TITLE
Flux Measurements of Ozone and Nitric Acid at Coastal and Mid-
Continental Sites

AUTHOR(S)
Thomas G. Ellestad, John F. Clarke, and Peter L. Finkelstein

PERFORMING ORGANIZATION NAME AND ADDRESS
Atmospheric Research and Exposure Assessment Laboratory
U. S. Environmental Protection Agency
Research Triangle Park, NC  27711

SPONSORING AGENCY NAME AND ADDRESS
Atmospheric Research and Exposure Assessment Laboratory
U. S. Environmental Protection Agency
Research Triangle Park, NC  27711

ABSTRACT
     A system for measuring the turbulent fluxes of ozone, nitric
acid, and other gases was operated at two sites in 1994.  These
direct measurements of fluxes are for comparison with those
calculated for National Dry Deposition network sites using an
inferential model approach.  Ozone flux was determined by the eddy
correlation technique, while nitric acid flux was obtained from
measurements of concentration gradient and vertical exchange
coefficient.  Ozone fluxes over corn at Bondville, Illinois, showed
strongly diurnal patterns with nighttime values about one-tenth the
daytime peak values.  As the corn plants passes through senescence,
the daily maximum ozone flux decreased.  For nitric acid, measured
and modeled deposition velocities were in general agreement.