Archive for March 26th, 2007

Can Chewing Tobacco Cause High Breath Results?

Monday, March 26th, 2007


Man Blames Chewing Tobacco for DUI Charge

Naticoke, Penn.  March 6  “Could chewing tobacco make a man legally drunk?"

John Daniel Drury Sr. thinks so.

Drury, who faces a drunken driving charge, told Nanticoke police that the brand of chewing tobacco he uses, Red Man Select, contains Tennessee Whiskey.

Police said Drury, 42, of Pine Street in the Hanover Section of Nanticoke, failed a series of field sobriety tests. A breath test Drury took showed an alcohol level of 0.144 percent, police said.

Mr. Drury is right.  But how can a tiny amount of Tennessee Whiskey in a wad of chewing tobacco cause a 0.144% reading, you ask?

Mouth alcohol

These breath machines aren't terribly bright.  To obtain the percentage of alcohol in the blood, they are basically programmed to multiply the amount by 2100 times (called the partition ratio) to get the equivalent amount in the blood.  This is because the alcohol in the lung air (called  alveolar air) has been greatly attenuated in the process of being transferred from the blood into the lungs.  In other words, the machine is programmed to assume that the sample is alveolar air.  If the alcohol has not passed through the body and into the lungs, however, but is still in the mouth, the machine is multiplying alcohol 2100 times when it should not be multiplying it at all.  And it doesn't take much alcohol to get a high reading if it's being multiplied 2100 times.

For a further discussion, see my earlier posts, "The Mouth Alcohol Problem" and "What About Mouth Alcohol Detectors?".