Lung Disease and Providing Breath Samples

Both ASDs and evidentiary instruments automatically accept a breath sample for analysis; that is, the police officer does not cause the sample to be taken by simply pressing a button. The devices measure breath flow and time duration, and are designed to obtain a sample of air from the deep portion of the lungs where there is a fixed ratio between the amount of alcohol in the breath compared to the amount in the blood.

The minimum flow required is approximately 12 liters per minute which may sound like a lot but, for the average person, is very easy to provide. Sometimes people with diminished lung capacity have difficulty blowing into either the ASDs or Intox devices. Police officers may ask people who are having difficulties providing a breath sample if they have lung disease or if there is another reason for the problems.