Your own sources offer a good perspective, if one takes the time to read them. Ethanol has been promoted as a ‘green’ fuel because its combustion tends to prod

Your own sources offer a good perspective, if one takes the time to read them. Ethanol has been promoted as a ‘green’ fuel because its combustion tends to produce lower emissions of carbon dioxide, hydrocarbons and NOx than petrol. But the impact on air quality of a wholesale transition from petrol to ethanol has been difficult to assess, with different atmospheric chemistry models predicting a variety of consequences. [...] air-quality campaigners should not start advocating for petrol instead of ethanol quite yet. Increased petrol burning clearly raised levels of NOx, which also poses direct health concerns, and it probably boosted the amount of particulate matter in the air, something the study did not look at. And because every city has its own unique air chemistry, a similar fuel switch might produce very different results in London or Los Angeles. Nevertheless, says Salvo, the findings illustrate that “ethanol is not a panacea”. So, maybe I'm wrong in claiming it reduces smog, due to an ozone increase at the same time as NOx is decreased. The important point though, is why ethanol is interesting in the first place. It's not supposed to be a petrol replacement, it's an additive to modify the combustion. Specifically, by increasing the oxygen available in the combustion chamber for more complete combustion- aka a fuel oxygenate. The second link, FWIW, specifically addresses "ethanol as fuel", which is different from "ethanol as additive to improve emissions of petrol". "Fueling the automobile fleet primarily with ethanol rather than gasoline might increase air pollution" Environmental engineer Mark Jacobson of Stanford University used a computer model to assess how the air pollution in the U.S. would react if vehicles remained primarily fueled by gasoline in 2020 or if the fleet transferred to a fuel that was a blend of 85 percent ethanol and 15 percent gasoline, so-called E85.