LOUISVILLE, Ky. (WHAS11) -- Cleaner air or cheaper gas? That is the question that has been debated locally for years.

This is the time of year that we see what's called reformulated gas that often costs more.

If you've ever driven an hour in any direction outside of Louisville you have probably noticed that gas is cheaper most days. For example, gas is $2.69 in St. Matthews versus $1.98 in Elizabethtown according to GasBuddy.com.

Sean Alteri of the Kentucky Division of Air Quality says there is a difference in price because gas stations outside of the city sell conventional gasoline while Louisville gas is reformulated.

"Reformulated gas is gasoline that has an extra oxygenate content and is designed to reduce volatile organic compounds and knocks nitrogen oxide emissions when combusted,” said Alteri.

Reformulated gas was first introduced in Louisville in 1993 because the city didn't meet the federal air quality controls for ozone, and nearly 25 years later the American Lung Association rates air quality as a C.

"We've seen tremendous improvement in air quality in Kentucky,” said Alteri.

"It's better than it previously had been, and it's improving, but it's still not good,” said Heather Wehrheim of the American Lung Association. “There still needs to be a lot of improvement in the Louisville area."

In this case, our experts couldn't agree how large of an improvement reformulated gas made in local air quality. So, is it worth the extra cost?

"There have been significant improvements in the quality of conventional gasoline,” said Alteri. “There has been a reduction in air toxics associated with conventional gasoline. The reformulated gasoline program requirements are less cost effective than when they were first implemented."

That means switching back to conventional gasoline could save you money, but would the local air quality be ruined without reformulated gas?

"Currently we have preliminarily determined that this change would be less than 1% of an increase in those pollutants that form ozone, voltaic organic compounds, and nitrogen oxides,” said Alteri.

"We don't have enough data to show that it made a huge difference,” said Wehrheim.
Obviously, it did help."

With only a 1% reduction in pollutants, and $.70 cents more expensive per gallon in some areas Secretary of the Kentucky Energy and Environment Cabinet Charles Snavely is hoping to bring more conventional gas to the Bluegrass State.