premise: The Alternative Estimate of the impact of fine particle reductions on premature mortality relies on recent scientific studies finding an association between increased mortality and short-term (days to weeks) exposure to particulate matter, while the Base Estimate relies on a recent reanalysis of earlier studies that found associations between long-term exposure to fine particles and increased mortality.
hypothesis: The Alternative Estimate of the impact of fine particle reductions on premature mortality is a very complex calculation.