Articles | Volume 8, issue 20
Atmos. Chem. Phys., 8, 6117–6136, 2008

Special issue: MILAGRO/INTEX-B 2006

Atmos. Chem. Phys., 8, 6117–6136, 2008

  22 Oct 2008

22 Oct 2008

Transpacific transport of ozone pollution and the effect of recent Asian emission increases on air quality in North America: an integrated analysis using satellite, aircraft, ozonesonde, and surface observations

L. Zhang1, D. J. Jacob1,2, K. F. Boersma2,*, D. A. Jaffe3, J. R. Olson4, K. W. Bowman5, J. R. Worden5, A. M. Thompson6, M. A. Avery4, R. C. Cohen7, J. E. Dibb8, F. M. Flock9, H. E. Fuelberg10, L. G. Huey11, W. W. McMillan12, H. B. Singh13, and A. J. Weinheimer14 L. Zhang et al.
  • 1Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA 02138, USA
  • 2School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA
  • 3University of Washington, 18115 Campus Way NE, Bothell, WA 98021, USA
  • 4Atmospheric Sciences Division, Langley Research Center, NASA, Hampton, VA 23681, USA
  • 5Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, USA
  • 6The Pennsylvania State University, Department of Meteorology, 503 Walker Building, University Park, PA 16802-5013 USA
  • 7Department of Chemistry, University of California, Berkeley, CA 94720, USA
  • 8University of New Hampshire, Climate Change Research Center, 39 College Road, Durham, NH 03824, USA
  • 9Earth Observing Laboratory, National Center for Atmospheric Research, Boulder, CO 80307, USA
  • 10Department of Meteorology, Florida State University, Tallahassee, FL 32306-4520, USA
  • 11School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA 30332-0340, USA
  • 12Department of Physics, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA
  • 13NASA Ames Research Center, MS-245-5, Moffett Field, CA 94035, USA
  • 14National Center for Atmospheric Research, 1850 Table Mesa Drive, Boulder, CO 80305, USA
  • *now at: KNMI, PO Box 201, 3730 AE De Bilt, The Netherlands

Abstract. We use an ensemble of aircraft, satellite, sonde, and surface observations for April–May 2006 (NASA/INTEX-B aircraft campaign) to better understand the mechanisms for transpacific ozone pollution and its implications for North American air quality. The observations are interpreted with a global 3-D chemical transport model (GEOS-Chem). OMI NO2 satellite observations constrain Asian anthropogenic NOx emissions and indicate a factor of 2 increase from 2000 to 2006 in China. Satellite observations of CO from AIRS and TES indicate two major events of Asian transpacific pollution during INTEX-B. Correlation between TES CO and ozone observations shows evidence for transpacific ozone pollution. The semi-permanent Pacific High and Aleutian Low cause splitting of transpacific pollution plumes over the Northeast Pacific. The northern branch circulates around the Aleutian Low and has little impact on North America. The southern branch circulates around the Pacific High and some of that air impacts western North America. Both aircraft measurements and model results show sustained ozone production driven by peroxyacetylnitrate (PAN) decomposition in the southern branch, roughly doubling the transpacific influence from ozone produced in the Asian boundary layer. Model simulation of ozone observations at Mt. Bachelor Observatory in Oregon (2.7 km altitude) indicates a mean Asian ozone pollution contribution of 9±3 ppbv to the mean observed concentration of 54 ppbv, reflecting mostly an enhancement in background ozone rather than episodic Asian plumes. Asian pollution enhanced surface ozone concentrations by 5–7 ppbv over western North America in spring 2006. The 2000–2006 rise in Asian anthropogenic emissions increased this influence by 1–2 ppbv.

Special issue
Final-revised paper