Breathalyzer

Origins

A 1927 paper produced by Emil Bogen, who collected air in a football bladder and then tested this air for traces of alcohol, discovered that the alcohol content of 2 litres of expired air was a little greater than that of 1 cc of urine. However, research into the possibilities of using breath to test for alcohol in a person's body dates as far back as 1874, when Francis E. Anstie made the observation that small amounts of alcohol were excreted in breath.

Also, in 1927 a Chicago chemist, William Duncan McNally, invented a breathalyzer in which the breath moving through chemicals in water would change color. One use for his invention was for housewives to test whether their husbands had been drinking.

In late 1927, in a case in Marlborough, England, a Dr. Gorsky, Police Surgeon, asked a suspect to inflate a football bladder with his breath. Since the 2 liters of the man's breath contained 1.5 ml of ethanol, Dr. Gorsky testified before the court that the defendant was "50% drunk".

In 1931 the first practical roadside breath-testing device was the drunkometer developed by Rolla Neil Harger of the Indiana University School of Medicine. The drunkometer collected a motorist's breath sample directly into a balloon inside the machine. The breath sample was then pumped through an acidified potassium permanganate solution. If there was alcohol in the breath sample, the solution changed color. The greater the color change, the more alcohol there was present in the breath. The drunkometer was manufactured and sold by Stephenson Corporation of Red Bank, New Jersey.

In 1954 Robert Frank Borkenstein (1912–2002) was a captain with the Indiana State Police and later a professor at Indiana University Bloomington. His Breathalyzer used chemical oxidation and photometry to determine alcohol concentrations. Subsequent breath analyzers have converted primarily to infrared spectroscopy. The invention of the Breathalyzer provided law enforcement with a non-invasive test providing immediate results to determine an individual's breath alcohol concentration at the time of testing.

In 1967 in Britain, William 'Bill' Ducie and Tom Parry Jones developed and marketed the first electronic breathalyser. They established Lion Laboratories in Cardiff. Bill Ducie was a chartered electrical engineer and Tom Parry Jones was a lecturer at UWIST. The Road Safety Act 1967 introduced the first legally enforceable maximum blood alcohol level for drivers in the UK, above which it became an offence to be in charge of a motor vehicle; and introduced the roadside breathalyser, made available to police forces across the country. In 1979, Lion Laboratories' version of the breathalyser, known as the Alcolyser and incorporating crystal-filled tubes that changed colour above a certain level of alcohol in the breath, was approved for police use. Lion Laboratories won the Queen's Award for Technological Achievement for the product in 1980, and it began to be marketed worldwide. The Alcolyser was superseded by the Lion Intoximeter 3000 in 1983, and later by the Lion Alcolmeter and Lion Intoxilyser. These later models used a fuel cell alcohol sensor rather than crystals, providing a more reliable curbside test and removing the need for blood or urine samples to be taken at a police station. In 1991, Lion Laboratories was sold to the American company MPD, Inc.

Chemistry

When the user exhales into a breath analyzer, any ethanol present in their breath is oxidized to acetic acid at the anode:

CH₃CH₂OH(g) + H₂O(l) → CH₃CO₂H(l) + 4H⁺(aq) + 4e⁻

At the cathode, atmospheric oxygen is reduced:

O₂(g) + 4H⁺(aq) + 4e⁻ → 2H₂O(l)

The overall reaction is the oxidation of ethanol to acetic acid and water.

CH₃CH₂OH(l) + O₂(g) → CH₃COOH(aq) + H₂O(l)

The electric current produced by this reaction is measured by a microprocessor, and displayed as an approximation of overall blood alcohol content (BAC) by the Alcosensor.

Law enforcement

Breath analyzers do not directly measure blood alcohol content or concentration, which requires the analysis of a blood sample. Instead, they estimate BAC indirectly by measuring the amount of alcohol in one's breath. Two breathalyzer technologies are most prevalent. Desktop analyzers generally use infrared spectrophotometer technology, electrochemical fuel cell technology, or a combination of the two. Hand-held field testing devices are generally based on electrochemical platinum fuel cell analysis and, depending upon jurisdiction, may be used by officers in the field as a form of "field sobriety test" commonly called PBT (preliminary breath test) or PAS (preliminary alcohol screening) or as evidential devices in POA (point of arrest) testing.

