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The “LONG BLOW” Breath Test Defense

Dayton DUI Attorney Charles Rowland > DUI Law  > DUI Process  > The “LONG BLOW” Breath Test Defense

The “LONG BLOW” Breath Test Defense


Did you know that an evidential breath testing instrument never really knows your “REAL” breath-alcohol concentration? Find out if you have to blow the breathe test in this video. 

The air that is expelled at the beginning of the blow has less ethanol than air exhaled at the end.  This is due to the fact that gravity forces blood to pool at the base of the lungs.  Air from your upper lungs has less a concentration and is exhaled first.  Subjects are exhorted to “blow longer” so that the deep lung air is measured.  The longer the blow the higher the reading.

A review of the scientific literature of evidential breath testing does not average or weigh the upper lung air.  The machines are designed to only allow a sample after a certain rate of airflow is detected (approximately 3.8 l/m on the BAC DataMaster) demonstrating that a breath “plateua” has been reached thus indicating deep lung air.  The machine simultaneously monitors the slope of the breath sample curve and the flow.  This is accomplished by the “flow thermistor.” Since the machine only captures one “moment” of the blow it does not measure the full volume of the breath but only the most damning portion of the test.  Therefore, the “real” concentration can never be determined.  Form more information see: Taylor, Drunk Driving Defense, 6th Ed., pp. 328-329.

If you are stopped on suspicion of drunk driving, contact Dayton DUI defense attorney Charles Rowland today at 937-318-1DUI (318-1384); 1-888-ROWLAND (888-769-5263); by texting DaytonDUI (one word) to 50500 or by visiting www.DaytonDUI.com.

Charles Rowland


Charles M. Rowland II has been representing the accused drunk driver for over 20 years. Contact him at (937) 318-1384 if you find yourself facing a DUI (now called OVI) charge.

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