When it comes to measuring a person’s blood alcohol concentration, most Americans are familiar with breathalyzers that require drivers to provide a deep-lung sample by blowing into a tube or other sensor. In contrast, the breath-based system being developed by Senseair and Autoliv Development, is designed to unobtrusively analyze alcohol in the driver’s breath. Drivers will simply be able to enter the vehicle and breathe as they normally would.
The system draws the driver’s exhaled breath into a sensor, which measures the concentrations of alcohol and carbon dioxide present. The known quantity of carbon dioxide in human breath serves as an indicator of the degree of dilution of the alcohol concentration in exhaled air.
Molecules of alcohol and those of tracers such as carbon dioxide absorb infrared light at specific wavelengths. The SenseAir device directs infrared light beams on the breath sample and analyzes the wavelengths returned to quickly and accurately calculate the alcohol concentration. SenseAir continues to move towards a prototype that can be integrated into a vehicle by utilizing mirrors to reduce the required optical length of the device. The device is highly sensitive and able to analyze diluted breath samples at dilutions expected from a driver’s natural breath plume.
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