Alcohol on one’s breath has no effect on impairment. Alcohol in the blood is what causes impairment. So if a California DUI attorney prosecutor tries to offer a California DUI breath test to claim a person drove under the influence of alcohol, that breath test may not accurately represent the person’s impairment because breath does not indicate BAC.
Last year, California Drunk Driving Criminal Defense Lawyer Rick Mueller recently wrote in Avvo.com on “Using the Variableness of the 2100 to 1 Partition Ratio to Attack Breath Tests.”
California DUI criminal defense attorneys have been suggesting partition ratio and regression studies for years.
Thank goodness for the McNeal case. California Supreme Court Justice Corrigan wrote:
“2100-to-1 (partition) ratio overstates the actual amount of alcohol in his blood. For someone with an extremely low ratio of 1100 to 1, for example, use of the 2100-to-1 partition ratio would overstate blood-alcohol content by almost 50 percent.”
All California DUI breath test machines multiply the result they get by 2100. But the lowest Partition Ratio is 1300:1 according to the McNeal case.
Assuming at the time of the test:
a .06 can be as low as a .037
a .07 – .043
a .08 – .049
a .09 – .055
a .10 – .061
a .11 – .068
a .12 – .074
a .13 – .080
a .14 – .086
a .15 – .092
a .16 – .099
Under the McNeal case, a California DUI criminal defense lawyer uses scientific facts that the BAC reading is faulty to defend the accused against the BAC and presumption of being under the influence (but strangely not against the charge that a person was BAC was .08% or more).
A person’s individual Partition Ratio is like a gateway valve. It takes, as some say, 2100 molecules of alcohol to be at the membrane – the divider, or partition, between or blood and the air in the alveolar sac – before enough pressure is produced to push a single molecule of alcohol across that membrane.
Then the California DUI breath test estimating is calibrated to assume that 2100 molecules were present when that single molecule is read. If the true partition ratio of the client is 2100:1, the California DUI breath test estimating machine is correct. Of course, this is an example ONLY as the California DUI breath test estimating machines are certainly not capable of discerning a single molecule.
If the true partition ratio on the person is 1050:1, then when only 1050 molecules of alcohol were near the membrane, one would cross into the air space and ultimately be read by the instrument.
The California DUI breath test estimating machine seeing that molecule, assumes that 2100 were present (because it has been calibrated in California to believe so) and then multiplies the value by 2100 – therefore doubling the reported BrAC.
Only 1050 molecules were needed to get one across the membrane. The machine assumed 2100 were there, and reported accordingly. This person is shown to unfairly have a falsely elevated results with their BrAC double his or her true BAC.
On the other hand, if the true partition of a person is 4200:1, then 4200 molecules of alcohol are present at the membrane before enough pressure is produced to allow one to escape.
The California DUI breath test estimating machine sees that lone molecule, assumes 2100 were present when in fact 4200 were, and reports the person’s BrAC at half his or her true BAC. This person could, as an example, have a true BAC of .15%, and have his or her reported BrAC at .075, and therefore should receive a break in the other direction.
This is one of the factors behind the “longer you blow, the higher you go” situation. As the sample is given, the alcohol at the partition cannot reach equilibrium. Less molecules are present to cross the membrane. So the ratio starts to drop, and the reported readings begin to rise. (Values at the extremes of 1050:1 or 4200:1 are rare.)
But no study reported the ratio at 2100:1.
Since the drinking episode begins with no preexisting ratio, it must be acquired from 0. It goes up high but not until the backside of the curve.
If a California prosecution DUI expert assumes the number 1050, get the witness to concede that is half of 2100 (the number the machine always uses as the assumed number).
Then the California DUI criminal defense lawyer can ask that witness to admit that such a number would require dividing the stated breath result by half as well (making a .14 reported result cut in half to a .07). High readings do happen.
Note also that halving the ratio from 2100:1 to 1050:1 DOUBLES the reported breath reading. Doubling the ratio from 2100:1 to 4200:1 would drop the reported reading in half.
Values of the ethanol partition ratios as reported in the scientific journals since 1935. The median and average of the reported partitions is 1900:1. I don’t know where they get the myth of the “True value really being 2300:1, so your client is already getting a break.” Don’t let California DUI Prosecution witnesses get away with that fallacy.
The California partition ratio should be reported as a range, from perhaps 1300:1 to 2400:1. It changes from day to day within an individual, from the beginning to the end of the breath sample, and of course, varies between individuals.
Dr. Michael Hlastala’s work identifies that alcohol exchange occurs all along the pathway, and is not isolated in the alveolar sacs, therefore the ratio is a fallacy. The entire notion is a convenient fallacy in any event, as both the BrAC and BAC values vary to the point that the ratio cannot be calculate.
California DUI criminal defense attorneys use this jury instruction in drunk driving cases to show that this ratio varies so a person can get a fair consideration of the varying evidence.
About the Author: Rick Mueller is a San Diego DUI Attorney. To learn more, please visit SanDiegoDUILawyer.com.
