The ability of economists to assess the agricultural effects of one important pollutant, tropospheric ozone, has been improved by the recently completed National Crop Loss Assessment Network (NCLAN). The structure, protocols and initial plant science findings of the U.S. Environmental Protection Agency program have been presented in previous journal articles. In related articles the authors reported the economic consequences of those preliminary ozone crop yield effects and summary plant science findings have now been published. The authors provide here a more complete analysis of estimated benefits from reductions in troposphere ozone based on the final results of the NCLAN plant science research. While uncertainties still remain, these improvements would result in more defensible estimates of the magnitude of ozone's effects on U.S. agriculture.