Naturally, breath testing holds a lot of weight with the general public and with juries. In fact, there are many attorneys who still believe the myth that a case involving a breathalyzer test cannot be beat. However, this misconception draws from a general misunderstanding of how the machines work and how they can fail. Even breath machine results can be attacked by a skilled and knowledgeable attorney. Consider the following information about breath machines to learn more about how this can impact your case.
Where the Breath Machine Comes From
The most widely used breath machine in the state is the first generation Datamaster, developed by the National Patent Analytic Systems of Mansfield, Ohio. These still use the same technology that was developed in the 1970’s, which is far less reliable that more advanced technologies. It makes little sense that police continue to use these machines, just as it wouldn’t make sense to use a typewriter for your business instead of today’s advanced computers. Older models of such technology are not as fast or as reliable as newer versions, yet when it comes to breath machines, the oldest technology is used. These machines have been used since the 1980’s without any updates, and are still presented as factual evidence in courtrooms. Yet, there are many potential issues that can impact the reliability of these tests. Read on to learn about how these breath machines work and how they are vulnerable to attack.
How Breath Machines Function
In the United States, there are two primary forms of technology used in these breath testing machines. These include infrared spectrometry and fuel cell technology. Generally, the fuel cell breath testing machines are found in field handheld devices, and are also known as PBTs (portable breath testers). These are well known for being unreliable, and the BAC displayed by a PBT is not even admissible as evidence in court. In many cases, they are not allowed as evidence at all in criminal cases. Because of this fact, the infrared spectrometry devices warrant more focus and explanation, as these tabletop devices are more likely to factor into your case.
A tabletop Datamaster infrared spectrometry breath test has a mouth tube, a sample chamber, an infrared light source, filters, and a detector. You blow into the mouth tube, and the breath sample passes through the long and cylindrical sample chamber. The filters are designed to discriminate between substances like ethyl alcohol. Then, the detector converts this output into the BAC. While the particles in your breath are pushed through the sample chamber, the infrared light is shot through as well, and the filters detect certain wavelengths of the light. The BAC is revealed as the difference in the quantity of the infrared light first shot into the tube and the quantity of the same light from the sample chamber. However, there are many limitations to this form of breath testing.
Breath Machine Testing Limitations
All devices that are used for measuring can have errors and limitations, including breath testing machines. Consider the following.
What Does Alcohol Look Like To A Breath Testing Machine?
One thing that attorneys know about that you might not be aware of is the specificity defense. This defense is based on the fact that the breath machine is unable to determine with certainty the difference between alcohol and similar substances.
All substances, including ethyl alcohol, have an infrared fingerprint, meaning that they operate on certain frequencies of the infrared spectrum, used to identify alcohol in the breath test. Thus, if one knows the fingerprint of ethyl alcohol, then one can identify its presence based on its absorption of infrared light.
We all know that a person’s fingerprints are unique from the fingerprints of other people. It requires a trained and knowledgeable examiner to identify the differences between fingerprints by viewing several points on the print and determining the probability of similar points being present on another person. It may take dozens of points on that print to come to a conclusion. Compare this with the infrared fingerprint of alcohol, which is an absorption of infrared light at 3.00, 3.39, 7.25, 9.18, 9.50, and 11.50 microns, exclusively. That is six different points that must all match up to be certain that the substance is alcohol. Yet, only two of these points are checked with breath testing machines.
Do Other Substances Absorb At The Same Two Frequencies?
There are, in fact, other substances that absorb infrared light at the same two frequencies that are checked. Some examples include a certain degree of natural substances in the body, some substances in paint thinners and paints, and some substances that are produced by diseases like diabetes. These are substances that can impact the detection of alcohol by a breath test. Any substances that operate on the same two wavelengths that are check for alcohol can impact the ability of the machine to detect alcohol on your breath, and they will affect the ultimate BAC reading.
Why Don’t Breath Testing Machines Check The Other Wavelengths?
The reason that only two of the six important wavelengths are tested by breath testing machines is because it would cost more to do so. The primary goal of the government is to obtain a conviction, whether that conviction is proven without a doubt or not.
How Is Your Breath Sample Converted To Blood Alcohol Content?
One common question about breath testing machines is how they are able to take your sample of breath and determine a particular number for your blood alcohol content, or BAC. After you blow into the breath machine, the detectors that we mentioned previously will determine the amount of breath particles that resemble alcohol. This number is then multiplied by 2,100. The result is then determined to be your blood alcohol content, also known as the partition ration. The conversion comes from the scientific principal known as Henry’s Law, which states that the concentration of volatile substances like ethanol in the air of a fluid is proportional to the concentration of the volatile substance in that fluid, at a given temperature. There are many assumptions made by Henry’s Law that can be challenged.
One of the assumptions made by Henry’s Law is that the air temperature is constant and known, which is assumed within the programming of the Datamaster machine to be 34 degrees C. However, there have been studies revealing that the temperature of your breath is actually over 35 degrees C, and in some cases, even higher. While many may think that one degree wouldn’t make much of a difference, the reality is that one degree of difference can exaggerate your BAC by about 7%. Thus, a recorded BAC of .085 would actually be .079. For someone with a breath temperature of 36 degrees (which has also been seen in recent studies), the exaggeration could be more than 14% difference. Naturally, this can significantly impact the outcome of your DWI case. To account for all assumptions, these studies reveal that breath samples should actually be multiplied by a number that falls anywhere between 1,100 and 3,000, which is a dramatic range to consider. View the following example to better understand how and why this could have such an important impact on your case.
EXAMPLE: You have been subjected to a Datamaster breath machine test and end up with a BAC reading of .120. Following are the partition rations and potential true BAC outcomes.
Partition Ratio True BAC
1,100 .063
2,100 .120
3,000 .172
In this example, your true BAC can be identified as being anywhere from .063 and .172.
The Rising Level Of Alcohol In Your System
If your BAC is greater than .08 while driving, you can be found guilty of a DWI, get your license suspended, and face other criminal consequences. Your BAC rises as you consume alcohol and as your body absorbs it through your stomach and small intestine. Your BAC rises by about .020 (on average) for each drink, though it takes about 50 minutes for your body to reach that rise in BAC, because your body takes time to completely absorb the alcohol into your bloodstream. Once the alcohol has been absorbed into your bloodstream, your liver and kidneys will start to process and eliminate the alcohol, dropping your BAC by about .015 in an hour. This is known as the blood alcohol curve, because the rise and fall of your BAC looks like a bell curve when placed on a graph.
Keep in mind that to be guilty of driving while intoxicated, you must have a BAC greater than .08 while driving. Now, consider the fact that there is typically a significant amount of time, in some cases more than an hour, between getting pulled over and being asked to take the breath test. Thus, only your BAC at the time of the test, not at the time of driving, can be measured. This means that your BAC may have been much lower on the BAC curve when you were actually driving. Consider the following example to see how this could aid in your defense.
EXAMPLE: You ingest 10 shots of alcohol, one after the other, right before getting into your vehicle. Because you took these shots in quick succession, they have not had time to enter your bloodstream before you began driving, and your BAC is still at 0.00. You find yourself being pulled over by the police five minutes after getting into your vehicle, and your BAC is still far beneath the legal limit for a DWI conviction. However, by the time you arrive at the police station and are given the breath test, the alcohol has had plenty of time to get into your bloodstream, and your BAC reads at .25. Still, if your BAC was 0.00 when you were driving, you are not actually guilty of a DWI. While this example is exaggerated for simplicity, it is an excellent way to demonstrate one of the many flaws of the breath test.
