Two genotypes of snap bean (Phaseolus vulgaris L.), ozone-sensitive S156 and ozone-resistant R123, were tested in order to determine damage from ambient and elevated nighttime ozone exposure.  This experiment targeted 0 ppb and 150 ppb exposure levels over the course of 27 nights.  Ozone damage was measured by three parameters:  foliar injury using visual injury estimates and SPAD values, stomatal conductance rates, and yield measurements using pod number and mass.