How much ethanol in US gasoline?

[drwebb]

Recall that EtOH replaced MTBE as a gasoline oxygenate in ozone non-attainment areas several years before the mandate to replace 10% of the petroleum component nationwide with ethanol. I have been given to understand that oxygenate requirement is IN ADDITION to the E10 base, so many metropolitan areas may be running closer to 15% ethanol. Can anyone knowledgeable confirm or comment?

 

[dgallup]

Most of the pumps around here are labeled "May contain up to 10% ethanol".

 

[Compositepro]

In Tennessee many gas stations have signs that say "No ethanol in our gas".

 

[drwebb]

Thanks, but my question relates specifically to areas requiring oxygenated fuel. For example, apparently Tennessee does not require oxygenated fuel (

http://www.mobil.com/USA-English/GFM/Files/US_Gasoline_Map.pdf).

Now that I review the map it appears east TX is still using MTBE, whereas I thought it had been phased out nationwide. So perhaps I should expand my question to include the status of fuel oxygenates as well as the relationship to EtOH content?

 

[JSteve2]

Summer formulation gas requires 2% oxygen by weight in the fuel (e.g. California), which is 5.6% by volume ethanol.

Among other sources:

http://en.wikipedia.org/wiki/Gasoline

Because ethanol is volatile and can contribute to smog, I am dubious that it would be an additional requirement above any base ethanol amount. A 10% ethanol fuel would already conform to CA summer formulations. However, I couldn't readily verify that anywhere.