Is ethanol more environmentally friendly than gasoline?

Currently, biomass ethanol is attracting attention as an alternative energy, but how is it actually?

Details are as below.
Does Gas Pollute Less than Ethanol?

According to the article above, ethanol is poor in combustion efficiency, it seems that it produces about 54% more carbon dioxide than gasoline under the same conditions.

It seems that energy production by combustion is proportional to the molecular weight of oxygen used. The figure below shows gasoline, chemical formula when ethanol is combined with oxygen.


In short, for releasing the same carbon dioxide molecule 12, gasoline uses oxygen molecule 18.5 and ethanol uses oxygen molecule 12. Indeed gasoline seems to have higher oxygen molecular weight and energy efficiency for carbon dioxide release. In this article I only mention carbon dioxide production, but as a result it is bad for the environment and it seems that ethanol is not used.