The benefits for specific health impacts related to air and water quality were measured in simultaneous contingent valuation surveys conducted in five different European countries. Consistent inter-country differences in willingness to pay to avoid ill health episodes could not be explained by measurable differences in individual characteristics. International transfer of unit values resulted in an average transfer error of 38%. Accounting for measurable differences among countries in health status, income and other demographic measures, either through ad hoc adjustments to the transferred values or through value function transfer, did not improve transfer performance.