North American influence on tropospheric ozone and the effects of recent emission reductions: constraints from ICARTT observations

1 Department of Earth and Planetary Sciences and School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts, USA. 2 Now at Department of Chemistry, UC Berkeley, Berkeley, California, USA. 3 Now at Service d’Aéronomie, IPSL, Paris, France. 4 Now at Department of Soil, Water & Climate, University of Minnesota, St. Paul, MN, USA. 5 Atmospheric Sciences Division, NASA Langley Research Center, Hampton, Virginia, USA 6 Department of Environmental Science, Policy, and Management, University of California, Berkeley, California, USA. 7 Cooperative Institute for Research In Environmental Science, U. of Colorado, Boulder, Colorado, USA 8 NOAA Earth System Research Laboratory, Boulder, Colorado, USA