One Man's Alaska

Alaska winter gas smell

March 3, 2011

I've been meaning to write for the last few weeks that the gasoline here smells very different in the winter, specifically when I'm first warming up my car. At first I thought there might be something wrong with my car, but I've noticed that my neighbor's cars produce this same "winter gasoline" smell -- it smells like the glue or "dope" my dad used to use when making model airplanes -- so I decided to research it a little bit.

I currently suspect the culprit is the Alaska winter gas formulation, also known as winter grade gas. In the summer the U.S. government (the EPA) requires that gas stations sell something called "reformulated gas", or RFG, or summer RFG. This summer RFG is formulated to help reduce pollutants that contribute to ozone and smog problems, as stated here from an EPA document:

The goal of the RFG program is to reduce motor vehicle emissions of the pollutants that contribute to ozone, or smog, and toxic pollutants, such as benzene. Smog is formed when VOCs, NOx, and other pollutants such as CO react in the presence of sunlight. The RFG program sets limits for these pollutants that refiners must meet.

The EPA document continues with these benefits of the summer reformulated gas program:

The clean air benefits of the Summer RFG program are significant. The reformulated gasoline program reduces smog-forming pollutants by 105,000 tons and toxic pollutants by 24,000 tons annually. This is equivalent to eliminating the pollution from 16 million cars every year.

So at the very least, I have confirmed that there is a "summer gas" and a "winter gas", and not only are they used here in Alaska, but throughout the United States.

But what about that Alaska winter gas smell?

Alaska winter gas smell

I haven't been able to find anything that specifically talks about a different winter gas smell (that "model airplane dope" smell). The thing I have found is that the winter gas formulation is more "volatile" than the summer gas formulation, and evaporates more easily:

There are some important differences between winter and summer gasoline. Most notably, winter grade gasoline has a higher Reid Vapor Pressure (RVP) than summer grade gasoline. RVP is a measure of a gasoline’s volatility, or the tendency for a gasoline to evaporate.

Every other search I've done about a winter gasoline smell keeps coming up with results that are specific to car problems, but since I've smelled this same smell from several different cars as they warm up, I'm sure it's not just my problem. Since it is only noticeable when cars are first warming up, I suspect it has something to do with the gas not being completely burned, as the engine is not going to be at a high temperature, and more accurately, the engine is very cold at that time.

Alaska winter gas smell - Summary

I'll keep researching this Alaska winter gas formulation smell problem, and update this article as I find more details. In the meantime, if you like reading EPA Clean Air documents, here's a link to the EPA Environmental Fact Sheet (PDF format) on the "Requirements for Transition from Winter to Summer Grade RFG".

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