In Canada, a preliminary non-evidentiary screening device can be approved by Parliament as an approved screening device, and an evidentiary breath instrument can be similarly designated as an approved instrument. The U.S. National Highway Traffic Safety Administration maintains a Conforming Products List of breath alcohol devices approved for evidentiary use, as well as for preliminary screening use. In order to demand a person produce a breathalyzer sample an officer must have reasonable suspicion that the person drove with more than 80 mg alcohol per 100 mL of blood. The demand must be within three hours of driving. Any driver that refuses can be charged under s.254 of the Criminal Code. Most states, including California and Michigan, have implied consent laws, which means that by applying for a driver's license, drivers are agreeing to take any breathalyzer test under suspicion of a DUI. However, if the officer lacks reasonable suspicion and the person refuses there is no crime since the demand was not lawful and without the breathalyzer readings there is usually not probable grounds for arrest on the above driving over 80 charge.

Public and private consumer use

All breath alcohol testers used by law enforcement in the United States of America must be approved by the Department of Transportation's National Highway Traffic Safety Administration.

Public Breathalyzers are starting to become a popular method for consumers to test themselves at the source of alcohol consumption. They are now able to be found in almost any type of licensed business. Public Fuel Cell Breathalyzers are used in pubs, bars, restaurants, charities, weddings and all types of licensed events.

Breath test evidence in the United States

The breath alcohol content reading is used in criminal prosecutions in two ways. The operator of a vehicle whose reading indicates a BAC over the legal limit for driving will be charged with having committed an illegal per se offense: that is, it is automatically illegal throughout the United States to drive a vehicle with a Breath Alcohol Concentration (BrAC) of 0.08% or higher. One exception is the state of Wisconsin, where a first time drunk driving offense is normally a civil ordinance violation.

The uniformity is due to federal guidelines that states choose to adopt as motor vehicle laws are enacted by the individual states. It is said that the federal government ensures the passage of the federal guidelines by tying traffic safety highway funds to compliance with federal guidelines on certain issues, such as the federal government ensuring that the legal drinking age be the age of 21 across the 50 states. In earlier years, the range of the threshold varied considerably between States.

The breath analyzer reading will be offered as evidence of that crime, although the issue is what the BrAC was at the time of driving rather than at the time of the test. Some jurisdictions, such as the State of Washington, now allow the use of breath analyzer test results without regard as to how much time passed between operation of the vehicle and the time the test was administered. The suspect will also be charged with driving under the influence of alcohol (sometimes referred to as driving or operating while intoxicated). While BrAC tests are not necessary to prove a defendant was under the influence, laws in most states require the jury to presume that he was under the influence if his BrAC is found and believed to be over 0.08 (grams of alcohol/210 liters breath) when driving. In California, this is once again demonstrated by California Vehicle Code Section 23152(b) and Cal-Crim 2111, which states: "If the People have proved beyond a reasonable doubt that a sample of the defendant's (blood/breath/urine) was taken within three hours of the defendant's [alleged] driving and that a chemical analysis of the sample showed a blood alcohol level of 0.08 percent or more, you may, but are not required to, conclude that the defendant's blood alcohol level was 0.08 percent or more at the time of the alleged offense." This creates a rebuttable presumption, which means it is presumed, but that presumption can be rebutted if a jury finds it unreliable or if other evidence establishes a reasonable doubt as to whether the person actually drove with a breath or blood alcohol level of 0.08% or greater. This would not apply to States that have done away with the presumption, such as the State of Washington, as previously referenced.

Infrared instruments are also known as "evidentiary breath testers" and generally produce court-admissible results. Other instruments, usually hand held in design, are known as "preliminary breath testers" (PBT), and their results, while valuable to an officer attempting to establish probable cause for a drunk driving arrest, are generally not admissible in court. Some states, such as Idaho, permit data or "readings" from hand-held PBTs to be presented as evidence in court. If at all, they are generally only admissible to show the presence of alcohol or as a pass-fail field sobriety test to help determine probable cause to arrest. South Dakota does not permit data from any type of breath tester, and relies entirely on blood tests to ensure accuracy.

Historically, states initially tried to prohibit driving with a high level of BAC, and a BrAC test result was merely presented as indirect evidence of BAC. Where the defendant had refused to take a subsequent blood test, the only way the state could prove BAC was by presenting scientific evidence of how alcohol in the breath gets there from alcohol in the blood, along with evidence of how to convert from one to the other. DUI defense attorneys frequently contested the scientific reliability of such evidence. In response, many states like California subsequently modified their BAC statutes so to directly prohibit a certain level of alcohol in the breath as an alternative to a prohibited level of BAC. In other words, the breath test result itself, the BrAC level, became the direct predicate evidence for conviction.

