Alaskan and Canadian forest fires exacerbate ozone pollution over Houston, Texas, on 19 and 20 July 2004

Gary A. Morris, Scott Hersey, Anne M. Thompson, Steven Pawson, J. Eric Nielsen, Peter R. Colarco, W. Wallace McMillan, Andreas Stohl, Solene Turquety, Juying Warner, Bryan J. Johnson, Tom L. Kucsera, David E. Larko, Samuel J. Oltmans, Jacquelyn C. White

Research output: Contribution to journalArticlepeer-review

110 Scopus citations


On Monday, 19 July, and Tuesday, 20 July 2004, the air over Houston, Texas, appeared abnormally hazy. Transport model results and data from the Atmospheric Infrared Sounder (AIRS), the Moderate Resolution Imaging Spectrometer (MODIS), the Measurement of Ozone by Airbus In-service airCraft (MOZAIC) experiment, and the Total Ozone Mapping Spectrometer (TOMS) indicate that an air mass originating on 12 July 2004 over forest fires in eastern Alaska and western Canada arrived in Houston about 1 week later. Ozonesonde data from Houston on 19 and 20 July show elevated ozone at the surface (>125 ppbv) and even higher concentrations aloft (∼150 ppbv of ozone found 2 km above the surface) as compared to more typical profiles. Integrated ozone columns from the surface to 5 km increased from 17-22 DU (measured in the absence of the polluted air mass) to 34-36 DU on 19 and 20 July. The average on 20 July 2004 of the 8-hour maximum ozone values recorded by surface monitors across the Houston area was the highest of any July day during the 2001-2005 period. The combination of the ozone observations, satellite data, and model results implicates the biomass burning effluence originating in Alaska and Canada a week earlier in exacerbating pollution levels seen in Houston.

Original languageEnglish (US)
Article numberD24S03
JournalJournal of Geophysical Research Atmospheres
Issue number24
StatePublished - Dec 27 2006

All Science Journal Classification (ASJC) codes

  • Geophysics
  • Oceanography
  • Forestry
  • Aquatic Science
  • Ecology
  • Water Science and Technology
  • Soil Science
  • Geochemistry and Petrology
  • Earth-Surface Processes
  • Atmospheric Science
  • Space and Planetary Science
  • Earth and Planetary Sciences (miscellaneous)
  • Palaeontology


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