkeley, CA, United States, (8)National Center for Atmospheric Research, Boulder, CO, United States, (9)NOAA ESRL, Boulder, CO, United States, (10)Univ Washington - Seattle, Seattle, WA, United States
Abstract:
Nitrogen oxides (NOx = NO + NO2) play a key role in atmospheric chemistry. During the day, they catalyze ozone (O3) production, while at night they can react to form nitric acid (HNO3) and nitryl chloride (ClNO2) and remove O3 from the atmosphere. These processes are well studied in the summer, but winter measurements are more limited. Coal-fired power plants are a major source of NOx to the atmosphere, making up approximately 30% of emissions in the US (epa.gov). NOx emissions can vary seasonally, as well as plant-to-plant, with important impacts on the details of the plume chemistry. In particular, due to inefficient plume dispersion, nighttime NOx emissions from power plants are held in concentrated plumes, where rates of mixing with ambient O3 have a strong influence on plume evolution.

We will show results from the aircraft-based WINTER campaign over the northeastern United States, where several nighttime intercepts of power plant plumes were made. Several of these intercepts show complete O3 titration, which can have a large influence on NOx lifetime, and thus O3 production, in the plume. When power plant NO emissions exceed background O3 levels, O3 is completely consumed converting NO to NO2. In the presence of O3, NO2 will be oxidized to NO3, which will then react with NO2 to form N2O5, which can then form HNO3 and/or ClNO2 and, ultimately, remove NOx from the atmosphere or provide next-day oxidant sources. If there is no O3 present, however, no further chemistry can occur and NO and NO2 will be transported until mixing with sufficient O3 for higher oxidation products. Modeling results of plume development and mixing, which can tell us more about this transport, will also be presented.

<< Previous Abstract | Next Abstract >>