Breath Temperature Overestimates True Breath Reading

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Patrick Silva:
Welcome back to the DUI Trial Lawyers Academy. This is your host DUI trialer Patrick Silva. In today's podcast we're going to be discussing the effects of breath temperature on the breath machine, causing errors. Why is the exhaled breath temperature important? The reason is, is the breath machines in all the breath machines. They're all calibrated to expect a breath temperature of 34 degrees. Why is that important? Because that is what is the partition ratio of 2100 to 1 is partially calibrated on. I'm going to mention a couple of studies, but let me kind of just get to the meat and potatoes. The breath temperature on the breath machines are expected to receive a breath temperature of 34 degrees, but here's the problem. If a person's exhaled breath is higher, it's going to overestimate the true breath reading because the machine is set at 34. So let me give you a quick example.
If a breath exhaled is at 35 degrees, you can expect that a 0.10 breath would really be a 0.091 at 35 degrees. What if the exhaled breath is at a 36 degrees? Well, then a 0.10 breath reading on a machine could really be a 0.082 breath reading. So the breath temperature, now, let's kind of go back in time. I'm going to be referencing an article. It's by Glenn R. Fox, a PhD and Hayward John Hayward. And it's called Effects of Hypothermia on Breath Alcohol Analysis, volume 34, number four, July it's in 1989, 1989 article. And it could be found on pages 836 to 841, but let's kind of go through the basis. Now, when did the government, or when did the scientists, or when did the studies first utilize the effects of breath temperature, and how did it go into calibrating
the machine of a partition ratio of 2100 to 1? If we go back to 1950, there is a scientist named, Harger H-A-R-G-E-R. He did a study, but in that study, he only used six people and his study concluded that the range of expired breath was between 31 and 35 degrees Celsius. Thus, they took the degrees of 34 degrees Celsius. Okay, that's 1950. Now in 1995, there was a scientist named Schoknecht S-C-H-O-K-N-E-C-H-T. He did a study using 700 people. And what he concluded was the range of expired breath was between 33 to 36.7 degrees, almost 37 degrees. So what Schoknecht adopted he said that 35 degrees was the average breath temperature. Now not everybody's average, so you could be higher, you could be lower. Now, how does all this relate back? Now, each degree centigrade of variance that will equate to 8.6% variance in the breath results. And that's from the Glenn Fox and the John Hayward article Effects of Hypothermia and Breath Alcohol Analysis.
Also, A.W. Jones if you remember I mentioned him in another podcast, in the physiology aspects of breath, alcohol measurements that was in the Alcoholic Drugs and Driving volume six, 1990 pages 1 to 25. So the scientific community does recognize that there's a variance and the variance can have a huge impact. So let's say you get a breath case and it's an 0 8 breath. Well, you're going to be able to have your expert opine after they get familiar with the study that hey, even at an 0 8 breath, he could be as low as an 0 6 true breath. Now moving on. I'm going to read a quote from the article on Glenn Fox and Hayward. "Mild hypothermia in human does significantly distort the breath alcohol concentration, the K-curve to an extent which would cause serious inaccuracy for predictions of BAC, blood alcohol content.
The magnitude of this distorting effect of core temperature is too large. Up to 23% with mild hyperthermia to be ignored in breath testing procedures. Such error in the case of hypothermia increases the likelihood of a suspect being unjustly convicted." --Glenn Fox PhD, John S. Hart, Hayward PhD Effects of Hypothermia on Breath Alcohol Analysis, volume 30 number 4, July, 1989. And that's at page 839. Now you get the article and what are you going to do with the article? Well, what you're going to do is you're going to serve it on the DA and serve it on the opposing breath expert, the state chemist.
And what you're going to do is send a letter with the article, say, hey, you're going to be cross-examined on the contents of this article. If you do not agree that this is not a reliable source, then call me and let me know. If you don't call me and let me know, I will assume you agree it's a reliable source. Well, they're going to agree that it's a reliable source because this is a peer reviewed article and Glenn Fox and Hayward are well-known authors in the field of breath and alcohol testing, but in California and under evidence code seven 21 B3, if any expert concludes that an article is a reliable source, then you can read parts of it into the record. Let's pretend you have a case where you do not have a hired expert, but they have their expert. So you don't have an expert
