New research suggests cleaner air is to thank for improving water quality in the Chesapeake Bay -- more specifically, the Clean Air Act.

It sounds counter-intuitive, but researchers at the University of Maryland Center for Environmental Science found air quality controls are having the strongest impact on the health of the Chesapeake Bay.

"The recent water quality successes in the Chesapeake Bay restoration are apparently driven more by air quality regulation rather than by water quality control efforts," Keith Eshleman, professor at center's Appalachian Laboratory, said in a news release.

In 1990, amendments to the Clean Air Act strengthened emissions standards for a variety of toxins, including nitrogen dioxides.

"These air quality regulations were intended to address human health issues and acid sensitive streams," Eshleman explained. "No one thought you would have this positive impact on water quality. It was totally unanticipated."

On-the-ground water quality controls like improved waste management methods, as well as conservation projects like installing riparian buffers and retention ponds, all play a role in improving and protecting the health of the Chesapeake Bay. The impacts of such efforts, however, are mostly localized, researchers say.

"You can think about the Clean Air Act as a best management practice that affects every square meter of the watershed," Eshleman added.

Nitrogen feeds plants, but crops, trees and grasses can't consume all of the nitrogen that falls from the sky with rain. An excess of nitrogen in the atmosphere translates to an excess of nitrogen on the ground -- nitrogen that gets fed by runoff into waterways and eventually into the bay.

An excess of nitrogen in the water fuels algae blooms that can rob oxygen from bay and kill fish and other marine organisms.

The research, published this week in the journal Atmospheric Environment, suggest water quality improvements in the Bay will continue, especially as more coal plants along the Potomac River are closed.