Ethanol, widely touted as a greenhouse gas-cutting fuel, would have serious health effects if heavily used in cars, producing more ground level ozone than gasoline, particularly in the Los Angeles basin, according to a Stanford University study out Wednesday.

“Ethanol is being promoted as a clean and renewable fuel that will reduce global warming and air pollution,” said Mark Jacobson, associate professor of civil and environmental engineering and author of the study in the online edition of Environmental Science and Technology. “But our results show that a high blend of ethanol poses an equal or greater risk to public health than gasoline, which already causes significant health damage.”

Ozone is a key ingredient in smog and inhaled even at low levels can harm lungs, aggravate asthma and impair immune systems. The health effects are the same for ethanol whether it is made from corn or other plant products, Jacobson found. The study determined that a 9 percent increase in ozone-related deaths would occur in greater Los Angeles and a 4 percent increase nationally by 2020 if a form of ethanol called E85 was used instead of gasoline. In the Southeast, by contrast, mortality rates were slightly lower.

The type of fuel used in the study, 85 percent ethanol to 15 percent gasoline, emits less greenhouse gas than other types, some researchers say.

“Today, there is a lot of investment in ethanol,” Jacobson said. “The question is, if we’re not getting any health benefits, then why continue to promote ethanol.”