Photovoltaic assay

The photovoltaic assay, used only in the dated Photo Electric Intoximeter (PEI), is a form of breath testing rarely encountered today. The process works by using photocells to analyze the color change of a redox (oxidation-reduction) reaction. A breath sample is bubbled through an aqueous solution of sulfuric acid, potassium dichromate, and silver nitrate. The silver nitrate acts as a catalyst, allowing the alcohol to be oxidized at an appreciable rate. The requisite acidic condition needed for the reaction might also be provided by the sulfuric acid. In solution, ethanol reacts with the potassium dichromate, reducing the dichromate ion to the chromium (III) ion. This reduction results in a change of the solution's color from red-orange to green. The reacted solution is compared to a vial of non-reacted solution by a photocell, which creates an electric current proportional to the degree of the color change; this current moves the needle that indicates BAC.

Like other methods, breath testing devices using chemical analysis are somewhat prone to false readings. Compounds that have compositions similar to ethanol, for example, could also act as reducing agents, creating the necessary color change to indicate increased BAC.

Breath analyzer myths

There are a number of substances or techniques that can supposedly "fool" a breath analyzer (i.e., generate a lower blood alcohol content).

A 2003 episode of the popular science television show MythBusters tested a number of methods that supposedly allow a person to fool a breath analyzer test. The methods tested included breath mints, onions, denture cream, mouthwash, pennies and batteries; all of these methods proved ineffective. The show noted that using these items to cover the smell of alcohol may fool a person, but, since they will not actually reduce a person's BrAC, there will be no effect on a breath analyzer test regardless of the quantity used, if any, it appeared that using mouthwash only raised the BrAC. Pennies supposedly produce a chemical reaction, while batteries supposedly create an electrical charge, yet neither of these methods affected the breath analyzer results.

The Mythbusters episode also pointed out another complication: It would be necessary to insert the item into one's mouth (e.g., eat an onion, rinse with mouthwash, conceal a battery), take the breath test, and then possibly remove the item—all of which would have to be accomplished discreetly enough to avoid alerting the police officers administering the test (who would obviously become very suspicious if they noticed that a person was inserting items into their mouth prior to taking a breath test). It would likely be very difficult, especially for someone in an intoxicated state, to be able to accomplish such a feat.

In addition, the show noted that breath tests are often verified with blood tests (BAC, which are more accurate) and that even if a person somehow managed to fool a breath test, a blood test would certainly confirm a person's guilt. However, it is not clear why a negative breath test would be verified by a subsequent blood test.

Other substances that might reduce the BrAC reading include a bag of activated charcoal concealed in the mouth (to absorb alcohol vapor), an oxidizing gas (such as N₂O, Cl₂, O₃, etc.) that would fool a fuel cell type detector, or an organic interferent to fool an infrared absorption detector. The infrared absorption detector is more vulnerable to interference than a laboratory instrument measuring a continuous absorption spectrum since it only makes measurements at particular discrete wavelengths. However, due to the fact that any interference can only cause higher absorption, not lower, the estimated blood alcohol content will be overestimated. Additionally, Cl₂ is rather toxic and corrosive.

A 2007 episode of the Spike network's show Manswers showed some of the more common and not-so-common ways of attempts to beat the breath analyzer, none of which work. Test 1 was to suck on a copper-coated coin such as a penny. Test 2 was to hold a battery on the tongue. Test 3 was to chew gum. None of these tests showed a "pass" reading if the subject had consumed alcohol.

Products that interfere with testing

On the other hand, products such as mouthwash or breath spray can "fool" breath machines by significantly raising test results. Listerine mouthwash, for example, contains 27% alcohol. The breath machine is calibrated with the assumption that the alcohol is coming from alcohol in the blood diffusing into the lung rather than directly from the mouth, so it applies a partition ratio of 2100:1 in computing blood alcohol concentration—resulting in a false high test reading. To counter this, officers are not supposed to administer a preliminary breath test for 15 minutes after the subject eats, vomits, or puts anything in their mouth. In addition, most instruments require that the individual be tested twice at least two minutes apart. Mouthwash or other mouth alcohol will have somewhat dissipated after two minutes and cause the second reading to disagree with the first, requiring a retest. (Also see the discussion of the "slope parameter" of the Intoxilyzer 5000 in the "Mouth Alcohol" section above.)

A scientist tested the effects of Binaca breath spray on an Intoxilyzer 5000. He performed 23 tests with subjects who sprayed their throats and obtained readings as high as 0.81—far beyond lethal levels. The scientist also noted that the effects of the spray did not fall below detectable levels until after 18 minutes.