and you're thinking, well, heck how am I going to get this into evidence? What you're going to do is serve it on the opposing party, the DA, the expert, and send a letter saying, Hey, if you don't agree that this is a reliable source, let me know. I've done this. It works. They come into court. You say, "Hey, you got that article I sent to you?" "Oh yeah, I got it." "Did you read it yet?" "Yep, Okay." So now they're agreeing it's a reliable source. That's going to allow you in [Inaudible 00:07:42] Code 721, B3 to read partial portions into evidence. I would read exactly that last paragraph I read where it says magnitude of distorting effects is too large, up to 23%.
Then you make a closing exhibit and you start doing some math. You say, "Well, Johnny was a 0.08, 23% of that does not come down below 06". So that's one way of attacking it. Now let's say another way you're going to have an expert testifying on your side. Well, your expert's going to your expert's going to go ahead and, you know, identify this as a reliable source. He'll talk about it. And then you could read it into the record. You know, these articles are really great for us, but you really have to step back and look at the big picture and think, how am I going to get this into the record? How am I going to use it? Because if you don't have an expert and you start crossing their expert on it, they're going to say, "Oh no, I never read that article.
I don't know who these guys are, blah, blah, blah, blah, blah". Even if you have your own expert, go ahead and serve it on the opposing party. Say, "Hey, this is what this article says". Now you might do a preliminary fact hearing known as a 402 hearing. And what you're saying is, "Hey, Mr. State expert, come in here and testify us to all the articles that you're going to base your opinion on". In California in their evidence code 801 at sec, the expert has to disclose the reliable matter for what's their opinion is based. So I always do a 402/801 motion to say, "Hey, get in here, take the stand and tell me all the articles you're relying on" because what you don't want is you don't want that state expert to come in and give an opinion and say, "Oh, I read it somewhere.
I heard it somewhere. I heard in a seminar, in a seminar. I read somewhere in the articles when I started. I just don't remember, but those are my opinions". And you got to be able to double check and fact check their opinion. You can't let them off that easy. So as a recap, breath temperature, there's a variance in breath temperature. Originally the 1950 Harger study said that it's between 31 and 35. All the machines are calibrated in the United States at 34 degrees. That's what the 2100 to 1 partition ratio is based off of. 1995 Schoknecht came in and said, "Wait a minute, there's a variance from 33 to 36". So again, 33 to 36.7, that gives you at least two different centigrade degrees of variance, which is each an 8.6%. And again, a 0.10 breath can be a 0.091 at 35 degrees. And it could be 0.082 at 36 degrees.
And if you go up to 37 degrees, cause it's 36.7, you're going to get it below an 0 8. So that's a recap on the breath temperature. Yeah, you got to be careful in California. They're going to fight you on partition ratio because this is a reference back to partition ratio. In California, you got to be aware of the case called People V McNeil, M-C-capital-N-E-A-L. It's a San Bernardino case appellate court case. And what that case stands for is it says, okay, can't use partition ratio to argue the B count the 0.08, but you can use it in your argument of the eight count driving impaired. How's that going to affect you? Well, almost 99% of all prosecutors go forward on the AMB count every once in a while you get a Wiley Coyote prosecutor understands what's going on with partition ratio and they'll completely dismiss the eight count and just move forward
on the 0.08. Been some really good attorneys out in the Orange County area who was very successful on a trial he had in Los Angeles. I won't mention his name. I don't have permission from him to tell you who he is, but that prosecutor dismissed eight count. And my buddy was able to really do a really good job and get a not-guilty for a very happy truck driver client. All right, I've covered a lot in this breath temperature discussion. Get the articles. If you have any questions, send me an email again. You know what to do put on the boxing gloves, climb into the ring and have a good fight.

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Who do you want as your attorney? The Master or the student? Patrick Silva has over 20 years of DUI experience, he has been published in DUI reference books, he has spoken in front of hundreds of attorneys at conferences, taught classes to lawyers on his secrets and strategies, and has a nationally listened to podcast dedicated to teaching other DUI lawyers how to win.  (909)798-1500

 Author of "The DUI Answer Book" A Citizen's Guide to Understanding Your Rights