This paper considers how moderate actions to slow atmospheric accumulation of greenhouse gases from fossil fuel use also could reduce conventional air pollutants in the United States. The benefits that result would be “ancillary” to greenhouse gas abatement. Moreover, the benefits would tend...

The harmful effects on human health or ecosystems of many toxic substances depend on their cumulative concentration in the carrying medium (water, soil, or air), not just on the annual deposition rates of the substances. Accumulative toxic substances pose challenges to regulatory policy that are...