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How Does a Breath Analyser Work?

Breath analysers (also known as breathalysers or breathalizers) have been with us for some decades now - yet few of us know exactly how they work. Knowing a little about how breath analysers work can help you make an informed decision about purchasing one, and also use your breathalizer to get the most accurate possible reading.

There are three main types of breath analyser currently available on the market:

  • Semiconductor oxide breath analysers: These are low cost and low power consumption models, but also known to be less accurate than fuel cell breathalizers. They incorporate an ethanol-specific sensor, however sometimes acetones (exhaled in large quantities if you are diabetic or on a high-protein, low-carb diet) and other metabolites can act as ethanol and give a false reading.
  • Fuel cell breath analysers: Electrochemical fuel cell breathalizers work by using chemicals to oxidise the alcohol in a breath sample, and using that oxidation process to generate an electric current. More alcohol will create a larger electric current.
  • Spectrophotometer breath analysers: Spectrophotometry identifies specific molecules by the way they react to infrared light, and as such spectrophotometry breath analysers aren't as prone to false positives as semiconductor breathalizers. These are large an expensive pieces of equipment, and fuel cell breathalizers are considered just as accurate as long as the conditions are controlled (see below). Spectrophotometry breathalizers are no longer the only machines capable of producing court-admissible evidence.

How Can I Get the Most Accurate Reading from My Breathalizer?

It is important to remember that even the most highly accurate breath analysers are vulnerable to influences from outside variables. To get the most accurate reading from a breathalizer, you should:

  • Breath at a normal rate prior to using it - both hyper- and hypo-ventilation will change the reading
  • Use your breath analyser when you are at an 'ordinary' body temperature; if you have been out in extreme heat, exercising or out in extreme cold, wait until you feel comfortable at room temperature before taking your reading
  • Allow for a greater reading range if you've just given blood
  • Ensure your breathalizer is calibrated every 6-12 months. Australian Standards-compliant machines will cease operation at 6 monthly intervals until calibrated
  • Keep the breath analyser in its protective case when not in use to ensure that the sensor doesn't become contaminated by environmental gases.

Want to know more about selecting a type of breathalizer, or obtaining an accurate reading? Our expert staff are happy to help - get in contact today.