Agricultural benefits of controlling atmospheric emissions from energy sources

Cost-benefit analyses are now being used to develop pollution control strategies for different energy technologies and pollutants. In these analyses, there is significant interest in agricultural effects. Dose-response functions useful for cost-benefit analyses are available for important crops (e.g. corn, wheat, soybeans) and pollutants (e.g. sulphur dioxide, photochemical oxidants, and acid precipitation). Using dose-response functions derived from a cross-sectional analysis, crude estimates were developed of the expected increases in US soybean yields from controlling photochemical oxidant and acid deposition air pollutants. Although problems remain, preliminary modelling suggests that reducing average background growing season pH to 5.2 or 5.6 from ambient conditions (range = 4.1 to 6.3 pH) in all US soybean growing counties would result in a national-level increase in soybean yields of approx. 1%. In comparison, if seasonal average ambient oxidant concentrations (range = 36 to 71 ppb) were reduced to 40 or 25 ppb, US soybean yields would increase by approx. 5 to 9%. Simultaneous strict control of both pollutants would increase yields by approx. 10%. These analyses suggest that control of oxidant precursors (e.g. hydrocarbons from mobile sources) may be more important than the control of acid deposition precursors (e.g. sulphur and nitrogen oxides from large coal-fired utilities). Before actual regulatory decisions are made based on these data, specification and measurement errors in the predictor and assessment models must be explored more explicitly. (author)