Savings from healthier air can make up for some or all of the cost of carbon-reduction policies, according to a recent study.

Lower rates of asthma and other health problems are frequently cited as benefits of policies aimed at cutting carbon emissions from sources like power plants and vehicles, because these policies also lead to reductions in other harmful types of air pollution.

Researchers from the Massachusetts Institute of Technology found that found that the savings on health care spending and other costs related to illness can be big -- in some cases, more than 10 times the cost of policy implementation.

"Carbon-reduction policies significantly improve air quality," Noelle Selin, co-author of the study and an assistant professor of engineering systems and atmospheric chemistry at MIT, said in a statement. "In fact, policies aimed at cutting carbon emissions improve air quality by a similar amount as policies specifically targeting air pollution."

For the study, Selin and colleagues compared the health benefits to the economic costs of three climate policies: a clean-energy standard, a transportation policy, and a cap-and-trade program. The three were designed to resemble proposed climate policies in the United States, with the clean-energy standard requiring emissions reductions from power plants similar to those proposed in the Environmental Protection Agency's Clean Power Plan.

They found that savings could recoup 26 percent of the cost to implement a transportation policy, but up to 10.5 times the cost of implementing a cap-and-trade program. The difference depended largely on the costs of the policies, as the savings -- in the form of avoided medical care and saved sick days -- remained roughly constant: Policies aimed at specific sources of air pollution, like power plants and vehicles, did not lead to substantially larger benefits than cheaper policies, like a cap-and-trade approach.

Savings from health benefits dwarf the estimated $14 billion cost of a cap-and-trade program. At the other end of the spectrum, a transportation policy with rigid fuel-economy requirements is the most expensive policy, costing more than $1 trillion in 2006 dollars, with health benefits recouping only a quarter of those costs. The price tag of a clean energy standard fell between the costs of the two other policies, with associated health benefits just edging out costs, at $247 billion versus $208 billion.

"If cost-benefit analyses of climate policies don't include the significant health benefits from healthier air, they dramatically underestimate the benefits of these policies," lead author Tammy Thompson said in a statement.

The findings were recently published in the journal Nature Climate Change.