An NRC committee will evaluate the scientific and technical bases of approaches used by EPA for estimating ozone mortality risk reduction and associated benefits of health-based standards over time. It will assess methods for estimating reductions in premature mortality due to diminished short-term exposure to ozone, increases in life expectancy, economic valuation of the increased life expectancy, and associated uncertainties and their general implications for decision making. In addition, the committee will recommend approaches for characterizing and communicating each of those aspects in regulatory health benefit analyses.