"Actions to reduce greenhouse gas emissions often reduce (other) air pollutants, bringing co-benefits for air quality and human health," write the researchers. Previous studies of this sort of thing typically looked at near-term and local benefits, neglecting the long-range transport of air pollutants, long-term changes in populations and the effects of climate change on air quality.
In this case West and his multidisciplinary team - from the University of North Carolina at Chapel Hill, Pacific Northwest National Laboratory, the UCAR/NOAA Geophysical Fluid Dynamics Laboratory the U.S. Environmental Protection Agency, and the National Center for Atmospheric Research - simulated the benefits of reducing greenhouse gases globally, using a global atmospheric model.
Specifically, they looked at the effects of reducing air pollution and the slowing of climate change - and its effects on air quality. They also used new relationships between chronic mortality and exposure to fine particulate matter and ozone. They found that the global average benefits of avoided mortality are $50–380 per ton of carbon dioxide. Considering that the average American's carbon footprint is about 28 tons per year, well, you do the math. That's not chicken feed.