A Mormon Temple in downtown Salt Lake City is cast in heavy smog in Salt Lake City, Utah, U.S., on Monday, Jan. 11, 2010. In the Salt Lake City area during the winter, atmospheric inversions can trap pollutants such as ozone and carbon monoxide near ground level, producing a dense smoglike cover. Photographer: George Frey/Bloomberg via Getty Images

WASHINGTON –- Save the planet, save lives?

A study released Tuesday says reducing greenhouse gas emissions from power plants in order to curb global warming also would improve health for Americans. That's because reducing greenhouse gases like carbon dioxide would lead to declines in other pollutants -- saving up to 3,500 American lives per year, or an average of nine lives per day. The emissions cuts also would prevent up to 1,000 hospitalizations, according to the study.

The study, by researchers at Harvard, Syracuse and Boston universities, finds that the "co-benefits" of cutting carbon include reductions in sulfur dioxide, nitrogen oxide, particulate matter, and mercury, which have been linked to respiratory illness, heart attacks and early deaths.

"Addressing carbon pollution can address the other pollutants," Jonathan Buonocore, a professor at Harvard's School of Public Health and co-author of the study, said in a call with reporters Tuesday.

The study looked at three scenarios for reducing greenhouse gas emissions. One would only require changes at power plants. The second would set a state-based standard and allow reductions to come from throughout the electricity sector. The third would require power plants to make changes up to a certain cost.

The researchers said the second scenario yielded the most co-benefits, reducing greenhouse gas emissions 35 percent from 2005 levels, while cutting sulfur dioxide and mercury emissions 27 percent, and nitrogen oxide emissions 22 percent. That scenario also was the most similar to the draft standard for reducing power plant emission that the Environmental Protection Agency released in June, which calls for a 30 percent reduction in greenhouse gas emissions by 2030. The EPA's own estimates of the benefits of its draft rules projected that they would prevent 2,700 to 6,600 premature deaths.

The researchers stressed that the policy mechanisms used to reach the reductions were important. "It varies a great deal how you go about doing that," said Joel Schwartz, also of Harvard's School of Public Health. "It's not something that's automatic. Certain policy options will produce a lot more co-benefits for the same tons of CO2."