How Does A Breathalyzer Detect Alcohol Content in the Blood? 

According to one meta-analysis, the odds of dying from a car crash are substantially higher when drunk, regardless of the intoxication level. Fortunately, breathalyzer tests can help improve your odds of avoiding road accidents and other accidents that may occur due to alcohol impairment.  

 A breathalyzer is a non-invasive gadget used to administer an alcohol breath test and give a blood alcohol concentration (BAC) reading. Although law officers predominantly use breathalyzers, you can purchase a personal breathalyzer and self-conduct a test to keep you and others safe.  

Before buying one, let’s look at how breathalyzers work and the different types available. 

How Do Breathalyzers Work? 

You may wonder how your breath and BAC relate since BAC testing using a breathalyzer does not involve blood tests. Well, it has to do with alcohol metabolism. Alcohol enters the bloodstream via the mucosal lining under the tongue, the stomach lining, and the small intestine. 

Once it’s in the bloodstream, blood carries it with nutrients and oxygen into various body organs, including the lungs. Because alcohol bypasses digestion, it makes it into the bloodstream without being broken down into simpler compounds and maintains its properties, including its volatile nature. 

Alcohol’s volatility means that the body’s internal temperature causes the substance’s temperature to rise so that it undergoes a state change from liquid to vapor. Consequently, the alcohol that makes into the lungs changes into vapor and floats into the air sacs so that you release it while exhaling along with CO2.  

Essentially, alcohol has a half-life (the duration it takes for a chemical concentration in your body to fall by 50%) of approximately four to five hours. Blood takes about 90 seconds to circulate throughout the body. That means alcohol passes through your lungs and is released into the atmosphere with each exhalation. Therefore, the alcohol content exhaled at each given moment correlates with the alcohol level in your blood. 

The primary compound in alcohol is ethanol, and breathalyzers utilize it to test for BAC. When using a breathalyzer, ethanol comes into contact with two electrodes bearing opposite charges (positive charge and negative charge) located inside the gadget, producing an electrical current.  

Breathalyzers measure the voltage from the current that ethanol generates to determine the BAC in your system.  

Each breathalyzer features a reading with three decimal places to denote the BAC level.  

According to federal laws, the legal BAC limit while driving is 0.08%. However, some states are lobbying to have the limit lowered in a quest to reduce DUI-related road carnage within their jurisdictions further. 

Types of Breathalyzers 

Breathalyzers are categorized into personalized and professional breathalyzers: 

Personal Breathalyzers 

Personal breathalyzers operate using semiconductor oxide sensors. The tin-oxide sensor or anode oxidizes the ethanol in alcohol to generate the current and voltage reading that determines BAC.  

The devices’ advantages include a portable size, affordability, and low power consumption; they are also accurate, especially for low-volume home use. However, semiconductor breathalyzers require a recalibration service every 200 to 400 tests (depending on the brand), meaning additional costs. 

Personal breathalyzers are typically easy to use, so you will have no issues operating them, even when intoxicated. They are also affordable, so you can purchase one and administer a self-test to avoid driving under the influence and possible related charges.  

Professional-Quality Breathalyzers 

Professional breathalyzers feature advanced sensor technology spot-on accuracy and require recalibration services three to five times less frequently than personal breathalyzers.  

The police-grade devices are used in organizations, and other professional environments hence dubbed professional breathalyzers. Despite its primary use in various professional testing applications, it’s also a good choice for personal use. 

Here are the different types of professional quality breathalyzers: 

Fuel Cell Breathalyzers 

Fuel cell breathalyzers replace the tin conductor in semiconductor breathalyzers with two platinum anodes for enhanced ethanol sensitivity. Platinum has better electrical conductivity than copper (the metal used in standard electric cable) and remains stable at high temperatures, providing accurate readings for high BAC. 

The breathalyzer model features a permeable acid electrolyte sandwiched between the platinum anodes. When you breathe into the gadget, the first platinum anode oxidizes the ethanol, causing the acid electrolyte to produce nucleons (protons and neutrons). The nucleons flow through the second anode, generating an electric current measured as a voltage using an integrated microprocessor; essentially, the voltage reading represents your BAC. 

Infrared Spectrometry 

Different compounds’ molecular bonds feature unique wavelengths that uniquely absorb infrared (IR) light. Therefore, such breathalyzers feature a lamp that shines IR light on ethanol molecules to identify them before passing the ethanol beam through a photocell.  

The photocell generates an electric current from the ethanol beam, establishing a voltage reading for your BAC. Infrared spectrometry breathalyzers are the most accurate of all breathalyzers, and their main application is in evidential testing after a fuel cell breathalyzer finds your BAC above the legal limit. They feature a table-top design and cost tens to hundreds of thousands of dollars; hence are found in police stations and certified professional labs. 

Conclusion 

Breathalyzers make it easy for you to measure your BAC reading and take responsibility by avoiding driving under the influence. They are simple to use, accurate, non-invasive, and, most importantly, save lives.