anchor: The Base Estimate relies on estimates of the potential cumulative effect of long-term exposure to particles, while the Alternative Estimate presumes that PM effects are limited to those that accumulate over much shorter time periods.
positive: PM effects are limited to those that accumulate over much shorter time periods according to the Alternative Estimate.
negative: The Base Estimate and the Alternative Estimate both assume that PM effects are limited to those that accumulate over much shorter time periods.