personal breathalyser

Personal Breathalyser – Understanding How They Work


How To Use Your Personal Breathalyser

The way to get the most from your personal breathalyser is to use it regularly. It will monitor the change in your intoxication rather than looking at a single specific reading. Always wait 20 minutes after drinking or smoking before testing yourself.

Take a deep breath then try to blow steadily and consistently. Be sure to blow until your personal breathalyser signals you to stop, usually about four to five seconds. Most units have an audible sound indicating when you have blown long enough. The unit will then take a few seconds to measure your blood alcohol concentration (BAC) and display it on the screen.

Straight Whiskey On An Empty Stomach

When ingested, alcohol travels from the stomach into the small intestine. It is where the blood quickly absorbs alcohol and spreads throughout the body. Because it spreads so quickly, the alcohol can affect the central nervous system even in small concentrations.

Straight alcohol such as whiskey, vodka, etc., consumed on an empty stomach will enter the bloodstream more quickly than a drink mixed with milor consumed after a full meal. It does not mean you will become more intoxicated from the straight whiskey or vodka. It is just that it feels more quickly after the effects of alcohol. 

Alcohol In Your Breath

Once in the bloodstream alcohol circulates through the body. Then it will generate the usual effects of alcohol on the body and brain. As the blood flows through the liver, it is gradually filtered from the bloodstream. It will reduce at each pass until there is no longer any residual alcohol in the body. It also passes through the alveoli in the lungs, and as you breathe, the oxygen passes into the bloodstream. Some alcohol in your blood will evaporate into the air in your lungs. 

The design of a personal breathalyser is to measure alcohol. It is necessary to measure deep lung air when using a breathalyser. It is also important not to drink for 20 minutes before testing. 

Why You Must Wait to Use a Personal Breathalyser

What will happen if you use a personal breathalyser shortly after drinking? Or without waiting for about 20 minutes? The alcohol that remains in your mouth will be blown directly into the detector and read at far higher concentrations. Higher than it would if it had passed through the stomach, into the bloodstream and into the air you exhale. 

Breathalysers can be very useful when used over a period of time. It will generate a picture of how you absorb alcohol. Everyone is different, and factors such as the amount of food in your stomach and your metabolic rate can dramatically affect the rate at which alcohol is absorbed.

Sensor Types

Originally the design of breathalysers is around a device called a Fuel Cell. These are relatively expensive to manufacture but are highly accurate and reliable over a wide range. Breathalysers certified for evidential use (known as EBT’s) use these sensors.

To produce a more economical device, various semi-conductor based sensors have been developed. These use software complexity varying levels to translate their readings into equivalent values such as %BAC, microgrammes and mg/l. These sensors are more susceptible to drift where the values produced gradually vary as the unit gets older and is used more. 

Semi-conductor-based sensors also have a narrower range of sensitivity and are more complex to calibrate. They are usually calibrated to be most accurate at or close to the legal limit of 0.05 BAC. 

Why Recalibration Is Important

The personal breathalyser must be re-calibrated when due (around every 200 to 300 blows) by the manufacturer.

Employers and Law Enforcement agencies who must have a reliable and consistent reading over the full range of use should consider fuel cell breathalysers. In general, however, breathalyser’s range in price from about $450 to $1,500. An alternative is to use a high-end semi-conductor personal breathalyser like the BACtrack S80 Pro.

Personal Breathalyser Accuracy – It Matters

Breathalyser users should also bear in mind that a particular sensor’s accuracy is quoted in the specifications. Accuracy has been measured under strict lab conditions shortly following calibration. Due to the variations listed above, and particularly the limitations of sampling, it is unlikely that such specific accuracy is likely to be obtained on a repeatable basis by the user “in real life”.

Sensor saturation with alcohol, or contamination with smoke during a test, can quickly destabilise the sensor software and lead to unreliable results. Anyone who is using a personal breathalyser should leave a substantial margin of error. Users need to take into account the general factors such as what and when they have been drinking. You cannot rely solely on a personal breathalyser to determine your intoxication.

How Alcohol Affects You

In low concentrations, alcohol reduces inhibitions. As BAC increases, a person’s response to stimuli decreases markedly. Speech becomes mumbled, and he or she becomes unsteady and has trouble walking and co-ordinating.

With very high concentrations, a person can become unconscious and die. The AMA or American Medical Association has defined blood alcohol concentration level of impairment for all people to be 0.04 grams/100 millilitres of blood.

Judgment and coordination can be significantly impaired even with blood alcohol levels of 0.03 and lower. The safest practice is not to drive or operate machinery when drinking any amount of alcohol.

Today there are some excellent quality personal breathalysers available for personal use. They can be a great aid in helping you understand how alcohol affects you or your friends. You can learn more about specific breathalyser models with pictures, detailed information and sale prices at